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Revision 366 - (hide annotations) (download)
Mon Jul 14 15:45:32 2008 UTC (5 years, 9 months ago) by ph10
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Lazy qualifiers were not always working in UTF-8 mode (8.0/15).

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 366
66     15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
67     /^[^d]*?$/8 failed to match "abc".
68 ph10 351
69 ph10 357
70 ph10 347 Version 7.7 07-May-08
71 ph10 321 ---------------------
72    
73     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
74 ph10 345 a string to a long long, pretend we don't even have a long long." This is
75 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
76 ph10 345
77 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
78     pre-7.6 versions, which defined a global no_arg variable instead of putting
79 ph10 332 it in the RE class. (See also #8 below.)
80 ph10 345
81     3. Remove a line of dead code, identified by coverity and reported by Nuno
82     Lopes.
83    
84 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
85 ph10 321
86 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
87 ph10 345 of files, instead of just to the final components.
88    
89 ph10 324 (2) If there was more than one level of directory, the subdirectories were
90     skipped unless they satisfied the include/exclude conditions. This is
91     inconsistent with GNU grep (and could even be seen as contrary to the
92     pcregrep specification - which I improved to make it absolutely clear).
93     The action now is always to scan all levels of directory, and just
94     apply the include/exclude patterns to regular files.
95 ph10 345
96 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
97 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
98    
99 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
100 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
101 ph10 326 doesn't support NULs in patterns.
102 ph10 345
103     7. Added some missing "const"s to declarations of static tables in
104     pcre_compile.c and pcre_dfa_exec.c.
105    
106 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
107 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
108 ph10 345 first patch. And a third patch - this was a messy problem.)
109 ph10 321
110 ph10 345 9. Applied Craig's patch to remove the use of push_back().
111    
112 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
113     matching function regexec().
114 ph10 345
115     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
116     which, however, unlike Perl's \g{...}, are subroutine calls, not back
117 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
118     Oniguruma does).
119 ph10 345
120     12. Previously, a group with a zero repeat such as (...){0} was completely
121 ph10 335 omitted from the compiled regex. However, this means that if the group
122     was called as a subroutine from elsewhere in the pattern, things went wrong
123 ph10 345 (an internal error was given). Such groups are now left in the compiled
124     pattern, with a new opcode that causes them to be skipped at execution
125 ph10 335 time.
126 ph10 345
127 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
128     to the way PCRE behaves:
129 ph10 345
130 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
131 ph10 345
132     (b) A back reference to an unmatched subpattern matches an empty string
133 ph10 336 (Perl fails the current match path).
134 ph10 345
135 ph10 341 (c) A data ] in a character class must be notated as \] because if the
136 ph10 345 first data character in a class is ], it defines an empty class. (In
137 ph10 341 Perl it is not possible to have an empty class.) The empty class []
138     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
139     The negative empty class [^] matches any one character, independently
140     of the DOTALL setting.
141 ph10 345
142     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
143 ph10 340 non-existent subpattern following a character class starting with ']' and
144     containing () gave an internal compiling error instead of "reference to
145     non-existent subpattern". Fortunately, when the pattern did exist, the
146 ph10 345 compiled code was correct. (When scanning forwards to check for the
147 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
148 ph10 345 the class, so got the count wrong. When actually compiling, the reference
149 ph10 340 was subsequently set up correctly.)
150 ph10 345
151 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
152 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
153     other assertions are supported. I have made pcre_dfa_exec() support
154     (*FAIL).
155    
156 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
157 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
158     cannot be changed at match time, I realized I could make a small
159     improvement to matching performance by compiling OP_ALLANY instead of
160     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
161     on the OP_ANY path.
162    
163     17. Compiling pcretest on Windows with readline support failed without the
164 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
165 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
166    
167 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
168 ph10 345 ncurses library to be included for pcretest when ReadLine support is
169     requested, but also to allow for it to be overridden. This patch came from
170     Daniel Bergström.
171 ph10 347
172 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
173 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
174     any errors with the current Unicode tables. Thanks to Peter Kankowski for
175     spotting this.
176 ph10 324
177 ph10 332
178 ph10 319 Version 7.6 28-Jan-08
179 ph10 300 ---------------------
180    
181 ph10 302 1. A character class containing a very large number of characters with
182     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
183     overflow.
184 ph10 309
185     2. Patch to cut out the "long long" test in pcrecpp_unittest when
186     HAVE_LONG_LONG is not defined.
187    
188 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
189 ph10 304 bring them up to date and include new features. This patch includes:
190 ph10 309
191 ph10 304 - Fixed PH's badly added libz and libbz2 support.
192     - Fixed a problem with static linking.
193 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
194 ph10 304 - Fixed dftables problem and added an option.
195     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
196     HAVE_LONG_LONG.
197     - Added readline support for pcretest.
198 ph10 309 - Added an listing of the option settings after cmake has run.
199    
200 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
201     "pcre.dll" under mingw when using Configure/Make. I added stuff to
202     Makefile.am that cause it to include this special target, without
203     affecting anything else. Note that the same mingw target plus all
204     the other distribution libraries and programs are now supported
205     when configuring with CMake (see 6 below) instead of with
206     Configure/Make.
207 ph10 309
208 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
209     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
210 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
211     solves the problem, but it does no harm.
212 ph10 313
213 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
214 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
215 ph10 314 with CMake, and also correct the comment about stack recursion.
216 ph10 313
217 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
218 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
219     of a program that users should build themselves after PCRE is installed, so
220     building it automatically is not really right. What is more, it gave
221 ph10 312 trouble in some build environments.
222 ph10 300
223 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
224 ph10 308
225 ph10 319
226 ph10 298 Version 7.5 10-Jan-08
227 ph10 263 ---------------------
228    
229     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
230     values in parens when parsing an RE using the C++ wrapper."
231 ph10 286
232 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
233     Characters greater than 255 were excluded from the class instead of being
234     included.
235 ph10 286
236     3. The same bug as (2) above applied to negated POSIX classes such as
237 ph10 265 [:^space:].
238 ph10 286
239 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
240     defined or documented. It seems to have been a typo for PCRE_STATIC, so
241 ph10 286 I have changed it.
242    
243 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
244 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
245     first named subpattern whose name started with "a" (in other words, the
246 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
247     expected" is now given for (?&) (a zero-length name), and this patch also
248     makes it give the same error for \k'' (previously it complained that that
249     was a reference to a non-existent subpattern).
250 ph10 286
251 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
252 ph10 286 this is right because (?- can be followed by option settings as well as by
253 ph10 269 digits. I have, however, made the messages clearer.
254 ph10 286
255 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
256     than the number used in the conditional) now cause a compile-time error.
257     This is actually not compatible with Perl, which accepts such patterns, but
258     treats the conditional as always being FALSE (as PCRE used to), but it
259     seems to me that giving a diagnostic is better.
260 ph10 286
261 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
262 ph10 275 and messages.
263 ph10 286
264     9. Fix two occurrences of "backslash" in comments that should have been
265     "backspace".
266    
267     10. Remove two redundant lines of code that can never be obeyed (their function
268     was moved elsewhere).
269    
270     11. The program that makes PCRE's Unicode character property table had a bug
271     which caused it to generate incorrect table entries for sequences of
272 ph10 277 characters that have the same character type, but are in different scripts.
273 ph10 286 It amalgamated them into a single range, with the script of the first of
274 ph10 277 them. In other words, some characters were in the wrong script. There were
275     thirteen such cases, affecting characters in the following ranges:
276 ph10 286
277 ph10 277 U+002b0 - U+002c1
278     U+0060c - U+0060d
279 ph10 286 U+0061e - U+00612
280 ph10 277 U+0064b - U+0065e
281     U+0074d - U+0076d
282     U+01800 - U+01805
283     U+01d00 - U+01d77
284     U+01d9b - U+01dbf
285     U+0200b - U+0200f
286     U+030fc - U+030fe
287     U+03260 - U+0327f
288     U+0fb46 - U+0fbb1
289     U+10450 - U+1049d
290 ph10 286
291 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
292     compatible with GNU grep in that, if there was more than one match in a
293     line, it showed only the first of them. It now behaves in the same way as
294     GNU grep.
295 ph10 286
296     13. If the -o and -v options were combined for pcregrep, it printed a blank
297     line for every non-matching line. GNU grep prints nothing, and pcregrep now
298     does the same. The return code can be used to tell if there were any
299     non-matching lines.
300    
301 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
302    
303     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
304 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
305 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
306     and both kinds of lookbehind were skipped).
307    
308 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
309 ph10 284 inclusion of <windows.h> to before rather than after the definition of
310     INVALID_FILE_ATTRIBUTES (patch from David Byron).
311 ph10 263
312 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
313 ph10 286 character property caused pcre_compile() to compile bad code, which led at
314     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
315     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
316     caused the error; without that there was no problem.
317 ph10 263
318 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
319 ph10 286
320 ph10 289 19. Added --enable-pcretest-libreadline.
321 ph10 286
322 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
323 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
324 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
325     later patch that removed the other one (the right fix) and added unit tests
326     that check the return values (which was not done before).
327 ph10 292
328 ph10 291 21. Several CMake things:
329 ph10 287
330 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
331 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
332 ph10 288
333 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
334     linked with the newly-built libraries, not previously installed ones.
335 ph10 291
336 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
337 ph10 298
338     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
339     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
340     UTF-8 newline character). The key issue is that the pattern starts .*;
341     this means that the match must be either at the beginning, or after a
342     newline. The bug was in the code for advancing after a failed match and
343     checking that the new position followed a newline. It was not taking
344 ph10 294 account of UTF-8 characters correctly.
345 ph10 298
346     23. PCRE was behaving differently from Perl in the way it recognized POSIX
347     character classes. PCRE was not treating the sequence [:...:] as a
348     character class unless the ... were all letters. Perl, however, seems to
349     allow any characters between [: and :], though of course it rejects as
350     unknown any "names" that contain non-letters, because all the known class
351     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
352     for example, whereas PCRE did not - it did not recognize a POSIX character
353     class. This seemed a bit dangerous, so the code has been changed to be
354     closer to Perl. The behaviour is not identical to Perl, because PCRE will
355     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
356     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
357     Perl does, and where it didn't before.
358    
359 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
360     Windows environments %n is disabled by default.
361 ph10 292
362    
363 ph10 260 Version 7.4 21-Sep-07
364 ph10 230 ---------------------
365    
366     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
367 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
368     LF". That isn't really right - the whole point of the change was to try to
369     help when there was an actual mention of one of the two characters. So now
370     the change happens only if \r or \n (or a literal CR or LF) character is
371 ph10 230 encountered.
372 ph10 231
373     2. The 32-bit options word was also used for 6 internal flags, but the numbers
374     of both had grown to the point where there were only 3 bits left.
375     Fortunately, there was spare space in the data structure, and so I have
376     moved the internal flags into a new 16-bit field to free up more option
377 ph10 230 bits.
378 ph10 231
379     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
380     but did not set the internal JCHANGED flag - either of these is enough to
381     control the way the "get" function works - but the PCRE_INFO_JCHANGED
382     facility is supposed to tell if (?J) was ever used, so now (?J) at the
383 ph10 230 start sets both bits.
384    
385 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
386     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
387 ph10 230
388 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
389    
390     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
391 ph10 233 compatibility, even though it is no longer used.
392 ph10 243
393     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
394 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
395 ph10 259 windows.h file is present (where different names are used). [This was
396 ph10 257 reversed later after testing - see 16 below.]
397 ph10 243
398     8. Changed all #include <config.h> to #include "config.h". There were also
399 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
400 ph10 243
401 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
402 ph10 243 sequence off the lines that it output.
403    
404     10. It was pointed out to me that arrays of string pointers cause lots of
405     relocations when a shared library is dynamically loaded. A technique of
406     using a single long string with a table of offsets can drastically reduce
407     these. I have refactored PCRE in four places to do this. The result is
408 ph10 240 dramatic:
409 ph10 243
410 ph10 240 Originally: 290
411     After changing UCP table: 187
412 ph10 243 After changing error message table: 43
413 ph10 240 After changing table of "verbs" 36
414     After changing table of Posix names 22
415 ph10 243
416 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
417 ph10 247
418 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
419 ph10 247 unicode-properties was also set.
420    
421 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
422 ph10 231
423 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
424     checked only for CRLF.
425 ph10 233
426 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
427    
428 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
429 ph10 253
430 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
431 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
432     entirely. This removes changes made in 7 above.
433 ph10 256
434 ph10 261 17. The CMake files have been updated, and there is now more information about
435     building with CMake in the NON-UNIX-USE document.
436 ph10 257
437 ph10 261
438 ph10 228 Version 7.3 28-Aug-07
439 ph10 157 ---------------------
440    
441 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
442     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
443     brackets there is not right, since it causes compilers to look for an
444     installed pcre.h, not the version that is in the source that is being
445     compiled (which of course may be different). I have changed it back to:
446 ph10 197
447 ph10 189 #include "pcre.h"
448 ph10 197
449     I have a vague recollection that the change was concerned with compiling in
450     different directories, but in the new build system, that is taken care of
451     by the VPATH setting the Makefile.
452    
453 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
454     when the subject happened to end in the byte 0x85 (e.g. if the last
455     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
456     characters but of course it shouldn't be taken as a newline when it is part
457     of another character. The bug was that, for an unlimited repeat of . in
458     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
459     characters when looking for a newline.
460 ph10 197
461     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
462    
463     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
464     in debug output.
465    
466 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
467     long printing in the pcrecpp unittest when running under MinGW.
468 ph10 189
469 ph10 197 6. ESC_K was left out of the EBCDIC table.
470 ph10 189
471 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
472     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
473     limit also applies to "virtual nesting" when a pattern is recursive, and in
474     this case 1000 isn't so big. I have been able to remove this limit at the
475     expense of backing off one optimization in certain circumstances. Normally,
476     when pcre_exec() would call its internal match() function recursively and
477     immediately return the result unconditionally, it uses a "tail recursion"
478     feature to save stack. However, when a subpattern that can match an empty
479     string has an unlimited repetition quantifier, it no longer makes this
480     optimization. That gives it a stack frame in which to save the data for
481     checking that an empty string has been matched. Previously this was taken
482     from the 1000-entry workspace that had been reserved. So now there is no
483     explicit limit, but more stack is used.
484 ph10 189
485 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
486     syntax that is required for Windows, and which was going wrong for the
487     pcreposix and pcrecpp parts of the library. These were overlooked when this
488     problem was solved for the main library.
489 ph10 197
490 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
491     the size of patterns that contain repeated groups with explicit upper
492     limits. As the maximum quantifier is 65535, the maximum group length was
493     set at 30,000 so that the product of these two numbers did not overflow a
494     32-bit integer. However, it turns out that people want to use groups that
495     are longer than 30,000 bytes (though not repeat them that many times).
496     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
497     made it possible to implement the integer overflow checks in a much more
498     dynamic way, which I have now done. The artificial limitation on group
499     length has been removed - we now have only the limit on the total length of
500     the compiled pattern, which depends on the LINK_SIZE setting.
501 ph10 208
502     10. Fixed a bug in the documentation for get/copy named substring when
503     duplicate names are permitted. If none of the named substrings are set, the
504     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
505     empty string.
506    
507     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
508     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
509     because the ] is interpreted as the first data character and the
510     terminating ] is not found. PCRE has been made compatible with Perl in this
511     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
512     cause memory overwriting.
513    
514 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
515     string has been matched (to stop an infinite loop). It was not recognizing
516 ph10 208 a conditional subpattern that could match an empty string if that
517 ph10 206 subpattern was within another subpattern. For example, it looped when
518 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
519 ph10 206 condition was not nested. This bug has been fixed.
520 ph10 208
521 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
522     past the start of the subject in the presence of bytes with the top bit
523     set, for example "\x8aBCD".
524 ph10 211
525 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
526     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
527 ph10 200
528 ph10 211 14. Optimized (?!) to (*FAIL).
529 ph10 202
530 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
531     This restricts code points to be within the range 0 to 0x10FFFF, excluding
532     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
533     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
534     does: it's just the validity check that is more restrictive.
535 ph10 220
536     16. Inserted checks for integer overflows during escape sequence (backslash)
537     processing, and also fixed erroneous offset values for syntax errors during
538     backslash processing.
539    
540 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
541 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
542    
543 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
544     caused an overrun.
545 ph10 220
546     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
547     something other than just ASCII characters) inside a group that had an
548     unlimited repeat caused a loop at compile time (while checking to see
549     whether the group could match an empty string).
550    
551 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
552     [\P{Any}] did so. (Error in the code for printing property names.)
553 ph10 210
554 ph10 220 21. An orphan \E inside a character class could cause a crash.
555    
556     22. A repeated capturing bracket such as (A)? could cause a wild memory
557 ph10 218 reference during compilation.
558 ph10 220
559     23. There are several functions in pcre_compile() that scan along a compiled
560     expression for various reasons (e.g. to see if it's fixed length for look
561 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
562 ph10 220 present in the pattern. These operators have additional parameters compared
563     with \d, etc, and these were not being taken into account when moving along
564 ph10 218 the compiled data. Specifically:
565 ph10 220
566     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
567     length.
568    
569     (b) An item such as \pL+ within a repeated group could cause crashes or
570 ph10 218 loops.
571 ph10 220
572 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
573 ph10 220 "reference to non-existent subpattern" error.
574    
575 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
576    
577 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
578 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
579 ph10 211
580 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
581 ph10 218
582 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
583 ph10 223 character were causing crashes (broken optimization).
584 ph10 227
585 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
586 ph10 227 \p or \P) caused a compile-time loop.
587    
588 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
589     break. For example, the unstudied pattern [\r\n]A does not match the string
590     "\r\nA" because change 7.0/46 below moves the current point on by two
591     characters after failing to match at the start. However, the pattern \nA
592 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
593     the same is true. There doesn't seem any very clean way out of this, but
594     what I have chosen to do makes the common cases work: PCRE now takes note
595     of whether there can be an explicit match for \r or \n anywhere in the
596     pattern, and if so, 7.0/46 no longer applies. As part of this change,
597     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
598     pattern has explicit CR or LF references.
599 ph10 222
600 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
601 ph10 223
602 ph10 227
603 ph10 189 Version 7.2 19-Jun-07
604     ---------------------
605    
606 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
607     which is apparently normally available under Windows.
608 ph10 159
609     2. Re-jig the pcregrep tests with different newline settings in an attempt
610     to make them independent of the local environment's newline setting.
611 ph10 157
612 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
613 ph10 165
614 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
615     was not 2, because the output contained actual offsets. The recent new
616 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
617     usable with all link sizes.
618    
619 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
620     stack recursion. This gives a massive performance boost under BSD, but just
621 ph10 165 a small improvement under Linux. However, it saves one field in the frame
622 ph10 164 in all cases.
623 ph10 172
624 ph10 166 6. Added more features from the forthcoming Perl 5.10:
625 ph10 172
626 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
627     recursion call. It refers to the nth most recently opened parentheses.
628 ph10 172
629 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
630 ph10 172 to be opened parentheses.
631    
632     (c) Conditions that refer to capturing parentheses can be specified
633 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
634 ph10 172
635 ph10 168 (d) \K resets the start of the current match so that everything before
636 ph10 172 is not part of it.
637    
638 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
639 ph10 172
640 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
641 ph10 172 reference syntax.
642 ph10 182
643 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
644 ph10 182 alternative starts with the same number.
645 ph10 172
646 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
647    
648 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
649     PCRE_INFO_JCHANGED.
650    
651     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
652     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
653 ph10 170 for detecting groups that can match an empty string.
654 ph10 159
655 ph10 172 9. A pattern with a very large number of alternatives (more than several
656     hundred) was running out of internal workspace during the pre-compile
657     phase, where pcre_compile() figures out how much memory will be needed. A
658     bit of new cunning has reduced the workspace needed for groups with
659     alternatives. The 1000-alternative test pattern now uses 12 bytes of
660     workspace instead of running out of the 4096 that are available.
661 ph10 182
662 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
663 ph10 172
664 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
665     The report of the bug said:
666 ph10 182
667 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
668     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
669 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
670 ph10 185
671 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
672 ph10 185 it matched the wrong number of bytes.
673 ph10 172
674 ph10 179
675 ph10 155 Version 7.1 24-Apr-07
676 ph10 98 ---------------------
677    
678 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
679 ph10 122 that is more "standard", making use of automake and other Autotools. There
680 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
681     on this.
682 ph10 111
683     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
684     for recursive directory scanning broke on some systems because the files
685     are not scanned in any specific order and on different systems the order
686     was different. A call to "sort" has been inserted into RunGrepTest for the
687     approprate test as a short-term fix. In the longer term there may be an
688 ph10 100 alternative.
689 ph10 111
690 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
691 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
692     people do their own conversions for various reasons). The problems
693     concerned the use of low-level troff macros .br and .in. I have therefore
694     removed all such uses from the man pages (some were redundant, some could
695 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
696     HTML has been updated to handle .nf/.fi and to complain if it encounters
697     .br or .in.
698 ph10 111
699 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
700 ph10 123 arranged for config.h to be included in the distribution, with the name
701 ph10 111 config.h.generic, for the benefit of those who have to compile without
702     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
703    
704     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
705     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
706 ph10 127 makevp.bat for the current PCRE, using the additional files
707 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
708 ph10 111
709     6. A Windows user reported a minor discrepancy with test 2, which turned out
710     to be caused by a trailing space on an input line that had got lost in his
711 ph10 102 copy. The trailing space was an accident, so I've just removed it.
712 ph10 111
713 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
714 ph10 111 that is needed.
715    
716 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
717     as "const" (a) because they are and (b) because it helps the PHP
718     maintainers who have recently made a script to detect big data structures
719 ph10 111 in the php code that should be moved to the .rodata section. I remembered
720     to update Builducptable as well, so it won't revert if ucptable.h is ever
721 ph10 105 re-created.
722 ph10 111
723     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
724 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
725 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
726     support is not required. This saves 1.5-2K of code, which is important in
727 ph10 107 some applications.
728 ph10 111
729 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
730 ph10 111 so as not to refer to the tables, even though these functions will never be
731     called when UTF-8 support is disabled. Otherwise there are problems with a
732     shared library.
733    
734 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
735    
736     (a) It was defining its arguments as char * instead of void *.
737    
738 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
739     a long time ago when I wrote it, but is no longer the case.
740    
741 ph10 118 The emulated memove() is provided for those environments that have neither
742 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
743 ph10 118 is clearly not the case, as these two bugs were recently reported.
744 ph10 123
745 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
746 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
747     pages, and it removes trailing spaces from listed files. It also creates
748     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
749     case, it wraps all the #defines with #ifndefs. This script should be run
750 ph10 111 before "make dist".
751 ph10 123
752 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
753     with Unicode property support.
754 ph10 123
755     (a) For a maximizing quantifier, if the two different cases of the
756     character were of different lengths in their UTF-8 codings (there are
757     some cases like this - I found 11), and the matching function had to
758 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
759     were both the same length.
760 ph10 123
761     (b) When PCRE was configured to use the heap rather than the stack for
762     recursion during matching, it was not correctly preserving the data for
763     the other case of a UTF-8 character when checking ahead for a match
764     while processing a minimizing repeat. If the check also involved
765 ph10 115 matching a wide character, but failed, corruption could cause an
766     erroneous result when trying to check for a repeat of the original
767     character.
768 ph10 123
769 ph10 116 13. Some tidying changes to the testing mechanism:
770 ph10 98
771 ph10 116 (a) The RunTest script now detects the internal link size and whether there
772     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
773 ph10 123 values substituted by "configure". (The RunGrepTest script already did
774     this for UTF-8.) The configure.ac script no longer substitutes the
775     relevant variables.
776    
777 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
778     with length and offset values. This means that the output is different
779     for different internal link sizes. Test 2 is skipped for link sizes
780     other than 2 because of this, bypassing the problem. Unfortunately,
781     there was also a test in test 3 (the locale tests) that used /B and
782 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
783     I have added a new /Z option to pcretest that replaces the length and
784     offset values with spaces. This is now used to make test 3 independent
785 ph10 122 of link size. (Test 2 will be tidied up later.)
786 ph10 123
787     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
788 ph10 122 segmentation fault instead of returning the appropriate error message.
789 ph10 134
790 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
791 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
792     This doesn't seem right; it now treats the CRLF combination as the line
793     ending, and so does not match in that case. It's only a pattern such as ^$
794     that would hit this one: something like ^ABC$ would have failed after \r
795     and then tried again after \r\n.
796    
797 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
798 ph10 134 in an attempt to make files that differ only in their line terminators
799     compare equal. This works on Linux.
800 ph10 142
801 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
802     as it exited. This is now fixed, thanks to valgrind.
803 ph10 142
804 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
805 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
806     was because its rules for how to advance for /g after matching an empty
807 ph10 143 string at the end of a line did not allow for this case. They now check for
808     it specially.
809 ph10 150
810     20. pcretest is supposed to handle patterns and data of any length, by
811     extending its buffers when necessary. It was getting this wrong when the
812 ph10 147 buffer for a data line had to be extended.
813 ph10 150
814 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
815 ph10 150 CRLF as a newline sequence.
816 ph10 152
817 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
818 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
819     I have nevertheless tidied it up.
820 ph10 111
821 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
822 ph10 123
823 ph10 153 24. Added a man page for pcre-config.
824 ph10 152
825 ph10 153
826 nigel 93 Version 7.0 19-Dec-06
827     ---------------------
828    
829     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
830     moving to gcc 4.1.1.
831    
832     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
833     sys/time.h, which is documented as needed for this function. It doesn't
834     seem to matter on Linux, but it showed up on some releases of OS X.
835    
836     3. It seems that there are systems where bytes whose values are greater than
837     127 match isprint() in the "C" locale. The "C" locale should be the
838     default when a C program starts up. In most systems, only ASCII printing
839     characters match isprint(). This difference caused the output from pcretest
840     to vary, making some of the tests fail. I have changed pcretest so that:
841    
842     (a) When it is outputting text in the compiled version of a pattern, bytes
843     other than 32-126 are always shown as hex escapes.
844    
845     (b) When it is outputting text that is a matched part of a subject string,
846     it does the same, unless a different locale has been set for the match
847     (using the /L modifier). In this case, it uses isprint() to decide.
848    
849     4. Fixed a major bug that caused incorrect computation of the amount of memory
850     required for a compiled pattern when options that changed within the
851     pattern affected the logic of the preliminary scan that determines the
852     length. The relevant options are -x, and -i in UTF-8 mode. The result was
853     that the computed length was too small. The symptoms of this bug were
854     either the PCRE error "internal error: code overflow" from pcre_compile(),
855     or a glibc crash with a message such as "pcretest: free(): invalid next
856     size (fast)". Examples of patterns that provoked this bug (shown in
857     pcretest format) are:
858    
859     /(?-x: )/x
860     /(?x)(?-x: \s*#\s*)/
861     /((?i)[\x{c0}])/8
862     /(?i:[\x{c0}])/8
863    
864     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
865     is now done differently.
866    
867     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
868     wrapper classes; (b) implement a new function in the C++ scanner that is
869     more efficient than the old way of doing things because it avoids levels of
870     recursion in the regex matching; (c) add a paragraph to the documentation
871     for the FullMatch() function.
872    
873     6. The escape sequence \n was being treated as whatever was defined as
874     "newline". Not only was this contrary to the documentation, which states
875     that \n is character 10 (hex 0A), but it also went horribly wrong when
876     "newline" was defined as CRLF. This has been fixed.
877    
878     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
879     was being set to -1 for the "end of line" case (supposedly a value that no
880     character can have). Though this value is never used (the check for end of
881     line is "zero bytes in current character"), it caused compiler complaints.
882     I've changed it to 0xffffffff.
883    
884     8. In pcre_version.c, the version string was being built by a sequence of
885     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
886     string (as it is for production releases) called a macro with an empty
887     argument. The C standard says the result of this is undefined. The gcc
888     compiler treats it as an empty string (which was what was wanted) but it is
889     reported that Visual C gives an error. The source has been hacked around to
890     avoid this problem.
891    
892     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
893     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
894     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
895     of them did).
896    
897     10. Originally, pcretest opened its input and output without "b"; then I was
898     told that "b" was needed in some environments, so it was added for release
899     5.0 to both the input and output. (It makes no difference on Unix-like
900     systems.) Later I was told that it is wrong for the input on Windows. I've
901     now abstracted the modes into two macros, to make it easier to fiddle with
902     them, and removed "b" from the input mode under Windows.
903    
904     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
905    
906     12. Added -help and --help to pcretest as an official way of being reminded
907     of the options.
908    
909     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
910     and pcrecpp.cc because they annoy compilers at high warning levels.
911    
912     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
913    
914     15. Fixed an occurrence of == in configure.ac that should have been = (shell
915     scripts are not C programs :-) and which was not noticed because it works
916     on Linux.
917    
918     16. pcretest is supposed to handle any length of pattern and data line (as one
919     line or as a continued sequence of lines) by extending its input buffer if
920     necessary. This feature was broken for very long pattern lines, leading to
921     a string of junk being passed to pcre_compile() if the pattern was longer
922     than about 50K.
923    
924     17. I have done a major re-factoring of the way pcre_compile() computes the
925     amount of memory needed for a compiled pattern. Previously, there was code
926     that made a preliminary scan of the pattern in order to do this. That was
927     OK when PCRE was new, but as the facilities have expanded, it has become
928     harder and harder to keep it in step with the real compile phase, and there
929     have been a number of bugs (see for example, 4 above). I have now found a
930     cunning way of running the real compile function in a "fake" mode that
931     enables it to compute how much memory it would need, while actually only
932     ever using a few hundred bytes of working memory and without too many
933     tests of the mode. This should make future maintenance and development
934     easier. A side effect of this work is that the limit of 200 on the nesting
935     depth of parentheses has been removed (though this was never a serious
936     limitation, I suspect). However, there is a downside: pcre_compile() now
937     runs more slowly than before (30% or more, depending on the pattern). I
938     hope this isn't a big issue. There is no effect on runtime performance.
939    
940     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
941     newline (only possible for the last line of a file) and it was a
942     pattern that set a locale (followed by /Lsomething), pcretest crashed.
943    
944     19. Added additional timing features to pcretest. (1) The -tm option now times
945     matching only, not compiling. (2) Both -t and -tm can be followed, as a
946     separate command line item, by a number that specifies the number of
947     repeats to use when timing. The default is 50000; this gives better
948     precision, but takes uncomfortably long for very large patterns.
949    
950     20. Extended pcre_study() to be more clever in cases where a branch of a
951     subpattern has no definite first character. For example, (a*|b*)[cd] would
952     previously give no result from pcre_study(). Now it recognizes that the
953     first character must be a, b, c, or d.
954    
955     21. There was an incorrect error "recursive call could loop indefinitely" if
956     a subpattern (or the entire pattern) that was being tested for matching an
957     empty string contained only one non-empty item after a nested subpattern.
958     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
959     incorrectly, because the \d was being skipped in the check.
960    
961     22. The pcretest program now has a new pattern option /B and a command line
962     option -b, which is equivalent to adding /B to every pattern. This causes
963     it to show the compiled bytecode, without the additional information that
964     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
965     is the same as /B/I).
966    
967     23. A new optimization is now able automatically to treat some sequences such
968     as a*b as a*+b. More specifically, if something simple (such as a character
969     or a simple class like \d) has an unlimited quantifier, and is followed by
970     something that cannot possibly match the quantified thing, the quantifier
971     is automatically "possessified".
972    
973     24. A recursive reference to a subpattern whose number was greater than 39
974     went wrong under certain circumstances in UTF-8 mode. This bug could also
975     have affected the operation of pcre_study().
976    
977     25. Realized that a little bit of performance could be had by replacing
978     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
979    
980     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
981    
982     27. Possessive quantifiers such as a++ were previously implemented by turning
983     them into atomic groups such as ($>a+). Now they have their own opcodes,
984     which improves performance. This includes the automatically created ones
985     from 23 above.
986    
987     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
988     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
989     the first matched character to be a colon. This applied both to named and
990     numbered groups.
991    
992     29. The ucpinternal.h header file was missing its idempotency #ifdef.
993    
994     30. I was sent a "project" file called libpcre.a.dev which I understand makes
995     building PCRE on Windows easier, so I have included it in the distribution.
996    
997     31. There is now a check in pcretest against a ridiculously large number being
998     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
999     loop, the loop is abandoned.
1000    
1001     32. Forward references to subpatterns in conditions such as (?(2)...) where
1002     subpattern 2 is defined later cause pcre_compile() to search forwards in
1003     the pattern for the relevant set of parentheses. This search went wrong
1004     when there were unescaped parentheses in a character class, parentheses
1005     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1006    
1007     33. "Subroutine" calls and backreferences were previously restricted to
1008     referencing subpatterns earlier in the regex. This restriction has now
1009     been removed.
1010    
1011     34. Added a number of extra features that are going to be in Perl 5.10. On the
1012     whole, these are just syntactic alternatives for features that PCRE had
1013     previously implemented using the Python syntax or my own invention. The
1014     other formats are all retained for compatibility.
1015    
1016     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1017     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1018     also .NET compatible.
1019    
1020     (b) A recursion or subroutine call to a named group can now be defined as
1021     (?&name) as well as (?P>name).
1022    
1023     (c) A backreference to a named group can now be defined as \k<name> or
1024     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1025     5.10, are also .NET compatible.
1026    
1027     (d) A conditional reference to a named group can now use the syntax
1028     (?(<name>) or (?('name') as well as (?(name).
1029    
1030     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1031     groups (named and numbered) that are never evaluated inline, but can be
1032     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1033     is always false. There may be only one alternative in such a group.
1034    
1035     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1036     as the simple (?(R). The condition is true only if the most recent
1037     recursion is that of the given number or name. It does not search out
1038     through the entire recursion stack.
1039    
1040     (g) The escape \gN or \g{N} has been added, where N is a positive or
1041     negative number, specifying an absolute or relative reference.
1042    
1043     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1044     some "unreachable code" warnings.
1045    
1046     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1047     things, this adds five new scripts.
1048    
1049     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1050     There were also incompatibilities regarding the handling of \Q..\E inside
1051     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1052     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1053    
1054     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1055     matches an empty string, and forcibly breaks the loop. There were bugs in
1056     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1057     against aaaa the result was just "a" rather than "aaaa", for example. Two
1058     separate and independent bugs (that affected different cases) have been
1059     fixed.
1060    
1061     39. Refactored the code to abolish the use of different opcodes for small
1062     capturing bracket numbers. This is a tidy that I avoided doing when I
1063     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1064     The new approach is not only tidier, it makes it possible to reduce the
1065     memory needed to fix the previous bug (38).
1066    
1067     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1068     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1069     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1070     mode.
1071    
1072     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1073     report.
1074    
1075     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1076     copy construction and assignment in the C++ wrapper.
1077    
1078     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1079     couple of bugs that could have given wrong results in the "--newline=crlf"
1080     case.
1081    
1082     44. Added a number of casts and did some reorganization of signed/unsigned int
1083     variables following suggestions from Dair Grant. Also renamed the variable
1084     "this" as "item" because it is a C++ keyword.
1085    
1086     45. Arranged for dftables to add
1087    
1088     #include "pcre_internal.h"
1089    
1090     to pcre_chartables.c because without it, gcc 4.x may remove the array
1091     definition from the final binary if PCRE is built into a static library and
1092     dead code stripping is activated.
1093    
1094     46. For an unanchored pattern, if a match attempt fails at the start of a
1095     newline sequence, and the newline setting is CRLF or ANY, and the next two
1096     characters are CRLF, advance by two characters instead of one.
1097    
1098    
1099 nigel 91 Version 6.7 04-Jul-06
1100     ---------------------
1101    
1102     1. In order to handle tests when input lines are enormously long, pcretest has
1103     been re-factored so that it automatically extends its buffers when
1104     necessary. The code is crude, but this _is_ just a test program. The
1105     default size has been increased from 32K to 50K.
1106    
1107     2. The code in pcre_study() was using the value of the re argument before
1108     testing it for NULL. (Of course, in any sensible call of the function, it
1109     won't be NULL.)
1110    
1111     3. The memmove() emulation function in pcre_internal.h, which is used on
1112     systems that lack both memmove() and bcopy() - that is, hardly ever -
1113     was missing a "static" storage class specifier.
1114    
1115     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1116     containing an extended class (one that cannot be represented by a bitmap
1117     because it contains high-valued characters or Unicode property items, e.g.
1118     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1119     pattern, but PCRE should not loop if you do not (it no longer does).
1120     [Detail: two cases were found: (a) a repeated subpattern containing an
1121     extended class; (b) a recursive reference to a subpattern that followed a
1122     previous extended class. It wasn't skipping over the extended class
1123     correctly when UTF-8 mode was not set.]
1124    
1125     5. A negated single-character class was not being recognized as fixed-length
1126     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1127     compile error "lookbehind assertion is not fixed length".
1128    
1129     6. The RunPerlTest auxiliary script was showing an unexpected difference
1130     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1131     write a Perl script that can interpret lines of an input file either as
1132     byte characters or as UTF-8, which is what "perltest" was being required to
1133     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1134     can't do is switch easily at run time between having the "use utf8;" pragma
1135     or not. In the end, I fudged it by using the RunPerlTest script to insert
1136     "use utf8;" explicitly for the UTF-8 tests.
1137    
1138     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1139     the end of the subject string, contrary to the documentation and to what
1140     Perl does. This was true of both matching functions. Now it matches only at
1141     the start of the subject and immediately after *internal* newlines.
1142    
1143     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1144     a pointer to an int instead of a pointer to an unsigned long int. This
1145     caused problems on 64-bit systems.
1146    
1147     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1148     instance of the 'standard' template library not being so standard".
1149    
1150     10. There was no check on the number of named subpatterns nor the maximum
1151     length of a subpattern name. The product of these values is used to compute
1152     the size of the memory block for a compiled pattern. By supplying a very
1153     long subpattern name and a large number of named subpatterns, the size
1154     computation could be caused to overflow. This is now prevented by limiting
1155     the length of names to 32 characters, and the number of named subpatterns
1156     to 10,000.
1157    
1158     11. Subpatterns that are repeated with specific counts have to be replicated in
1159     the compiled pattern. The size of memory for this was computed from the
1160     length of the subpattern and the repeat count. The latter is limited to
1161     65535, but there was no limit on the former, meaning that integer overflow
1162     could in principle occur. The compiled length of a repeated subpattern is
1163     now limited to 30,000 bytes in order to prevent this.
1164    
1165     12. Added the optional facility to have named substrings with the same name.
1166    
1167     13. Added the ability to use a named substring as a condition, using the
1168     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1169     are numbers (not recommended). Forward references are permitted.
1170    
1171     14. Added forward references in named backreferences (if you see what I mean).
1172    
1173     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1174     pattern could run off the end of the subject. For example, the pattern
1175     "(?s)(.{1,5})"8 did this with the subject "ab".
1176    
1177     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1178     PCRE_CASELESS was set when matching characters that were quantified with ?
1179     or *.
1180    
1181     17. A character class other than a single negated character that had a minimum
1182     but no maximum quantifier - for example [ab]{6,} - was not handled
1183     correctly by pce_dfa_exec(). It would match only one character.
1184    
1185     18. A valid (though odd) pattern that looked like a POSIX character
1186     class but used an invalid character after [ (for example [[,abc,]]) caused
1187     pcre_compile() to give the error "Failed: internal error: code overflow" or
1188     in some cases to crash with a glibc free() error. This could even happen if
1189     the pattern terminated after [[ but there just happened to be a sequence of
1190     letters, a binary zero, and a closing ] in the memory that followed.
1191    
1192     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1193     over the years. Originally (before any Unicode support), just the bottom 8
1194     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1195     output from "man perlunicode" includes this:
1196    
1197     The regular expression compiler produces polymorphic opcodes. That
1198     is, the pattern adapts to the data and automatically switches to
1199     the Unicode character scheme when presented with Unicode data--or
1200     instead uses a traditional byte scheme when presented with byte
1201     data.
1202    
1203     Sadly, a wide octal escape does not cause a switch, and in a string with
1204     no other multibyte characters, these octal escapes are treated as before.
1205     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1206     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1207     Unicode string.
1208    
1209     I have not perpetrated such confusion in PCRE. Up till now, it took just
1210     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1211     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1212     translate to the appropriate multibyte character.
1213    
1214     29. Applied some refactoring to reduce the number of warnings from Microsoft
1215     and Borland compilers. This has included removing the fudge introduced
1216     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1217     a warning about an unused variable.
1218    
1219     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1220     characters since release 4.0, because Perl (from release 5.004) does not.
1221     [Or at least, is documented not to: some releases seem to be in conflict
1222     with the documentation.] However, when a pattern was studied with
1223     pcre_study() and all its branches started with \s, PCRE still included VT
1224     as a possible starting character. Of course, this did no harm; it just
1225     caused an unnecessary match attempt.
1226    
1227     22. Removed a now-redundant internal flag bit that recorded the fact that case
1228     dependency changed within the pattern. This was once needed for "required
1229     byte" processing, but is no longer used. This recovers a now-scarce options
1230     bit. Also moved the least significant internal flag bit to the most-
1231     significant bit of the word, which was not previously used (hangover from
1232     the days when it was an int rather than a uint) to free up another bit for
1233     the future.
1234    
1235     23. Added support for CRLF line endings as well as CR and LF. As well as the
1236     default being selectable at build time, it can now be changed at runtime
1237     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1238     specify that it is scanning data with non-default line endings.
1239    
1240     24. Changed the definition of CXXLINK to make it agree with the definition of
1241     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1242    
1243     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1244     recursions. This makes a big different to stack usage for some patterns.
1245    
1246     26. If a subpattern containing a named recursion or subroutine reference such
1247     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1248     the space required for the compiled pattern went wrong and gave too small a
1249     value. Depending on the environment, this could lead to "Failed: internal
1250     error: code overflow at offset 49" or "glibc detected double free or
1251     corruption" errors.
1252    
1253     27. Applied patches from Google (a) to support the new newline modes and (b) to
1254     advance over multibyte UTF-8 characters in GlobalReplace.
1255    
1256     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1257     difference for some implementation of PCRE in some Windows version.
1258    
1259     29. Added some extra testing facilities to pcretest:
1260    
1261     \q<number> in a data line sets the "match limit" value
1262     \Q<number> in a data line sets the "match recursion limt" value
1263     -S <number> sets the stack size, where <number> is in megabytes
1264    
1265     The -S option isn't available for Windows.
1266    
1267    
1268 nigel 89 Version 6.6 06-Feb-06
1269     ---------------------
1270    
1271     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1272     in pcreposix.h. I have copied the definition from pcre.h.
1273    
1274     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1275     because pcre.h is no longer a built file.
1276    
1277     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1278     not normally included in the compiled code.
1279    
1280    
1281 nigel 87 Version 6.5 01-Feb-06
1282     ---------------------
1283    
1284     1. When using the partial match feature with pcre_dfa_exec(), it was not
1285     anchoring the second and subsequent partial matches at the new starting
1286     point. This could lead to incorrect results. For example, with the pattern
1287     /1234/, partially matching against "123" and then "a4" gave a match.
1288    
1289     2. Changes to pcregrep:
1290    
1291     (a) All non-match returns from pcre_exec() were being treated as failures
1292     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1293     error message is output. Some extra information is given for the
1294     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1295     probably the only errors that are likely to be caused by users (by
1296     specifying a regex that has nested indefinite repeats, for instance).
1297     If there are more than 20 of these errors, pcregrep is abandoned.
1298    
1299     (b) A binary zero was treated as data while matching, but terminated the
1300     output line if it was written out. This has been fixed: binary zeroes
1301     are now no different to any other data bytes.
1302    
1303     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1304     used to set a locale for matching. The --locale=xxxx long option has
1305     been added (no short equivalent) to specify a locale explicitly on the
1306     pcregrep command, overriding the environment variables.
1307    
1308     (d) When -B was used with -n, some line numbers in the output were one less
1309     than they should have been.
1310    
1311     (e) Added the -o (--only-matching) option.
1312    
1313     (f) If -A or -C was used with -c (count only), some lines of context were
1314     accidentally printed for the final match.
1315    
1316     (g) Added the -H (--with-filename) option.
1317    
1318     (h) The combination of options -rh failed to suppress file names for files
1319     that were found from directory arguments.
1320    
1321     (i) Added the -D (--devices) and -d (--directories) options.
1322    
1323     (j) Added the -F (--fixed-strings) option.
1324    
1325     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1326    
1327     (l) Added the --colo(u)r option.
1328    
1329     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1330     is not present by default.
1331    
1332     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1333     items such as (?R) or (?1), when the recursion could match a number of
1334     alternatives. If it matched one of the alternatives, but subsequently,
1335     outside the recursion, there was a failure, the code tried to back up into
1336     the recursion. However, because of the way PCRE is implemented, this is not
1337     possible, and the result was an incorrect result from the match.
1338    
1339     In order to prevent this happening, the specification of recursion has
1340     been changed so that all such subpatterns are automatically treated as
1341     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1342    
1343     4. I had overlooked the fact that, in some locales, there are characters for
1344     which isalpha() is true but neither isupper() nor islower() are true. In
1345     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1346     and ordfeminine) are like this. This affected the treatment of \w and \W
1347     when they appeared in character classes, but not when they appeared outside
1348     a character class. The bit map for "word" characters is now created
1349     separately from the results of isalnum() instead of just taking it from the
1350     upper, lower, and digit maps. (Plus the underscore character, of course.)
1351    
1352     5. The above bug also affected the handling of POSIX character classes such as
1353     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1354     permanent tables. Instead, the bit maps for such a class were previously
1355     created as the appropriate unions of the upper, lower, and digit bitmaps.
1356     Now they are created by subtraction from the [[:word:]] class, which has
1357     its own bitmap.
1358    
1359     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1360     It is created by subtracting the vertical space characters (\x09, \x0a,
1361     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1362     subtraction was done in the overall bitmap for a character class, meaning
1363     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1364     be recognized. This bug has been fixed.
1365    
1366     7. Patches from the folks at Google:
1367    
1368     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1369     real life, but is still worth protecting against".
1370    
1371     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1372     regular expressions".
1373    
1374     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1375     have it.
1376    
1377     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1378     "configure" and the latter not, in order to fix a problem somebody had
1379     with compiling the Arg class on HP-UX.
1380    
1381     (e) Improve the error-handling of the C++ wrapper a little bit.
1382    
1383     (f) New tests for checking recursion limiting.
1384    
1385     8. The pcre_memmove() function, which is used only if the environment does not
1386     have a standard memmove() function (and is therefore rarely compiled),
1387     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1388     returning a result (though PCRE never actually uses the result).
1389    
1390     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1391     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1392     returned instead of calling malloc() with an overflowing number that would
1393     most likely cause subsequent chaos.
1394    
1395     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1396    
1397     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1398     with this option is matched, the nmatch and pmatch options of regexec() are
1399     ignored.
1400    
1401     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1402     provided in case anyone wants to the the POSIX interface with UTF-8
1403     strings.
1404    
1405     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1406     C++ linking (needed for some HP-UX environments).
1407    
1408     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1409     (unused parameter) and in the pcre_printint() function (omitted "default"
1410     switch label when the default is to do nothing).
1411    
1412     15. Added some code to make it possible, when PCRE is compiled as a C++
1413     library, to replace subject pointers for pcre_exec() with a smart pointer
1414     class, thus making it possible to process discontinuous strings.
1415    
1416     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1417     much the same function. They were added by different people who were trying
1418     to make PCRE easy to compile on non-Unix systems. It has been suggested
1419     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1420     for compiling on Windows systems. I have therefore replaced it with
1421     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1422     defaults to "extern" for C or "extern C" for C++, which works fine on
1423     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1424     SCOPE with something explicit in config.h. In addition:
1425    
1426     (a) pcreposix.h still had just "extern" instead of either of these macros;
1427     I have replaced it with PCRE_DATA_SCOPE.
1428    
1429     (b) Functions such as _pcre_xclass(), which are internal to the library,
1430     but external in the C sense, all had PCRE_EXPORT in their definitions.
1431     This is apparently wrong for the Windows case, so I have removed it.
1432     (It makes no difference on Unix-like systems.)
1433    
1434     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1435     of recursive calls to match(). This is different to MATCH_LIMIT because
1436     that limits the total number of calls to match(), not all of which increase
1437     the depth of recursion. Limiting the recursion depth limits the amount of
1438     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1439     when PCRE is compiled, and changed at run time. A patch from Google adds
1440     this functionality to the C++ interface.
1441    
1442     18. Changes to the handling of Unicode character properties:
1443    
1444     (a) Updated the table to Unicode 4.1.0.
1445    
1446     (b) Recognize characters that are not in the table as "Cn" (undefined).
1447    
1448     (c) I revised the way the table is implemented to a much improved format
1449     which includes recognition of ranges. It now supports the ranges that
1450     are defined in UnicodeData.txt, and it also amalgamates other
1451     characters into ranges. This has reduced the number of entries in the
1452     table from around 16,000 to around 3,000, thus reducing its size
1453     considerably. I realized I did not need to use a tree structure after
1454     all - a binary chop search is just as efficient. Having reduced the
1455     number of entries, I extended their size from 6 bytes to 8 bytes to
1456     allow for more data.
1457    
1458     (d) Added support for Unicode script names via properties such as \p{Han}.
1459    
1460     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1461     matching that character.
1462    
1463     20. When matching a repeated Unicode property with a minimum greater than zero,
1464     (for example \pL{2,}), PCRE could look past the end of the subject if it
1465     reached it while seeking the minimum number of characters. This could
1466     happen only if some of the characters were more than one byte long, because
1467     there is a check for at least the minimum number of bytes.
1468    
1469     21. Refactored the implementation of \p and \P so as to be more general, to
1470     allow for more different types of property in future. This has changed the
1471     compiled form incompatibly. Anybody with saved compiled patterns that use
1472     \p or \P will have to recompile them.
1473    
1474     22. Added "Any" and "L&" to the supported property types.
1475    
1476     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1477     but give a compile time error if the value is greater than 0xff.
1478    
1479     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1480     accidentally not being installed or uninstalled.
1481    
1482     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1483     made were to insert the current release number. This seemed silly, because
1484     it made things harder for people building PCRE on systems that don't run
1485     "configure". I have turned pcre.h into a distributed file, no longer built
1486     by "configure", with the version identification directly included. There is
1487     no longer a pcre.h.in file.
1488    
1489     However, this change necessitated a change to the pcre-config script as
1490     well. It is built from pcre-config.in, and one of the substitutions was the
1491     release number. I have updated configure.ac so that ./configure now finds
1492     the release number by grepping pcre.h.
1493    
1494     26. Added the ability to run the tests under valgrind.
1495    
1496    
1497 nigel 85 Version 6.4 05-Sep-05
1498     ---------------------
1499    
1500     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1501     "--" to be printed when multiple files were scanned, even when none of the
1502     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1503     consider it to be a bug, and have restored the previous behaviour.
1504    
1505     2. A couple of code tidies to get rid of compiler warnings.
1506    
1507     3. The pcretest program used to cheat by referring to symbols in the library
1508     whose names begin with _pcre_. These are internal symbols that are not
1509     really supposed to be visible externally, and in some environments it is
1510     possible to suppress them. The cheating is now confined to including
1511     certain files from the library's source, which is a bit cleaner.
1512    
1513     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1514     file's purpose clearer.
1515    
1516     5. Reorganized pcre_ucp_findchar().
1517    
1518    
1519 nigel 83 Version 6.3 15-Aug-05
1520     ---------------------
1521    
1522     1. The file libpcre.pc.in did not have general read permission in the tarball.
1523    
1524     2. There were some problems when building without C++ support:
1525    
1526     (a) If C++ support was not built, "make install" and "make test" still
1527     tried to test it.
1528    
1529     (b) There were problems when the value of CXX was explicitly set. Some
1530     changes have been made to try to fix these, and ...
1531    
1532     (c) --disable-cpp can now be used to explicitly disable C++ support.
1533    
1534     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1535     backslash in a target when C++ was disabled. This confuses some
1536     versions of "make", apparently. Using an intermediate variable solves
1537     this. (Same for CPP_LOBJ.)
1538    
1539     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1540     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1541     necessary on certain architectures.
1542    
1543     4. Added a setting of -export-symbols-regex to the link command to remove
1544     those symbols that are exported in the C sense, but actually are local
1545     within the library, and not documented. Their names all begin with
1546     "_pcre_". This is not a perfect job, because (a) we have to except some
1547     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1548     available (and never for static libraries). I have made a note to try to
1549     find a way round (a) in the future.
1550    
1551    
1552 nigel 81 Version 6.2 01-Aug-05
1553     ---------------------
1554    
1555     1. There was no test for integer overflow of quantifier values. A construction
1556     such as {1111111111111111} would give undefined results. What is worse, if
1557     a minimum quantifier for a parenthesized subpattern overflowed and became
1558     negative, the calculation of the memory size went wrong. This could have
1559     led to memory overwriting.
1560    
1561     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1562    
1563     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1564     operating environments where this matters.
1565    
1566     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1567     PCRE options from within the C++ wrapper.
1568    
1569     5. Named capturing subpatterns were not being correctly counted when a pattern
1570     was compiled. This caused two problems: (a) If there were more than 100
1571     such subpatterns, the calculation of the memory needed for the whole
1572     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1573     back references of the form \12, where the number was greater than 9, were
1574     not recognized as back references, even though there were sufficient
1575     previous subpatterns.
1576    
1577     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1578     versions of gcc, e.g. 2.95.4.
1579    
1580    
1581 nigel 79 Version 6.1 21-Jun-05
1582     ---------------------
1583    
1584     1. There was one reference to the variable "posix" in pcretest.c that was not
1585     surrounded by "#if !defined NOPOSIX".
1586    
1587     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1588     the cross-check on the old pcre_info() function, for the benefit of the
1589     cut-down version of PCRE that is currently imported into Exim.
1590    
1591     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1592     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1593     patterns that start (?i) but I don't think that matters. The use of (?i) is
1594     just an example; this all applies to the other options as well.
1595    
1596     4. Since libtool seems to echo the compile commands it is issuing, the output
1597     from "make" can be reduced a bit by putting "@" in front of each libtool
1598     compile command.
1599    
1600     5. Patch from the folks at Google for configure.in to be a bit more thorough
1601     in checking for a suitable C++ installation before trying to compile the
1602     C++ stuff. This should fix a reported problem when a compiler was present,
1603     but no suitable headers.
1604    
1605     6. The man pages all had just "PCRE" as their title. I have changed them to
1606     be the relevant file name. I have also arranged that these names are
1607     retained in the file doc/pcre.txt, which is a concatenation in text format
1608     of all the man pages except the little individual ones for each function.
1609    
1610     7. The NON-UNIX-USE file had not been updated for the different set of source
1611     files that come with release 6. I also added a few comments about the C++
1612     wrapper.
1613    
1614    
1615 nigel 77 Version 6.0 07-Jun-05
1616     ---------------------
1617    
1618     1. Some minor internal re-organization to help with my DFA experiments.
1619    
1620     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1621     didn't matter for the library itself when fully configured, but did matter
1622     when compiling without UCP support, or within Exim, where the ucp files are
1623     not imported.
1624    
1625     3. Refactoring of the library code to split up the various functions into
1626     different source modules. The addition of the new DFA matching code (see
1627     below) to a single monolithic source would have made it really too
1628     unwieldy, quite apart from causing all the code to be include in a
1629     statically linked application, when only some functions are used. This is
1630     relevant even without the DFA addition now that patterns can be compiled in
1631     one application and matched in another.
1632    
1633     The downside of splitting up is that there have to be some external
1634     functions and data tables that are used internally in different modules of
1635     the library but which are not part of the API. These have all had their
1636     names changed to start with "_pcre_" so that they are unlikely to clash
1637     with other external names.
1638    
1639     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1640     a different (DFA) algorithm. Although it is slower than the original
1641     function, it does have some advantages for certain types of matching
1642     problem.
1643    
1644     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1645     including restarting after a partial match.
1646    
1647     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1648     defined when compiling for Windows was sent to me. I have put it into the
1649     code, though I have no means of testing or verifying it.
1650    
1651     7. Added the pcre_refcount() auxiliary function.
1652    
1653     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1654     match before or at the first newline in the subject string. In pcretest,
1655     the /f option on a pattern can be used to set this.
1656    
1657     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1658     would behave wrongly. This has been present in PCRE since release 4.0.
1659    
1660     10. A number of changes to the pcregrep command:
1661    
1662     (a) Refactored how -x works; insert ^(...)$ instead of setting
1663     PCRE_ANCHORED and checking the length, in preparation for adding
1664     something similar for -w.
1665    
1666     (b) Added the -w (match as a word) option.
1667    
1668     (c) Refactored the way lines are read and buffered so as to have more
1669     than one at a time available.
1670    
1671     (d) Implemented a pcregrep test script.
1672    
1673     (e) Added the -M (multiline match) option. This allows patterns to match
1674     over several lines of the subject. The buffering ensures that at least
1675     8K, or the rest of the document (whichever is the shorter) is available
1676     for matching (and similarly the previous 8K for lookbehind assertions).
1677    
1678     (f) Changed the --help output so that it now says
1679    
1680     -w, --word-regex(p)
1681    
1682     instead of two lines, one with "regex" and the other with "regexp"
1683     because that confused at least one person since the short forms are the
1684     same. (This required a bit of code, as the output is generated
1685     automatically from a table. It wasn't just a text change.)
1686    
1687     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1688     option but starts with a hyphen. Could be a pattern or a path name
1689     starting with a hyphen, for instance.
1690    
1691     (h) "-" can be given as a file name to represent stdin.
1692    
1693     (i) When file names are being printed, "(standard input)" is used for
1694     the standard input, for compatibility with GNU grep. Previously
1695     "<stdin>" was used.
1696    
1697     (j) The option --label=xxx can be used to supply a name to be used for
1698     stdin when file names are being printed. There is no short form.
1699    
1700     (k) Re-factored the options decoding logic because we are going to add
1701     two more options that take data. Such options can now be given in four
1702     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1703    
1704     (l) Added the -A, -B, and -C options for requesting that lines of context
1705     around matches be printed.
1706    
1707     (m) Added the -L option to print the names of files that do not contain
1708     any matching lines, that is, the complement of -l.
1709    
1710     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1711     continue to scan other files.
1712    
1713     (o) The -s option was incorrectly implemented. For compatibility with other
1714     greps, it now suppresses the error message for a non-existent or non-
1715     accessible file (but not the return code). There is a new option called
1716     -q that suppresses the output of matching lines, which was what -s was
1717     previously doing.
1718    
1719     (p) Added --include and --exclude options to specify files for inclusion
1720     and exclusion when recursing.
1721    
1722     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1723     Hopefully, it now does.
1724    
1725     12. Missing cast in pcre_study().
1726    
1727     13. Added an "uninstall" target to the makefile.
1728    
1729     14. Replaced "extern" in the function prototypes in Makefile.in with
1730     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1731     world, but is set differently for Windows.
1732    
1733     15. Added a second compiling function called pcre_compile2(). The only
1734     difference is that it has an extra argument, which is a pointer to an
1735     integer error code. When there is a compile-time failure, this is set
1736     non-zero, in addition to the error test pointer being set to point to an
1737     error message. The new argument may be NULL if no error number is required
1738     (but then you may as well call pcre_compile(), which is now just a
1739     wrapper). This facility is provided because some applications need a
1740     numeric error indication, but it has also enabled me to tidy up the way
1741     compile-time errors are handled in the POSIX wrapper.
1742    
1743     16. Added VPATH=.libs to the makefile; this should help when building with one
1744     prefix path and installing with another. (Or so I'm told by someone who
1745     knows more about this stuff than I do.)
1746    
1747     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1748     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1749     match everything, including newlines. This is not POSIX-compatible, but
1750     somebody wanted the feature. From pcretest it can be activated by using
1751     both the P and the s flags.
1752    
1753     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1754    
1755     19. libpcre.pc was being incorrectly installed as executable.
1756    
1757     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1758     it now also looks for '\r' so that it will work unmodified on Windows.
1759    
1760     21. Added Google's contributed C++ wrapper to the distribution.
1761    
1762     22. Added some untidy missing memory free() calls in pcretest, to keep
1763     Electric Fence happy when testing.
1764    
1765    
1766    
1767 nigel 75 Version 5.0 13-Sep-04
1768     ---------------------
1769    
1770     1. Internal change: literal characters are no longer packed up into items
1771     containing multiple characters in a single byte-string. Each character
1772     is now matched using a separate opcode. However, there may be more than one
1773     byte in the character in UTF-8 mode.
1774    
1775     2. The pcre_callout_block structure has two new fields: pattern_position and
1776     next_item_length. These contain the offset in the pattern to the next match
1777     item, and its length, respectively.
1778    
1779     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1780     insertion of callouts before each pattern item. Added the /C option to
1781     pcretest to make use of this.
1782    
1783     4. On the advice of a Windows user, the lines
1784    
1785     #if defined(_WIN32) || defined(WIN32)
1786     _setmode( _fileno( stdout ), 0x8000 );
1787     #endif /* defined(_WIN32) || defined(WIN32) */
1788    
1789     have been added to the source of pcretest. This apparently does useful
1790     magic in relation to line terminators.
1791    
1792     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1793     for the benefit of those environments where the "b" makes a difference.
1794    
1795     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1796     to know about it. I have put a hack into configure.in that adds in code
1797     to set GCC=yes if CC=icc. This seems to end up at a point in the
1798     generated configure script that is early enough to affect the setting of
1799     compiler options, which is what is needed, but I have no means of testing
1800     whether it really works. (The user who reported this had patched the
1801     generated configure script, which of course I cannot do.)
1802    
1803     LATER: After change 22 below (new libtool files), the configure script
1804     seems to know about icc (and also ecc). Therefore, I have commented out
1805     this hack in configure.in.
1806    
1807     7. Added support for pkg-config (2 patches were sent in).
1808    
1809     8. Negated POSIX character classes that used a combination of internal tables
1810     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1811     [[:^ascii]]. Typically, they would match almost any characters. The other
1812     POSIX classes were not broken in this way.
1813    
1814     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1815     to find the match, as PCRE was deluded into thinking that the match had to
1816     start at the start point or following a newline. The same bug applied to
1817     patterns with negative forward assertions or any backward assertions
1818     preceding ".*" at the start, unless the pattern required a fixed first
1819     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1820    
1821     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1822     starting at the last subject character, bytes beyond the end of the subject
1823     string were read.
1824    
1825     11. Renamed the variable "class" as "classbits" to make life easier for C++
1826     users. (Previously there was a macro definition, but it apparently wasn't
1827     enough.)
1828    
1829     12. Added the new field "tables" to the extra data so that tables can be passed
1830     in at exec time, or the internal tables can be re-selected. This allows
1831     a compiled regex to be saved and re-used at a later time by a different
1832     program that might have everything at different addresses.
1833    
1834     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1835     -R library as well as a -L library.
1836    
1837     14. The debugging options of pcretest (-d on the command line or D on a
1838     pattern) showed incorrect output for anything following an extended class
1839     that contained multibyte characters and which was followed by a quantifier.
1840    
1841     15. Added optional support for general category Unicode character properties
1842     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1843     support. It adds about 90K to the size of the library. The meanings of the
1844     inbuilt class escapes such as \d and \s have NOT been changed.
1845    
1846     16. Updated pcredemo.c to include calls to free() to release the memory for the
1847     compiled pattern.
1848    
1849     17. The generated file chartables.c was being created in the source directory
1850     instead of in the building directory. This caused the build to fail if the
1851     source directory was different from the building directory, and was
1852     read-only.
1853    
1854     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1855     file. No doubt somebody will tell me if they don't make sense... Also added
1856     Dan Mooney's comments about building on OpenVMS.
1857    
1858     19. Added support for partial matching via the PCRE_PARTIAL option for
1859     pcre_exec() and the \P data escape in pcretest.
1860    
1861     20. Extended pcretest with 3 new pattern features:
1862    
1863     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1864     write the compiled pattern to the file whose name is "rest-of-line".
1865     This is a straight binary dump of the data, with the saved pointer to
1866     the character tables forced to be NULL. The study data, if any, is
1867     written too. After writing, pcretest reads a new pattern.
1868    
1869     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1870     compiled pattern from the given file. There must not be any
1871     occurrences of "<" in the file name (pretty unlikely); if there are,
1872     pcretest will instead treat the initial "<" as a pattern delimiter.
1873     After reading in the pattern, pcretest goes on to read data lines as
1874     usual.
1875    
1876     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1877     and 16-bit fields in a compiled pattern, to simulate a pattern that
1878     was compiled on a host of opposite endianness.
1879    
1880     21. The pcre-exec() function can now cope with patterns that were compiled on
1881     hosts of opposite endianness, with this restriction:
1882    
1883     As for any compiled expression that is saved and used later, the tables
1884     pointer field cannot be preserved; the extra_data field in the arguments
1885     to pcre_exec() should be used to pass in a tables address if a value
1886     other than the default internal tables were used at compile time.
1887    
1888     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1889     now diagnosed as an error. Previously, most of the time, a negative number
1890     would have been treated as zero, but if in addition "ovector" was passed as
1891     NULL, a crash could occur.
1892    
1893     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1894     new versions from the libtool 1.5 distribution (the last one is a copy of
1895     a file called libtool.m4). This seems to have fixed the need to patch
1896     "configure" to support Darwin 1.3 (which I used to do). However, I still
1897     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1898     workstation).
1899    
1900     24. Changed the PCRE licence to be the more standard "BSD" licence.
1901    
1902    
1903 nigel 73 Version 4.5 01-Dec-03
1904     ---------------------
1905    
1906     1. There has been some re-arrangement of the code for the match() function so
1907     that it can be compiled in a version that does not call itself recursively.
1908     Instead, it keeps those local variables that need separate instances for
1909     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1910     needs to "recurse". Keeping track of where control must go is done by means
1911     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1912     hide most of the details from the main code, and operates only if
1913     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1914     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1915     operating.
1916    
1917     To make it easier for callers to provide specially tailored get/free
1918     functions for this usage, two new functions, pcre_stack_malloc, and
1919     pcre_stack_free, are used. They are always called in strict stacking order,
1920     and the size of block requested is always the same.
1921    
1922     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1923     PCRE has been compiled to use the stack or the heap for recursion. The
1924     -C option of pcretest uses this to show which version is compiled.
1925    
1926     A new data escape \S, is added to pcretest; it causes the amounts of store
1927     obtained and freed by both kinds of malloc/free at match time to be added
1928     to the output.
1929    
1930     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1931     what's available on my current Linux desktop machine.
1932    
1933     3. When matching a UTF-8 string, the test for a valid string at the start has
1934     been extended. If start_offset is not zero, PCRE now checks that it points
1935     to a byte that is the start of a UTF-8 character. If not, it returns
1936     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1937     this is necessary because there may be backward assertions in the pattern.
1938     When matching the same subject several times, it may save resources to use
1939     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1940    
1941     4. The code for checking the validity of UTF-8 strings has been tightened so
1942     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1943     containing "overlong sequences".
1944    
1945     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1946     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1947     should have been "&", but it just so happened that all the cases this let
1948     through by mistake were picked up later in the function.
1949    
1950     6. I had used a variable called "isblank" - this is a C99 function, causing
1951     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1952    
1953     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1954     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1955     so the version is shown; (c) stop "make test" echoing "./RunTest".
1956    
1957     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1958    
1959     9. The prototype for memmove() for systems that don't have it was using
1960     size_t, but the inclusion of the header that defines size_t was later. I've
1961     moved the #includes for the C headers earlier to avoid this.
1962    
1963     10. Added some adjustments to the code to make it easier to compiler on certain
1964     special systems:
1965    
1966     (a) Some "const" qualifiers were missing.
1967     (b) Added the macro EXPORT before all exported functions; by default this
1968     is defined to be empty.
1969     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1970     that it reads its output file name as an argument instead of writing
1971     to the standard output and assuming this can be redirected.
1972    
1973     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1974     class containing characters with values greater than 255, PCRE compilation
1975     went into a loop.
1976    
1977     12. A recursive reference to a subpattern that was within another subpattern
1978     that had a minimum quantifier of zero caused PCRE to crash. For example,
1979     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1980     recursion. If the recursively-called subpattern itself had a zero repeat,
1981     that was OK.
1982    
1983     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1984     buffer into which it was copied (for escape processing) was still set at
1985     1024, so long lines caused crashes.
1986    
1987     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1988     "internal error: code overflow...". This applied to any character class
1989     that was followed by a possessive quantifier.
1990    
1991     15. Modified the Makefile to add libpcre.la as a prerequisite for
1992     libpcreposix.la because I was told this is needed for a parallel build to
1993     work.
1994    
1995     16. If a pattern that contained .* following optional items at the start was
1996     studied, the wrong optimizing data was generated, leading to matching
1997     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1998     matching string must start with a or b or c. The correct conclusion for
1999     this pattern is that a match can start with any character.
2000    
2001    
2002 nigel 71 Version 4.4 13-Aug-03
2003     ---------------------
2004    
2005     1. In UTF-8 mode, a character class containing characters with values between
2006     127 and 255 was not handled correctly if the compiled pattern was studied.
2007     In fixing this, I have also improved the studying algorithm for such
2008     classes (slightly).
2009    
2010     2. Three internal functions had redundant arguments passed to them. Removal
2011     might give a very teeny performance improvement.
2012    
2013     3. Documentation bug: the value of the capture_top field in a callout is *one
2014     more than* the number of the hightest numbered captured substring.
2015    
2016     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2017     in incorrectly linking with a previously installed version. They now link
2018     explicitly with libpcre.la.
2019    
2020     5. configure.in no longer needs to recognize Cygwin specially.
2021    
2022     6. A problem in pcre.in for Windows platforms is fixed.
2023    
2024     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2025     pcretest, it used to include the size of the study block as part of its
2026     output. Unfortunately, the structure contains a field that has a different
2027     size on different hardware architectures. This meant that the tests that
2028     showed this size failed. As the block is currently always of a fixed size,
2029     this information isn't actually particularly useful in pcretest output, so
2030     I have just removed it.
2031    
2032     8. Three pre-processor statements accidentally did not start in column 1.
2033     Sadly, there are *still* compilers around that complain, even though
2034     standard C has not required this for well over a decade. Sigh.
2035    
2036     9. In pcretest, the code for checking callouts passed small integers in the
2037     callout_data field, which is a void * field. However, some picky compilers
2038     complained about the casts involved for this on 64-bit systems. Now
2039     pcretest passes the address of the small integer instead, which should get
2040     rid of the warnings.
2041    
2042     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2043     both compile and run time, and gives an error if an invalid UTF-8 sequence
2044     is found. There is a option for disabling this check in cases where the
2045     string is known to be correct and/or the maximum performance is wanted.
2046    
2047     11. In response to a bug report, I changed one line in Makefile.in from
2048    
2049     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2050     to
2051     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2052    
2053     to look similar to other lines, but I have no way of telling whether this
2054     is the right thing to do, as I do not use Windows. No doubt I'll get told
2055     if it's wrong...
2056    
2057    
2058 nigel 69 Version 4.3 21-May-03
2059     ---------------------
2060    
2061     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2062     Makefile.
2063    
2064     2. Some refactoring to improve the quality of the code:
2065    
2066     (i) The utf8_table... variables are now declared "const".
2067    
2068     (ii) The code for \cx, which used the "case flipping" table to upper case
2069     lower case letters, now just substracts 32. This is ASCII-specific,
2070     but the whole concept of \cx is ASCII-specific, so it seems
2071     reasonable.
2072    
2073     (iii) PCRE was using its character types table to recognize decimal and
2074     hexadecimal digits in the pattern. This is silly, because it handles
2075     only 0-9, a-f, and A-F, but the character types table is locale-
2076     specific, which means strange things might happen. A private
2077     table is now used for this - though it costs 256 bytes, a table is
2078     much faster than multiple explicit tests. Of course, the standard
2079     character types table is still used for matching digits in subject
2080     strings against \d.
2081    
2082     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2083     ending in _t are). So I've renamed it as ESC_tee.
2084    
2085     3. The first argument for regexec() in the POSIX wrapper should have been
2086     defined as "const".
2087    
2088     4. Changed pcretest to use malloc() for its buffers so that they can be
2089     Electric Fenced for debugging.
2090    
2091     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2092     to read one or more bytes before the start of the subject string. Often this
2093     had no effect on PCRE's behaviour, but in some circumstances it could
2094     provoke a segmentation fault.
2095    
2096     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2097     to try to read one or more bytes before the start of the subject string.
2098    
2099     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2100     UTF-8 support could misbehave in various ways if the subject string
2101     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2102     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2103     back over UTF-8 characters.)
2104    
2105    
2106 nigel 67 Version 4.2 14-Apr-03
2107     ---------------------
2108    
2109     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2110    
2111     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2112     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2113     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2114     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2115     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2116     and BUILD_EXEEXT
2117     Note: automatic setting of the BUILD variables is not yet working
2118     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2119     compile-time but not at link-time
2120     [LINK]: use for linking executables only
2121     make different versions for Windows and non-Windows
2122     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2123     libraries
2124     [LINK_FOR_BUILD]: new variable
2125     [OBJEXT]: use throughout
2126     [EXEEXT]: use throughout
2127     <winshared>: new target
2128     <wininstall>: new target
2129     <dftables.o>: use native compiler
2130     <dftables>: use native linker
2131     <install>: handle Windows platform correctly
2132     <clean>: ditto
2133     <check>: ditto
2134     copy DLL to top builddir before testing
2135    
2136     As part of these changes, -no-undefined was removed again. This was reported
2137     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2138     in any case.
2139    
2140     3. Some tidies to get rid of compiler warnings:
2141    
2142     . In the match_data structure, match_limit was an unsigned long int, whereas
2143     match_call_count was an int. I've made them both unsigned long ints.
2144    
2145     . In pcretest the fact that a const uschar * doesn't automatically cast to
2146     a void * provoked a warning.
2147    
2148     . Turning on some more compiler warnings threw up some "shadow" variables
2149     and a few more missing casts.
2150    
2151     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2152     option, a class that contained a single character with a value between 128
2153     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2154    
2155     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2156     option, a class that contained several characters, but with at least one
2157     whose value was between 128 and 255 caused PCRE to crash.
2158    
2159    
2160 nigel 65 Version 4.1 12-Mar-03
2161     ---------------------
2162 nigel 63
2163 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2164     needed, and a string in dftables.c that was longer than standard compilers are
2165     required to support.
2166    
2167     2. Compiling with Sun's compiler found a few more places where the code could
2168     be tidied up in order to avoid warnings.
2169    
2170     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2171     first of these names is deprecated in the latest Autoconf in favour of the name
2172     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2173     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2174     analogy I have changed it to CFLAGS_FOR_BUILD.
2175    
2176     4. Added -no-undefined to the linking command in the Makefile, because this is
2177     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2178     linking step for the pcreposix library.
2179    
2180     5. PCRE was failing to diagnose the case of two named groups with the same
2181     name.
2182    
2183     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2184     literal character that is needed in the subject for a match, and scans along to
2185     ensure that it is present before embarking on the full matching process. This
2186     saves time in cases of nested unlimited repeats that are never going to match.
2187     Problem: the scan can take a lot of time if the subject is very long (e.g.
2188     megabytes), thus penalizing straightforward matches. It is now done only if the
2189     amount of subject to be scanned is less than 1000 bytes.
2190    
2191     7. A lesser problem with the same optimization is that it was recording the
2192     first character of an anchored pattern as "needed", thus provoking a search
2193     right along the subject, even when the first match of the pattern was going to
2194     fail. The "needed" character is now not set for anchored patterns, unless it
2195     follows something in the pattern that is of non-fixed length. Thus, it still
2196     fulfils its original purpose of finding quick non-matches in cases of nested
2197     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2198    
2199    
2200     Version 4.0 17-Feb-03
2201     ---------------------
2202    
2203 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2204     extended to the end of string, PCRE compiled incorrect data. This could lead to
2205     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2206    
2207     2. Moved to autoconf 2.53 and libtool 1.4.2.
2208    
2209     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2210     the special perltest8 script is no longer needed - all the tests can be run
2211     from a single perltest script.
2212    
2213     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2214     by \s. It has now been removed in PCRE. This means it isn't recognized as
2215     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2216     class [:space:] *does* include VT, thereby creating a mess.
2217    
2218     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2219     space and tab.
2220    
2221     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2222     its new features into the main test script, reducing the number of scripts.
2223    
2224     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2225     were backward compatible, and made the (?i) apply to the whole pattern, as if
2226     /i were given. Now it behaves more logically, and applies the option setting
2227     only to what follows. PCRE has been changed to follow suit. However, if it
2228     finds options settings right at the start of the pattern, it extracts them into
2229     the global options, as before. Thus, they show up in the info data.
2230    
2231     8. Added support for the \Q...\E escape sequence. Characters in between are
2232     treated as literals. This is slightly different from Perl in that $ and @ are
2233     also handled as literals inside the quotes. In Perl, they will cause variable
2234     interpolation. Note the following examples:
2235    
2236     Pattern PCRE matches Perl matches
2237    
2238     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2239     \Qabc\$xyz\E abc\$xyz abc\$xyz
2240     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2241    
2242     For compatibility with Perl, \Q...\E sequences are recognized inside character
2243     classes as well as outside them.
2244    
2245     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2246     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2247     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2248     signed/unsigned warnings.
2249    
2250     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2251     option for pcretest, so I've replaced it by a simple function that does just
2252     that job.
2253    
2254     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2255     "pcregrep -".
2256    
2257     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2258     Java package. This provides some syntactic sugar for simple cases of what my
2259     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2260     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2261     item, you can use this simplified notation. Note that only makes sense with
2262     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2263     greediness, whatever the setting of the PCRE_UNGREEDY option.
2264    
2265     13. A change of greediness default within a pattern was not taking effect at
2266     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2267     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2268     was abstracted outside.
2269    
2270     14. PCRE now supports the \G assertion. It is true when the current matching
2271     position is at the start point of the match. This differs from \A when the
2272     starting offset is non-zero. Used with the /g option of pcretest (or similar
2273     code), it works in the same way as it does for Perl's /g option. If all
2274     alternatives of a regex begin with \G, the expression is anchored to the start
2275     match position, and the "anchored" flag is set in the compiled expression.
2276    
2277     15. Some bugs concerning the handling of certain option changes within patterns
2278     have been fixed. These applied to options other than (?ims). For example,
2279     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2280     been the other way round. Some of this was related to change 7 above.
2281    
2282     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2283     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2284     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2285     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2286    
2287     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2288     mode. Unlike ".", it always matches newline, whatever the setting of
2289     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2290     assertions. Perl allows it, but it doesn't (in general) work because it can't
2291     calculate the length of the lookbehind. At least, that's the case for Perl
2292     5.8.0 - I've been told they are going to document that it doesn't work in
2293     future.
2294    
2295     18. Added an error diagnosis for escapes that PCRE does not support: these are
2296     \L, \l, \N, \P, \p, \U, \u, and \X.
2297    
2298     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2299     reading past the end of the pattern in cases such as /[abcd/.
2300    
2301     20. PCRE was getting more memory than necessary for patterns with classes that
2302     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2303    
2304     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2305     compiling PCRE for use with Virtual Pascal.
2306    
2307     22. Small fix to the Makefile to make it work properly if the build is done
2308     outside the source tree.
2309    
2310     23. Added a new extension: a condition to go with recursion. If a conditional
2311     subpattern starts with (?(R) the "true" branch is used if recursion has
2312     happened, whereas the "false" branch is used only at the top level.
2313    
2314     24. When there was a very long string of literal characters (over 255 bytes
2315     without UTF support, over 250 bytes with UTF support), the computation of how
2316     much memory was required could be incorrect, leading to segfaults or other
2317     strange effects.
2318    
2319     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2320     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2321     there was a subsequent back reference to those brackets. This meant that, for
2322     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2323     possible to check for precisely this case. All we can do is abandon the
2324     optimization if .* occurs inside capturing brackets when there are any back
2325     references whatsoever. (See below for a better fix that came later.)
2326    
2327     26. The handling of the optimization for finding the first character of a
2328     non-anchored pattern, and for finding a character that is required later in the
2329     match were failing in some cases. This didn't break the matching; it just
2330     failed to optimize when it could. The way this is done has been re-implemented.
2331    
2332     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2333    
2334     28. Added a new feature that provides some of the functionality that Perl
2335     provides with (?{...}). The facility is termed a "callout". The way it is done
2336     in PCRE is for the caller to provide an optional function, by setting
2337     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2338     global variable. By default it is unset, which disables all calling out. To get
2339     the function called, the regex must include (?C) at appropriate points. This
2340     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2341     This provides a means of identifying different callout points. When PCRE
2342     reaches such a point in the regex, if pcre_callout has been set, the external
2343     function is called. It is provided with data in a structure called
2344     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2345     matching continues; if it returns a non-zero value, the match at the current
2346     point fails. However, backtracking will occur if possible. [This was changed
2347     later and other features added - see item 49 below.]
2348    
2349     29. pcretest is upgraded to test the callout functionality. It provides a
2350     callout function that displays information. By default, it shows the start of
2351     the match and the current position in the text. There are some new data escapes
2352     to vary what happens:
2353    
2354     \C+ in addition, show current contents of captured substrings
2355     \C- do not supply a callout function
2356     \C!n return 1 when callout number n is reached
2357     \C!n!m return 1 when callout number n is reached for the mth time
2358    
2359     30. If pcregrep was called with the -l option and just a single file name, it
2360     output "<stdin>" if a match was found, instead of the file name.
2361    
2362     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2363     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2364     pcre_exec(). This saves a malloc/free per call. The default value of
2365     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2366     when configuring.
2367    
2368     32. The default maximum size of a compiled pattern is 64K. There have been a
2369     few cases of people hitting this limit. The code now uses macros to handle the
2370     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2371     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2372     configuring. Tests 2 and 5 work only with 2-byte links because they output
2373     debugging information about compiled patterns.
2374    
2375     33. Internal code re-arrangements:
2376    
2377     (a) Moved the debugging function for printing out a compiled regex into
2378     its own source file (printint.c) and used #include to pull it into
2379     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2380     separate copies.
2381    
2382     (b) Defined the list of op-code names for debugging as a macro in
2383     internal.h so that it is next to the definition of the opcodes.
2384    
2385     (c) Defined a table of op-code lengths for simpler skipping along compiled
2386     code. This is again a macro in internal.h so that it is next to the
2387     definition of the opcodes.
2388    
2389     34. Added support for recursive calls to individual subpatterns, along the
2390     lines of Robin Houston's patch (but implemented somewhat differently).
2391    
2392     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2393     allow it to read and process whole directories in Win32. This code was
2394     contributed by Lionel Fourquaux; it has not been tested by me.
2395    
2396     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2397     used to name a group. Names consist of alphanumerics and underscores, and must
2398     be unique. Back references use the syntax (?P=name) and recursive calls use
2399     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2400     numbers. The function pcre_fullinfo() can be used after compilation to extract
2401     a name/number map. There are three relevant calls:
2402    
2403     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2404     PCRE_INFO_NAMECOUNT yields the number of entries
2405     PCRE_INFO_NAMETABLE yields a pointer to the map.
2406    
2407     The map is a vector of fixed-size entries. The size of each entry depends on
2408     the length of the longest name used. The first two bytes of each entry are the
2409     group number, most significant byte first. There follows the corresponding
2410     name, zero terminated. The names are in alphabetical order.
2411    
2412     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2413     case instead of 255. Making it the same both with and without UTF-8 support
2414     means that the same test output works with both.
2415    
2416     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2417     calling malloc() with a zero argument.
2418    
2419     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2420     optimization. I've improved things by keeping a bitmap of backreferences with
2421     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2422     fact referenced, the optimization can be applied. It is unlikely that a
2423     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2424     the match to follow \n) will appear inside brackets with a number greater than
2425     31, but if it does, any back reference > 31 suppresses the optimization.
2426    
2427     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2428     of disabling numbered capturing parentheses. Any opening parenthesis that is
2429     not followed by ? behaves as if it were followed by ?: but named parentheses
2430     can still be used for capturing (and they will acquire numbers in the usual
2431     way).
2432    
2433     41. Redesigned the return codes from the match() function into yes/no/error so
2434     that errors can be passed back from deep inside the nested calls. A malloc
2435     failure while inside a recursive subpattern call now causes the
2436     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2437    
2438     42. It is now possible to set a limit on the number of times the match()
2439     function is called in a call to pcre_exec(). This facility makes it possible to
2440     limit the amount of recursion and backtracking, though not in a directly
2441     obvious way, because the match() function is used in a number of different
2442     circumstances. The count starts from zero for each position in the subject
2443     string (for non-anchored patterns). The default limit is, for compatibility, a
2444     large number, namely 10 000 000. You can change this in two ways:
2445    
2446     (a) When configuring PCRE before making, you can use --with-match-limit=n
2447     to set a default value for the compiled library.
2448    
2449     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2450     a different value is set. See 45 below.
2451    
2452     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2453    
2454     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2455     of things that can be changed at compile time. The first argument specifies
2456     what is wanted and the second points to where the information is to be placed.
2457     The current list of available information is:
2458    
2459     PCRE_CONFIG_UTF8
2460    
2461     The output is an integer that is set to one if UTF-8 support is available;
2462     otherwise it is set to zero.
2463    
2464     PCRE_CONFIG_NEWLINE
2465    
2466     The output is an integer that it set to the value of the code that is used for
2467     newline. It is either LF (10) or CR (13).
2468    
2469     PCRE_CONFIG_LINK_SIZE
2470    
2471     The output is an integer that contains the number of bytes used for internal
2472     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2473    
2474     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2475    
2476     The output is an integer that contains the threshold above which the POSIX
2477     interface uses malloc() for output vectors. See item 31 above.
2478    
2479     PCRE_CONFIG_MATCH_LIMIT
2480    
2481     The output is an unsigned integer that contains the default limit of the number
2482     of match() calls in a pcre_exec() execution. See 42 above.
2483    
2484     44. pcretest has been upgraded by the addition of the -C option. This causes it
2485     to extract all the available output from the new pcre_config() function, and to
2486     output it. The program then exits immediately.
2487    
2488     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2489     order to support additional features. One way would have been to define
2490     pcre_exec2() (for example) with extra arguments, but this would not have been
2491     extensible, and would also have required all calls to the original function to
2492     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2493     is used for passing in "extra" data from pcre_study().
2494    
2495     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2496     contains the following fields:
2497    
2498     flags a bitmap indicating which of the following fields are set
2499     study_data opaque data from pcre_study()
2500     match_limit a way of specifying a limit on match() calls for a specific
2501     call to pcre_exec()
2502     callout_data data for callouts (see 49 below)
2503    
2504     The flag bits are also defined in pcre.h, and are
2505    
2506     PCRE_EXTRA_STUDY_DATA
2507     PCRE_EXTRA_MATCH_LIMIT
2508     PCRE_EXTRA_CALLOUT_DATA
2509    
2510     The pcre_study() function now returns one of these new pcre_extra blocks, with
2511     the actual study data pointed to by the study_data field, and the
2512     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2513     before. That is, this change is entirely upwards-compatible and requires no
2514     change to existing code.
2515    
2516     If you want to pass in additional data to pcre_exec(), you can either place it
2517     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2518     block.
2519    
2520     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2521     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2522     times with different match limits, until it finds the minimum value needed for
2523     pcre_exec() to complete. The value is then output. This can be instructive; for
2524     most simple matches the number is quite small, but for pathological cases it
2525     gets very large very quickly.
2526    
2527     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2528     returns the size of the data block pointed to by the study_data field in a
2529     pcre_extra block, that is, the value that was passed as the argument to
2530     pcre_malloc() when PCRE was getting memory in which to place the information
2531     created by pcre_study(). The fourth argument should point to a size_t variable.
2532     pcretest has been extended so that this information is shown after a successful
2533     pcre_study() call when information about the compiled regex is being displayed.
2534    
2535     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2536     because what follows is always an absolute path. (Later: it turns out that this
2537     is more than cosmetic for MinGW, because it doesn't like empty path
2538     components.)
2539    
2540     49. Some changes have been made to the callout feature (see 28 above):
2541    
2542     (i) A callout function now has three choices for what it returns:
2543    
2544     0 => success, carry on matching
2545     > 0 => failure at this point, but backtrack if possible
2546     < 0 => serious error, return this value from pcre_exec()
2547    
2548     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2549     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2550     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2551     use by callout functions. It will never be used by PCRE itself.
2552    
2553     (ii) The pcre_extra structure (see 45 above) has a void * field called
2554     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2555     pcre_callout_block structure has a field of the same name. The contents of
2556     the field passed in the pcre_extra structure are passed to the callout
2557     function in the corresponding field in the callout block. This makes it
2558     easier to use the same callout-containing regex from multiple threads. For
2559     testing, the pcretest program has a new data escape
2560    
2561     \C*n pass the number n (may be negative) as callout_data
2562    
2563     If the callout function in pcretest receives a non-zero value as
2564     callout_data, it returns that value.
2565    
2566     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2567     there were some redundant $(CFLAGS) in commands that are now specified as
2568     $(LINK), which already includes $(CFLAGS).
2569    
2570     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2571     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2572     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2573     one-byte characters throughout. Note that case-insensitive matching applies
2574     only to characters whose values are less than 256. PCRE doesn't support the
2575     notion of cases for higher-valued characters.
2576    
2577     (i) A character class whose characters are all within 0-255 is handled as
2578     a bit map, and the map is inverted for negative classes. Previously, a
2579     character > 255 always failed to match such a class; however it should
2580     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2581    
2582     (ii) A negated character class with a single character < 255 is coded as
2583     "not this character" (OP_NOT). This wasn't working properly when the test
2584     character was multibyte, either singly or repeated.
2585    
2586     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2587     mode, for example: \x{100}{2,3}.
2588    
2589     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2590     singly or repeated) now correctly test multibyte characters. However,
2591     PCRE doesn't recognize any characters with values greater than 255 as
2592     digits, spaces, or word characters. Such characters always match \D, \S,
2593     and \W, and never match \d, \s, or \w.
2594    
2595     (v) Classes may now contain characters and character ranges with values
2596     greater than 255. For example: [ab\x{100}-\x{400}].
2597    
2598     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2599     PCRE in UTF-8 mode.
2600    
2601     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2602     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2603     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2604     value.)
2605    
2606     53. The single man page has become too large. I have therefore split it up into
2607     a number of separate man pages. These also give rise to individual HTML pages;
2608     these are now put in a separate directory, and there is an index.html page that
2609     lists them all. Some hyperlinking between the pages has been installed.
2610    
2611     54. Added convenience functions for handling named capturing parentheses.
2612    
2613     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2614     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2615     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2616     are faulted.
2617    
2618     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2619     calling configure. These values are used when compiling the dftables.c program
2620     which is run to generate the source of the default character tables. They
2621     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2622     you will need to set these values.
2623    
2624     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2625    
2626    
2627     Version 3.9 02-Jan-02
2628 nigel 61 ---------------------
2629    
2630     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2631    
2632     2. If --disable-static was given, the building process failed when trying to
2633     build pcretest and pcregrep. (For some reason it was using libtool to compile
2634     them, which is not right, as they aren't part of the library.)
2635    
2636    
2637 nigel 59 Version 3.8 18-Dec-01
2638     ---------------------
2639    
2640     1. The experimental UTF-8 code was completely screwed up. It was packing the
2641     bytes in the wrong order. How dumb can you get?
2642    
2643    
2644 nigel 57 Version 3.7 29-Oct-01
2645     ---------------------
2646    
2647     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2648     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2649     this didn't happen under Solaris 8, where I normally test things.
2650    
2651 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2652     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2653     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2654     this fix an hour or so after the initial 3.7 release.)
2655 nigel 57
2656 nigel 59
2657 nigel 55 Version 3.6 23-Oct-01
2658     ---------------------
2659    
2660     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2661     offsets passed as NULL with zero offset count.
2662    
2663     2. The config.guess and config.sub files had not been updated when I moved to
2664     the latest autoconf.
2665    
2666    
2667 nigel 53 Version 3.5 15-Aug-01
2668     ---------------------
2669 nigel 5
2670 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2671     had been forgotten.
2672    
2673     2. By using declared but undefined structures, we can avoid using "void"
2674     definitions in pcre.h while keeping the internal definitions of the structures
2675     private.
2676    
2677     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2678     user point of view, this means that both static and shared libraries are built
2679     by default, but this can be individually controlled. More of the work of
2680     handling this static/shared cases is now inside libtool instead of PCRE's make
2681     file.
2682    
2683     4. The pcretest utility is now installed along with pcregrep because it is
2684     useful for users (to test regexs) and by doing this, it automatically gets
2685     relinked by libtool. The documentation has been turned into a man page, so
2686     there are now .1, .txt, and .html versions in /doc.
2687    
2688     5. Upgrades to pcregrep:
2689     (i) Added long-form option names like gnu grep.
2690     (ii) Added --help to list all options with an explanatory phrase.
2691     (iii) Added -r, --recursive to recurse into sub-directories.
2692     (iv) Added -f, --file to read patterns from a file.
2693    
2694     6. pcre_exec() was referring to its "code" argument before testing that
2695     argument for NULL (and giving an error if it was NULL).
2696    
2697     7. Upgraded Makefile.in to allow for compiling in a different directory from
2698     the source directory.
2699    
2700     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2701     options bits, the pointer it was passed was to an int instead of to an unsigned
2702     long int. This mattered only on 64-bit systems.
2703    
2704     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2705     generated) instead of pcre.in, which it its source. Also made the same change
2706     in several of the .c files.
2707    
2708     10. A new release of gcc defines printf() as a macro, which broke pcretest
2709     because it had an ifdef in the middle of a string argument for printf(). Fixed
2710     by using separate calls to printf().
2711    
2712     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2713     script, to force use of CR or LF instead of \n in the source. On non-Unix
2714     systems, the value can be set in config.h.
2715    
2716     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2717     absolute limit. Changed the text of the error message to make this clear, and
2718     likewise updated the man page.
2719    
2720     13. The limit of 99 on the number of capturing subpatterns has been removed.
2721     The new limit is 65535, which I hope will not be a "real" limit.
2722    
2723    
2724 nigel 51 Version 3.4 22-Aug-00
2725     ---------------------
2726    
2727     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2728    
2729     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2730    
2731    
2732 nigel 49 Version 3.3 01-Aug-00
2733     ---------------------
2734    
2735     1. If an octal character was given, but the value was greater than \377, it
2736     was not getting masked to the least significant bits, as documented. This could
2737     lead to crashes in some systems.
2738    
2739     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2740     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2741    
2742     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2743     These just pass their arguments on to (pcre_free)(), but they are provided
2744     because some uses of PCRE bind it to non-C systems that can call its functions,
2745     but cannot call free() or pcre_free() directly.
2746    
2747     4. Add "make test" as a synonym for "make check". Corrected some comments in
2748     the Makefile.
2749    
2750     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2751     Makefile.
2752    
2753     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2754     command called pgrep for grepping around the active processes.
2755    
2756     7. Added the beginnings of support for UTF-8 character strings.
2757    
2758     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2759     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2760     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2761     out for the ar command.)
2762    
2763    
2764 nigel 47 Version 3.2 12-May-00
2765     ---------------------
2766    
2767     This is purely a bug fixing release.
2768    
2769     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2770     of ZA. This was just one example of several cases that could provoke this bug,
2771     which was introduced by change 9 of version 2.00. The code for breaking
2772     infinite loops after an iteration that matches an empty string was't working
2773     correctly.
2774    
2775     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2776     when matched against abbab (for example). After matching an empty string, it
2777     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2778     caused it to match further down the string than it should.
2779    
2780     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2781     was there because it doesn't seem to be needed, and it causes trouble on some
2782     systems, as it is not a Standard C header. It has been removed.
2783    
2784     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2785     were reported on the Macintosh. The changes were from
2786    
2787     while ((c = *(++ptr)) != 0 && c != '\n');
2788     to
2789     while ((c = *(++ptr)) != 0 && c != '\n') ;
2790    
2791     Totally extraordinary, but if that's what it takes...
2792    
2793     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2794     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2795     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2796     assumes the way PCRE uses memmove() (always moving upwards).
2797    
2798     6. PCRE is being used in one environment where strchr() is not available. There
2799     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2800     faster code anyway.
2801    
2802    
2803 nigel 45 Version 3.1 09-Feb-00
2804     ---------------------
2805    
2806     The only change in this release is the fixing of some bugs in Makefile.in for
2807     the "install" target:
2808    
2809     (1) It was failing to install pcreposix.h.
2810    
2811     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2812    
2813    
2814 nigel 43 Version 3.0 01-Feb-00
2815     ---------------------
2816 nigel 41
2817     1. Add support for the /+ modifier to perltest (to output $` like it does in
2818     pcretest).
2819    
2820     2. Add support for the /g modifier to perltest.
2821    
2822     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2823     matches null strings.
2824    
2825     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2826     pattern. Perl treats empty patterns specially - it reuses the most recent
2827     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2828     effect.
2829    
2830     5. The POSIX interface was broken in that it was just handing over the POSIX
2831     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2832     required a bigger vector, with some working space on the end. This means that
2833     the POSIX wrapper now has to get and free some memory, and copy the results.
2834    
2835 nigel 43 6. Added some simple autoconf support, placing the test data and the
2836     documentation in separate directories, re-organizing some of the
2837     information files, and making it build pcre-config (a GNU standard). Also added
2838     libtool support for building PCRE as a shared library, which is now the
2839     default.
2840 nigel 41
2841 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2842     09 are not valid octal constants. Single digits will be used for minor values
2843     less than 10.
2844    
2845     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2846     existing programs that set these in the POSIX interface can use PCRE without
2847     modification.
2848    
2849     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2850     return all that pcre_info() returns, plus additional data. The pcre_info()
2851     function is retained for compatibility, but is considered to be obsolete.
2852    
2853     10. Added experimental recursion feature (?R) to handle one common case that
2854     Perl 5.6 will be able to do with (?p{...}).
2855    
2856     11. Added support for POSIX character classes like [:alpha:], which Perl is
2857     adopting.
2858    
2859    
2860 nigel 39 Version 2.08 31-Aug-99
2861     ----------------------
2862    
2863     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2864     trying to match at the startoffset position, but instead was moving forward to
2865     the next newline as if a previous match had failed.
2866    
2867     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2868     and could get into a loop if a null string was matched other than at the start
2869     of the subject.
2870    
2871     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2872     be distinguished at compile time, and for completeness also added PCRE_DATE.
2873    
2874     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2875     in GnuWin32 environments.
2876    
2877    
2878 nigel 37 Version 2.07 29-Jul-99
2879     ----------------------
2880    
2881     1. The documentation is now supplied in plain text form and HTML as well as in
2882     the form of man page sources.
2883    
2884     2. C++ compilers don't like assigning (void *) values to other pointer types.
2885     In particular this affects malloc(). Although there is no problem in Standard
2886     C, I've put in casts to keep C++ compilers happy.
2887    
2888     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2889     should be (const char *).
2890    
2891     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2892     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2893     However, I haven't made this a standard facility. The documentation doesn't
2894     mention it, and the Makefile doesn't support it.
2895    
2896     5. The Makefile now contains an "install" target, with editable destinations at
2897     the top of the file. The pcretest program is not installed.
2898    
2899     6. pgrep -V now gives the PCRE version number and date.
2900    
2901     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2902     causing the entire string to be ignored, instead of just the last character.
2903    
2904     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2905     non-matching string, it can take a very, very long time, even for strings of
2906     quite modest length, because of the nested recursion. PCRE now does better in
2907     some of these cases. It does this by remembering the last required literal
2908     character in the pattern, and pre-searching the subject to ensure it is present
2909     before running the real match. In other words, it applies a heuristic to detect
2910     some types of certain failure quickly, and in the above example, if presented
2911     with a string that has no trailing " it gives "no match" very quickly.
2912    
2913     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2914     other alternatives are tried instead.
2915    
2916    
2917 nigel 35 Version 2.06 09-Jun-99
2918     ----------------------
2919    
2920     1. Change pcretest's output for amount of store used to show just the code
2921     space, because the remainder (the data block) varies in size between 32-bit and
2922     64-bit systems.
2923    
2924     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2925     start matching at. This allows lookbehinds to work when searching for multiple
2926     occurrences in a string.
2927    
2928     3. Added additional options to pcretest for testing multiple occurrences:
2929    
2930     /+ outputs the rest of the string that follows a match
2931     /g loops for multiple occurrences, using the new startoffset argument
2932     /G loops for multiple occurrences by passing an incremented pointer
2933    
2934     4. PCRE wasn't doing the "first character" optimization for patterns starting
2935     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2936     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2937     the letter 'x'. On long subject strings, this gives a significant speed-up.
2938    
2939    
2940 nigel 33 Version 2.05 21-Apr-99
2941     ----------------------
2942    
2943     1. Changed the type of magic_number from int to long int so that it works
2944     properly on 16-bit systems.
2945    
2946     2. Fixed a bug which caused patterns starting with .* not to work correctly
2947     when the subject string contained newline characters. PCRE was assuming
2948     anchoring for such patterns in all cases, which is not correct because .* will
2949     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2950     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2951     must be retried after every newline in the subject.
2952    
2953    
2954 nigel 31 Version 2.04 18-Feb-99
2955     ----------------------
2956    
2957     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2958     computation of the store needed to hold the pattern was incorrect (too large).
2959     If such patterns were nested a few deep, this could multiply and become a real
2960     problem.
2961    
2962     2. Added /M option to pcretest to show the memory requirement of a specific
2963     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2964    
2965     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2966     compiled in such a way that the backtracking after subsequent failure was
2967     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2968     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2969    
2970    
2971 nigel 29 Version 2.03 02-Feb-99
2972     ----------------------
2973    
2974     1. Fixed typo and small mistake in man page.
2975    
2976 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2977     LICENCE file containing the conditions.
2978 nigel 29
2979     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2980     Perl, that is the internal \ allows the delimiter to be included in the
2981     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2982     the final delimiter, add \ to the end of the pattern (to test the error).
2983    
2984     4. Added the convenience functions for extracting substrings after a successful
2985     match. Updated pcretest to make it able to test these functions.
2986    
2987    
2988 nigel 27 Version 2.02 14-Jan-99
2989     ----------------------
2990    
2991     1. Initialized the working variables associated with each extraction so that
2992     their saving and restoring doesn't refer to uninitialized store.
2993    
2994     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2995     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2996     fix the problem.
2997    
2998     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2999     calls, and wasn't printing the correct value for compiling calls. Increased the
3000     default value of LOOPREPEAT, and the number of significant figures in the
3001     times.
3002    
3003     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3004    
3005     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3006     a building problem on Windows NT with a FAT file system.
3007    
3008    
3009 nigel 25 Version 2.01 21-Oct-98
3010     ----------------------
3011    
3012     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3013     to character tables built by pcre_maketables() in the current locale. If NULL
3014     is passed, the default tables are used.
3015    
3016    
3017 nigel 23 Version 2.00 24-Sep-98
3018 nigel 21 ----------------------
3019    
3020 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3021     it any more.
3022    
3023     2. Allow quantification of (?>) groups, and make it work correctly.
3024    
3025     3. The first character computation wasn't working for (?>) groups.
3026    
3027     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3028     end of the subject) and add 5.005's \z, which really does match only at the
3029     very end of the subject.
3030    
3031     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3032    
3033     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3034     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3035     localized options. All options to pcre_study() were also removed.
3036    
3037     7. Add other new features from 5.005:
3038    
3039     $(?<= positive lookbehind
3040     $(?<! negative lookbehind
3041     (?imsx-imsx) added the unsetting capability
3042     such a setting is global if at outer level; local otherwise
3043     (?imsx-imsx:) non-capturing groups with option setting
3044     (?(cond)re|re) conditional pattern matching
3045    
3046     A backreference to itself in a repeated group matches the previous
3047     captured string.
3048    
3049     8. General tidying up of studying (both automatic and via "study")
3050     consequential on the addition of new assertions.
3051    
3052     9. As in 5.005, unlimited repeated groups that could match an empty substring
3053     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3054     runtime if any iteration does actually match an empty substring.
3055    
3056     10. Include the RunTest script in the distribution.
3057    
3058     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3059     discrepancies, some of which were old and were also with respect to 5.004. They
3060     have now been fixed.
3061    
3062    
3063     Version 1.09 28-Apr-98
3064     ----------------------
3065    
3066 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3067     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3068     program crashes, or just wrong answers. This did not apply to negated classes
3069     containing more than one character, or to minima other than one.
3070    
3071    
3072 nigel 19 Version 1.08 27-Mar-98
3073     ----------------------
3074    
3075     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3076    
3077     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3078     latter must appear before anything that relies on it in the pattern.
3079    
3080    
3081 nigel 17 Version 1.07 16-Feb-98
3082     ----------------------
3083    
3084     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3085     repeat of a potentially empty string).
3086    
3087    
3088 nigel 15 Version 1.06 23-Jan-98
3089     ----------------------
3090    
3091     1. Added Markus Oberhumer's little patches for C++.
3092    
3093     2. Literal strings longer than 255 characters were broken.
3094    
3095    
3096 nigel 13 Version 1.05 23-Dec-97
3097     ----------------------
3098    
3099     1. Negated character classes containing more than one character were failing if
3100     PCRE_CASELESS was set at run time.
3101    
3102    
3103 nigel 11 Version 1.04 19-Dec-97
3104     ----------------------
3105    
3106     1. Corrected the man page, where some "const" qualifiers had been omitted.
3107    
3108     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3109     input syntax.
3110    
3111     3. Fixed memory leak which occurred when a regex with back references was
3112     matched with an offsets vector that wasn't big enough. The temporary memory
3113     that is used in this case wasn't being freed if the match failed.
3114    
3115     4. Tidied pcretest to ensure it frees memory that it gets.
3116    
3117     5. Temporary memory was being obtained in the case where the passed offsets
3118     vector was exactly big enough.
3119    
3120     6. Corrected definition of offsetof() from change 5 below.
3121    
3122     7. I had screwed up change 6 below and broken the rules for the use of
3123     setjmp(). Now fixed.
3124    
3125    
3126 nigel 9 Version 1.03 18-Dec-97
3127     ----------------------
3128    
3129     1. A erroneous regex with a missing opening parenthesis was correctly
3130     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3131     on some systems.
3132    
3133     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3134     it was reported that one broken compiler failed on the former because "code" is
3135     also an independent variable.
3136    
3137     3. The erroneous regex a[]b caused an array overrun reference.
3138    
3139     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3140     fail on data ending with that character. (It was going on too far, and checking
3141     the next character, typically a binary zero.) This was specific to the
3142     optimized code for single-character negative classes.
3143    
3144     5. Added a contributed patch from the TIN world which does the following:
3145    
3146     + Add an undef for memmove, in case the the system defines a macro for it.
3147    
3148     + Add a definition of offsetof(), in case there isn't one. (I don't know
3149     the reason behind this - offsetof() is part of the ANSI standard - but
3150     it does no harm).
3151    
3152     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3153     most of the places where whitespace preceded '#'. I have given up and
3154     allowed the remaining 2 cases to be at the margin.
3155    
3156     + Rename some variables in pcre to eliminate shadowing. This seems very
3157     pedantic, but does no harm, of course.
3158    
3159     6. Moved the call to setjmp() into its own function, to get rid of warnings
3160     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3161    
3162     7. Constructs such as \d{8,} were compiling into the equivalent of
3163 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3164 nigel 9 outcome, but in this particular case used more store than had been allocated,
3165     which caused the bug to be discovered because it threw up an internal error.
3166    
3167     8. The debugging code in both pcre and pcretest for outputting the compiled
3168     form of a regex was going wrong in the case of back references followed by
3169     curly-bracketed repeats.
3170    
3171    
3172 nigel 7 Version 1.02 12-Dec-97
3173     ----------------------
3174    
3175     1. Typos in pcre.3 and comments in the source fixed.
3176    
3177     2. Applied a contributed patch to get rid of places where it used to remove
3178     'const' from variables, and fixed some signed/unsigned and uninitialized
3179     variable warnings.
3180    
3181     3. Added the "runtest" target to Makefile.
3182    
3183     4. Set default compiler flag to -O2 rather than just -O.
3184    
3185    
3186 nigel 5 Version 1.01 19-Nov-97
3187     ----------------------
3188    
3189     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3190     like /([ab]*)*/, that is, for classes with more than one character in them.
3191    
3192     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3193     as /((?>a*))*/ (a PCRE_EXTRA facility).
3194    
3195    
3196     Version 1.00 18-Nov-97
3197     ----------------------
3198    
3199     1. Added compile-time macros to support systems such as SunOS4 which don't have
3200     memmove() or strerror() but have other things that can be used instead.
3201    
3202     2. Arranged that "make clean" removes the executables.
3203    
3204    
3205 nigel 3 Version 0.99 27-Oct-97
3206     ----------------------
3207    
3208     1. Fixed bug in code for optimizing classes with only one character. It was
3209     initializing a 32-byte map regardless, which could cause it to run off the end
3210     of the memory it had got.
3211    
3212     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3213    
3214    
3215     Version 0.98 22-Oct-97
3216     ----------------------
3217    
3218     1. Fixed bug in code for handling temporary memory usage when there are more
3219     back references than supplied space in the ovector. This could cause segfaults.
3220    
3221    
3222     Version 0.97 21-Oct-97
3223     ----------------------
3224    
3225     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3226    
3227     2. Optimized negated single characters not to use a bit map.
3228    
3229     3. Brought error texts together as macro definitions; clarified some of them;
3230     fixed one that was wrong - it said "range out of order" when it meant "invalid
3231     escape sequence".
3232    
3233     4. Changed some char * arguments to const char *.
3234    
3235     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3236    
3237     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3238     pcretest.
3239    
3240    
3241     Version 0.96 16-Oct-97
3242     ----------------------
3243    
3244     1. Added a simple "pgrep" utility to the distribution.
3245    
3246     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3247     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3248     where "ddd" means "one or more decimal digits".
3249    
3250     3. Fixed serious bug. If a pattern had a back reference, but the call to
3251     pcre_exec() didn't supply a large enough ovector to record the related
3252     identifying subpattern, the match always failed. PCRE now remembers the number
3253     of the largest back reference, and gets some temporary memory in which to save
3254     the offsets during matching if necessary, in order to ensure that
3255     backreferences always work.
3256    
3257     4. Increased the compatibility with Perl in a number of ways:
3258    
3259     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3260     to request this handling. The option can be set at compile or exec time.
3261    
3262     (b) $ matches before a terminating newline by default; an option
3263     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3264     mode). The option can be set at compile or exec time.
3265    
3266     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3267     the same as Perl's. If the decimal number it represents is less than 10
3268     or there aren't that many previous left capturing parentheses, an octal
3269     escape is read. Inside a character class, it's always an octal escape,
3270     even if it is a single digit.
3271    
3272     (d) An escaped but undefined alphabetic character is taken as a literal,
3273     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3274     escapes.
3275    
3276     (e) {0} is now permitted. (The previous item is removed from the compiled
3277     pattern).
3278    
3279     5. Changed all the names of code files so that the basic parts are no longer
3280     than 10 characters, and abolished the teeny "globals.c" file.
3281    
3282     6. Changed the handling of character classes; they are now done with a 32-byte
3283     bit map always.
3284    
3285     7. Added the -d and /D options to pcretest to make it possible to look at the
3286     internals of compilation without having to recompile pcre.
3287    
3288    
3289     Version 0.95 23-Sep-97
3290     ----------------------
3291    
3292     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3293     \x20 at the start of a run of normal characters. These were being treated as
3294     real characters, instead of the source characters being re-checked.
3295    
3296    
3297     Version 0.94 18-Sep-97
3298     ----------------------
3299    
3300     1. The functions are now thread-safe, with the caveat that the global variables
3301     containing pointers to malloc() and free() or alternative functions are the
3302     same for all threads.
3303    
3304     2. Get pcre_study() to generate a bitmap of initial characters for non-
3305     anchored patterns when this is possible, and use it if passed to pcre_exec().
3306    
3307    
3308     Version 0.93 15-Sep-97
3309     ----------------------
3310    
3311     1. /(b)|(:+)/ was computing an incorrect first character.
3312    
3313     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3314     but not actually doing anything yet.
3315    
3316     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3317     as Perl does (e.g. [-az] or [az-]).
3318    
3319     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3320     all possible positions.
3321    
3322     5. Split up into different modules to avoid including unneeded functions in a
3323     compiled binary. However, compile and exec are still in one module. The "study"
3324     function is split off.
3325    
3326     6. The character tables are now in a separate module whose source is generated
3327     by an auxiliary program - but can then be edited by hand if required. There are
3328     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3329     toupper() in the code.
3330    
3331     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3332     make them global. Abolish the function for setting them, as the caller can now
3333     set them directly.
3334    
3335    
3336     Version 0.92 11-Sep-97
3337     ----------------------
3338    
3339     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3340     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3341    
3342     2. Caseless matching was not working in character classes if the characters in
3343     the pattern were in upper case.
3344    
3345     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3346    
3347     4. Make PCRE_ANCHORED public and accept as a compile option.
3348    
3349     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3350     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3351     pass them.
3352    
3353     6. Give an error if bad option bits passed at compile or run time.
3354    
3355     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3356     pcretest to cause it to pass that flag.
3357    
3358     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3359     options, and the first character, if set.
3360    
3361     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3362    
3363    
3364     Version 0.91 10-Sep-97
3365     ----------------------
3366    
3367     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3368     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3369    
3370     2. PCRE was looping on encountering an indefinitely repeated back reference to
3371     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3372     Perl does - treats the match as successful.
3373    
3374     ****

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