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Revision 393 - (hide annotations) (download)
Tue Mar 17 21:47:54 2009 UTC (5 years, 4 months ago) by ph10
File size: 162918 byte(s)
Force SUPPORT_UTF8 if SUPPORT_UCP is set (for non-"configure" users).

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 376 Version 7.9 xx-xxx-09
5     ---------------------
6    
7 ph10 392 1. When building with support for bzlib/zlib (pcregrep) and/or readline
8 ph10 376 (pcretest), all targets were linked against these libraries. This included
9     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
10     libraries. This caused unwanted dependencies to be created. This problem
11 ph10 392 has been fixed, and now only pcregrep is linked with bzlib/zlib and only
12 ph10 376 pcretest is linked with readline.
13 ph10 392
14 ph10 376 2. The "typedef int BOOL" in pcre_internal.h that was included inside the
15     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
16     moved outside it again, because FALSE and TRUE are already defined in AIX,
17     but BOOL is not.
18 ph10 392
19     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
20 ph10 376 PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.
21 ph10 392
22 ph10 376 4. The pcregrep documentation said spaces were inserted as well as colons (or
23     hyphens) following file names and line numbers when outputting matching
24 ph10 392 lines. This is not true; no spaces are inserted. I have also clarified the
25 ph10 376 wording for the --colour (or --color) option.
26 ph10 392
27 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
28     was not coloured; this is different to GNU grep, so I have changed it to be
29     the same.
30 ph10 392
31 ph10 378 6. When --colo(u)r was used in pcregrep, only the first matching substring in
32 ph10 392 each matching line was coloured. Now it goes on to look for further matches
33     of any of the test patterns, which is the same behaviour as GNU grep.
34    
35     7. A pattern that could match an empty string could cause pcregrep to loop; it
36     doesn't make sense to accept an empty string match in pcregrep, so I have
37 ph10 379 locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38     seems to be how GNU grep behaves.
39 ph10 392
40 ph10 380 8. The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
41 ph10 392 start or after a newline", because the conditional assertion was not being
42     correctly handled. The rule now is that both the assertion and what follows
43     in the first alternative must satisfy the test.
44    
45     9. If auto-callout was enabled in a pattern with a conditional group, PCRE
46 ph10 381 could crash during matching.
47 ph10 392
48     10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
49     used for matching.
50    
51     11. Unicode property support in character classes was not working for
52 ph10 385 characters (bytes) greater than 127 when not in UTF-8 mode.
53 ph10 388
54 ph10 392 12. Added the -M command line option to pcretest.
55    
56 ph10 388 14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
57 ph10 389
58     15. Added the PCRE_NO_START_OPTIMIZE match-time option.
59 ph10 390
60 ph10 392 16. Added comments and documentation about mis-use of no_arg in the C++
61 ph10 390 wrapper.
62 ph10 392
63 ph10 391 17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
64 ph10 392 from Martin Jerabek that uses macro names for all relevant character and
65 ph10 391 string constants.
66 ph10 393
67     18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
68     SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
69     SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
70     these, but not everybody uses configure.
71 ph10 376
72 ph10 392
73 ph10 374 Version 7.8 05-Sep-08
74 ph10 349 ---------------------
75    
76     1. Replaced UCP searching code with optimized version as implemented for Ad
77     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
78 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
79     to 5 times on some simple patterns that I tested. Permission was given to
80     distribute the MultiStage2.py script that generates the tables (it's not in
81     the tarball, but is in the Subversion repository).
82 ph10 349
83 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
84     scripts.
85 ph10 358
86 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
87     a group with a zero qualifier. The result of the study could be incorrect,
88 ph10 358 or the function might crash, depending on the pattern.
89    
90     4. Caseless matching was not working for non-ASCII characters in back
91 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
92 ph10 358 It now works when Unicode Property Support is available.
93    
94 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
95     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
96     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
97 ph10 358 truncation.
98 ph10 349
99 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
100    
101 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
102     pointers, in case they are 64-bit values.
103 ph10 371
104     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
105     test 2 if it fails.
106    
107 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
108 ph10 371 and a #define of that name to empty if it is not externally set. This is to
109     allow users of MSVC to set it if necessary.
110    
111     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
112 ph10 359 the convenience functions in the pcre_get.c source file.
113 ph10 371
114 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
115     could cause overwriting and/or a crash. This command provoked a crash in
116 ph10 371 some environments:
117    
118     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
119    
120 ph10 360 This potential security problem was recorded as CVE-2008-2371.
121 ph10 371
122 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
123     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
124 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
125 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
126     pcretest so that it places the subject at the end of its malloc-ed buffer.
127 ph10 371
128 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
129 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
130    
131 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
132 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
133     first line. This applied both to normal and DFA matching.
134    
135 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
136 ph10 371 /^[^d]*?$/8 failed to match "abc".
137 ph10 351
138 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
139    
140     17. Make it more clear in the documentation that values returned from
141 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
142 ph10 357
143 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
144 ph10 368
145 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
146     supplied by Stefan Weber. I made a further small update for 7.8 because
147 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
148     replaced by pcre_ucd.c.
149 ph10 371
150 ph10 373
151 ph10 347 Version 7.7 07-May-08
152 ph10 321 ---------------------
153    
154     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
155 ph10 345 a string to a long long, pretend we don't even have a long long." This is
156 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
157 ph10 345
158 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
159     pre-7.6 versions, which defined a global no_arg variable instead of putting
160 ph10 332 it in the RE class. (See also #8 below.)
161 ph10 345
162     3. Remove a line of dead code, identified by coverity and reported by Nuno
163     Lopes.
164    
165 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
166 ph10 321
167 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
168 ph10 345 of files, instead of just to the final components.
169    
170 ph10 324 (2) If there was more than one level of directory, the subdirectories were
171     skipped unless they satisfied the include/exclude conditions. This is
172     inconsistent with GNU grep (and could even be seen as contrary to the
173     pcregrep specification - which I improved to make it absolutely clear).
174     The action now is always to scan all levels of directory, and just
175     apply the include/exclude patterns to regular files.
176 ph10 345
177 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
178 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
179    
180 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
181 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
182 ph10 326 doesn't support NULs in patterns.
183 ph10 345
184     7. Added some missing "const"s to declarations of static tables in
185     pcre_compile.c and pcre_dfa_exec.c.
186    
187 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
188 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
189 ph10 345 first patch. And a third patch - this was a messy problem.)
190 ph10 321
191 ph10 345 9. Applied Craig's patch to remove the use of push_back().
192    
193 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
194     matching function regexec().
195 ph10 345
196     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
197     which, however, unlike Perl's \g{...}, are subroutine calls, not back
198 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
199     Oniguruma does).
200 ph10 345
201     12. Previously, a group with a zero repeat such as (...){0} was completely
202 ph10 335 omitted from the compiled regex. However, this means that if the group
203     was called as a subroutine from elsewhere in the pattern, things went wrong
204 ph10 345 (an internal error was given). Such groups are now left in the compiled
205     pattern, with a new opcode that causes them to be skipped at execution
206 ph10 335 time.
207 ph10 345
208 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
209     to the way PCRE behaves:
210 ph10 345
211 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
212 ph10 345
213     (b) A back reference to an unmatched subpattern matches an empty string
214 ph10 336 (Perl fails the current match path).
215 ph10 345
216 ph10 341 (c) A data ] in a character class must be notated as \] because if the
217 ph10 345 first data character in a class is ], it defines an empty class. (In
218 ph10 341 Perl it is not possible to have an empty class.) The empty class []
219     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
220     The negative empty class [^] matches any one character, independently
221     of the DOTALL setting.
222 ph10 345
223     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
224 ph10 340 non-existent subpattern following a character class starting with ']' and
225     containing () gave an internal compiling error instead of "reference to
226     non-existent subpattern". Fortunately, when the pattern did exist, the
227 ph10 345 compiled code was correct. (When scanning forwards to check for the
228 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
229 ph10 345 the class, so got the count wrong. When actually compiling, the reference
230 ph10 340 was subsequently set up correctly.)
231 ph10 345
232 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
233 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
234     other assertions are supported. I have made pcre_dfa_exec() support
235     (*FAIL).
236    
237 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
238 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
239     cannot be changed at match time, I realized I could make a small
240     improvement to matching performance by compiling OP_ALLANY instead of
241     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
242     on the OP_ANY path.
243    
244     17. Compiling pcretest on Windows with readline support failed without the
245 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
246 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
247    
248 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
249 ph10 345 ncurses library to be included for pcretest when ReadLine support is
250     requested, but also to allow for it to be overridden. This patch came from
251     Daniel Bergström.
252 ph10 347
253 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
254 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
255     any errors with the current Unicode tables. Thanks to Peter Kankowski for
256     spotting this.
257 ph10 324
258 ph10 332
259 ph10 319 Version 7.6 28-Jan-08
260 ph10 300 ---------------------
261    
262 ph10 302 1. A character class containing a very large number of characters with
263     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
264     overflow.
265 ph10 309
266     2. Patch to cut out the "long long" test in pcrecpp_unittest when
267     HAVE_LONG_LONG is not defined.
268    
269 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
270 ph10 304 bring them up to date and include new features. This patch includes:
271 ph10 309
272 ph10 304 - Fixed PH's badly added libz and libbz2 support.
273     - Fixed a problem with static linking.
274 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
275 ph10 304 - Fixed dftables problem and added an option.
276     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
277     HAVE_LONG_LONG.
278     - Added readline support for pcretest.
279 ph10 309 - Added an listing of the option settings after cmake has run.
280    
281 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
282     "pcre.dll" under mingw when using Configure/Make. I added stuff to
283     Makefile.am that cause it to include this special target, without
284     affecting anything else. Note that the same mingw target plus all
285     the other distribution libraries and programs are now supported
286     when configuring with CMake (see 6 below) instead of with
287     Configure/Make.
288 ph10 309
289 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
290     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
291 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
292     solves the problem, but it does no harm.
293 ph10 313
294 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
295 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
296 ph10 314 with CMake, and also correct the comment about stack recursion.
297 ph10 313
298 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
299 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
300     of a program that users should build themselves after PCRE is installed, so
301     building it automatically is not really right. What is more, it gave
302 ph10 312 trouble in some build environments.
303 ph10 300
304 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
305 ph10 308
306 ph10 319
307 ph10 298 Version 7.5 10-Jan-08
308 ph10 263 ---------------------
309    
310     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
311     values in parens when parsing an RE using the C++ wrapper."
312 ph10 286
313 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
314     Characters greater than 255 were excluded from the class instead of being
315     included.
316 ph10 286
317     3. The same bug as (2) above applied to negated POSIX classes such as
318 ph10 265 [:^space:].
319 ph10 286
320 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
321     defined or documented. It seems to have been a typo for PCRE_STATIC, so
322 ph10 286 I have changed it.
323    
324 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
325 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
326     first named subpattern whose name started with "a" (in other words, the
327 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
328     expected" is now given for (?&) (a zero-length name), and this patch also
329     makes it give the same error for \k'' (previously it complained that that
330     was a reference to a non-existent subpattern).
331 ph10 286
332 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
333 ph10 286 this is right because (?- can be followed by option settings as well as by
334 ph10 269 digits. I have, however, made the messages clearer.
335 ph10 286
336 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
337     than the number used in the conditional) now cause a compile-time error.
338     This is actually not compatible with Perl, which accepts such patterns, but
339     treats the conditional as always being FALSE (as PCRE used to), but it
340     seems to me that giving a diagnostic is better.
341 ph10 286
342 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
343 ph10 275 and messages.
344 ph10 286
345     9. Fix two occurrences of "backslash" in comments that should have been
346     "backspace".
347    
348     10. Remove two redundant lines of code that can never be obeyed (their function
349     was moved elsewhere).
350    
351     11. The program that makes PCRE's Unicode character property table had a bug
352     which caused it to generate incorrect table entries for sequences of
353 ph10 277 characters that have the same character type, but are in different scripts.
354 ph10 286 It amalgamated them into a single range, with the script of the first of
355 ph10 277 them. In other words, some characters were in the wrong script. There were
356     thirteen such cases, affecting characters in the following ranges:
357 ph10 286
358 ph10 277 U+002b0 - U+002c1
359     U+0060c - U+0060d
360 ph10 286 U+0061e - U+00612
361 ph10 277 U+0064b - U+0065e
362     U+0074d - U+0076d
363     U+01800 - U+01805
364     U+01d00 - U+01d77
365     U+01d9b - U+01dbf
366     U+0200b - U+0200f
367     U+030fc - U+030fe
368     U+03260 - U+0327f
369     U+0fb46 - U+0fbb1
370     U+10450 - U+1049d
371 ph10 286
372 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
373     compatible with GNU grep in that, if there was more than one match in a
374     line, it showed only the first of them. It now behaves in the same way as
375     GNU grep.
376 ph10 286
377     13. If the -o and -v options were combined for pcregrep, it printed a blank
378     line for every non-matching line. GNU grep prints nothing, and pcregrep now
379     does the same. The return code can be used to tell if there were any
380     non-matching lines.
381    
382 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
383    
384     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
385 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
386 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
387     and both kinds of lookbehind were skipped).
388    
389 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
390 ph10 284 inclusion of <windows.h> to before rather than after the definition of
391     INVALID_FILE_ATTRIBUTES (patch from David Byron).
392 ph10 263
393 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
394 ph10 286 character property caused pcre_compile() to compile bad code, which led at
395     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
396     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
397     caused the error; without that there was no problem.
398 ph10 263
399 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
400 ph10 286
401 ph10 289 19. Added --enable-pcretest-libreadline.
402 ph10 286
403 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
404 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
405 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
406     later patch that removed the other one (the right fix) and added unit tests
407     that check the return values (which was not done before).
408 ph10 292
409 ph10 291 21. Several CMake things:
410 ph10 287
411 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
412 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
413 ph10 288
414 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
415     linked with the newly-built libraries, not previously installed ones.
416 ph10 291
417 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
418 ph10 298
419     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
420     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
421     UTF-8 newline character). The key issue is that the pattern starts .*;
422     this means that the match must be either at the beginning, or after a
423     newline. The bug was in the code for advancing after a failed match and
424     checking that the new position followed a newline. It was not taking
425 ph10 294 account of UTF-8 characters correctly.
426 ph10 298
427     23. PCRE was behaving differently from Perl in the way it recognized POSIX
428     character classes. PCRE was not treating the sequence [:...:] as a
429     character class unless the ... were all letters. Perl, however, seems to
430     allow any characters between [: and :], though of course it rejects as
431     unknown any "names" that contain non-letters, because all the known class
432     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
433     for example, whereas PCRE did not - it did not recognize a POSIX character
434     class. This seemed a bit dangerous, so the code has been changed to be
435     closer to Perl. The behaviour is not identical to Perl, because PCRE will
436     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
437     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
438     Perl does, and where it didn't before.
439    
440 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
441     Windows environments %n is disabled by default.
442 ph10 292
443    
444 ph10 260 Version 7.4 21-Sep-07
445 ph10 230 ---------------------
446    
447     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
448 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
449     LF". That isn't really right - the whole point of the change was to try to
450     help when there was an actual mention of one of the two characters. So now
451     the change happens only if \r or \n (or a literal CR or LF) character is
452 ph10 230 encountered.
453 ph10 231
454     2. The 32-bit options word was also used for 6 internal flags, but the numbers
455     of both had grown to the point where there were only 3 bits left.
456     Fortunately, there was spare space in the data structure, and so I have
457     moved the internal flags into a new 16-bit field to free up more option
458 ph10 230 bits.
459 ph10 231
460     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
461     but did not set the internal JCHANGED flag - either of these is enough to
462     control the way the "get" function works - but the PCRE_INFO_JCHANGED
463     facility is supposed to tell if (?J) was ever used, so now (?J) at the
464 ph10 230 start sets both bits.
465    
466 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
467     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
468 ph10 230
469 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
470    
471     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
472 ph10 233 compatibility, even though it is no longer used.
473 ph10 243
474     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
475 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
476 ph10 259 windows.h file is present (where different names are used). [This was
477 ph10 257 reversed later after testing - see 16 below.]
478 ph10 243
479     8. Changed all #include <config.h> to #include "config.h". There were also
480 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
481 ph10 243
482 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
483 ph10 243 sequence off the lines that it output.
484    
485     10. It was pointed out to me that arrays of string pointers cause lots of
486     relocations when a shared library is dynamically loaded. A technique of
487     using a single long string with a table of offsets can drastically reduce
488     these. I have refactored PCRE in four places to do this. The result is
489 ph10 240 dramatic:
490 ph10 243
491 ph10 240 Originally: 290
492     After changing UCP table: 187
493 ph10 243 After changing error message table: 43
494 ph10 240 After changing table of "verbs" 36
495     After changing table of Posix names 22
496 ph10 243
497 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
498 ph10 247
499 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
500 ph10 247 unicode-properties was also set.
501    
502 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
503 ph10 231
504 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
505     checked only for CRLF.
506 ph10 233
507 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
508    
509 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
510 ph10 253
511 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
512 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
513     entirely. This removes changes made in 7 above.
514 ph10 256
515 ph10 261 17. The CMake files have been updated, and there is now more information about
516     building with CMake in the NON-UNIX-USE document.
517 ph10 257
518 ph10 261
519 ph10 228 Version 7.3 28-Aug-07
520 ph10 157 ---------------------
521    
522 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
523     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
524     brackets there is not right, since it causes compilers to look for an
525     installed pcre.h, not the version that is in the source that is being
526     compiled (which of course may be different). I have changed it back to:
527 ph10 197
528 ph10 189 #include "pcre.h"
529 ph10 197
530     I have a vague recollection that the change was concerned with compiling in
531     different directories, but in the new build system, that is taken care of
532     by the VPATH setting the Makefile.
533    
534 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
535     when the subject happened to end in the byte 0x85 (e.g. if the last
536     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
537     characters but of course it shouldn't be taken as a newline when it is part
538     of another character. The bug was that, for an unlimited repeat of . in
539     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
540     characters when looking for a newline.
541 ph10 197
542     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
543    
544     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
545     in debug output.
546    
547 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
548     long printing in the pcrecpp unittest when running under MinGW.
549 ph10 189
550 ph10 197 6. ESC_K was left out of the EBCDIC table.
551 ph10 189
552 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
553     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
554     limit also applies to "virtual nesting" when a pattern is recursive, and in
555     this case 1000 isn't so big. I have been able to remove this limit at the
556     expense of backing off one optimization in certain circumstances. Normally,
557     when pcre_exec() would call its internal match() function recursively and
558     immediately return the result unconditionally, it uses a "tail recursion"
559     feature to save stack. However, when a subpattern that can match an empty
560     string has an unlimited repetition quantifier, it no longer makes this
561     optimization. That gives it a stack frame in which to save the data for
562     checking that an empty string has been matched. Previously this was taken
563     from the 1000-entry workspace that had been reserved. So now there is no
564     explicit limit, but more stack is used.
565 ph10 189
566 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
567     syntax that is required for Windows, and which was going wrong for the
568     pcreposix and pcrecpp parts of the library. These were overlooked when this
569     problem was solved for the main library.
570 ph10 197
571 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
572     the size of patterns that contain repeated groups with explicit upper
573     limits. As the maximum quantifier is 65535, the maximum group length was
574     set at 30,000 so that the product of these two numbers did not overflow a
575     32-bit integer. However, it turns out that people want to use groups that
576     are longer than 30,000 bytes (though not repeat them that many times).
577     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
578     made it possible to implement the integer overflow checks in a much more
579     dynamic way, which I have now done. The artificial limitation on group
580     length has been removed - we now have only the limit on the total length of
581     the compiled pattern, which depends on the LINK_SIZE setting.
582 ph10 208
583     10. Fixed a bug in the documentation for get/copy named substring when
584     duplicate names are permitted. If none of the named substrings are set, the
585     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
586     empty string.
587    
588     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
589     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
590     because the ] is interpreted as the first data character and the
591     terminating ] is not found. PCRE has been made compatible with Perl in this
592     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
593     cause memory overwriting.
594    
595 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
596     string has been matched (to stop an infinite loop). It was not recognizing
597 ph10 208 a conditional subpattern that could match an empty string if that
598 ph10 206 subpattern was within another subpattern. For example, it looped when
599 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
600 ph10 206 condition was not nested. This bug has been fixed.
601 ph10 208
602 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
603     past the start of the subject in the presence of bytes with the top bit
604     set, for example "\x8aBCD".
605 ph10 211
606 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
607     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
608 ph10 200
609 ph10 211 14. Optimized (?!) to (*FAIL).
610 ph10 202
611 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
612     This restricts code points to be within the range 0 to 0x10FFFF, excluding
613     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
614     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
615     does: it's just the validity check that is more restrictive.
616 ph10 220
617     16. Inserted checks for integer overflows during escape sequence (backslash)
618     processing, and also fixed erroneous offset values for syntax errors during
619     backslash processing.
620    
621 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
622 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
623    
624 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
625     caused an overrun.
626 ph10 220
627     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
628     something other than just ASCII characters) inside a group that had an
629     unlimited repeat caused a loop at compile time (while checking to see
630     whether the group could match an empty string).
631    
632 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
633     [\P{Any}] did so. (Error in the code for printing property names.)
634 ph10 210
635 ph10 220 21. An orphan \E inside a character class could cause a crash.
636    
637     22. A repeated capturing bracket such as (A)? could cause a wild memory
638 ph10 218 reference during compilation.
639 ph10 220
640     23. There are several functions in pcre_compile() that scan along a compiled
641     expression for various reasons (e.g. to see if it's fixed length for look
642 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
643 ph10 220 present in the pattern. These operators have additional parameters compared
644     with \d, etc, and these were not being taken into account when moving along
645 ph10 218 the compiled data. Specifically:
646 ph10 220
647     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
648     length.
649    
650     (b) An item such as \pL+ within a repeated group could cause crashes or
651 ph10 218 loops.
652 ph10 220
653 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
654 ph10 220 "reference to non-existent subpattern" error.
655    
656 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
657    
658 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
659 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
660 ph10 211
661 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
662 ph10 218
663 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
664 ph10 223 character were causing crashes (broken optimization).
665 ph10 227
666 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
667 ph10 227 \p or \P) caused a compile-time loop.
668    
669 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
670     break. For example, the unstudied pattern [\r\n]A does not match the string
671     "\r\nA" because change 7.0/46 below moves the current point on by two
672     characters after failing to match at the start. However, the pattern \nA
673 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
674     the same is true. There doesn't seem any very clean way out of this, but
675     what I have chosen to do makes the common cases work: PCRE now takes note
676     of whether there can be an explicit match for \r or \n anywhere in the
677     pattern, and if so, 7.0/46 no longer applies. As part of this change,
678     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
679     pattern has explicit CR or LF references.
680 ph10 222
681 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
682 ph10 223
683 ph10 227
684 ph10 189 Version 7.2 19-Jun-07
685     ---------------------
686    
687 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
688     which is apparently normally available under Windows.
689 ph10 159
690     2. Re-jig the pcregrep tests with different newline settings in an attempt
691     to make them independent of the local environment's newline setting.
692 ph10 157
693 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
694 ph10 165
695 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
696     was not 2, because the output contained actual offsets. The recent new
697 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
698     usable with all link sizes.
699    
700 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
701     stack recursion. This gives a massive performance boost under BSD, but just
702 ph10 165 a small improvement under Linux. However, it saves one field in the frame
703 ph10 164 in all cases.
704 ph10 172
705 ph10 166 6. Added more features from the forthcoming Perl 5.10:
706 ph10 172
707 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
708     recursion call. It refers to the nth most recently opened parentheses.
709 ph10 172
710 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
711 ph10 172 to be opened parentheses.
712    
713     (c) Conditions that refer to capturing parentheses can be specified
714 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
715 ph10 172
716 ph10 168 (d) \K resets the start of the current match so that everything before
717 ph10 172 is not part of it.
718    
719 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
720 ph10 172
721 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
722 ph10 172 reference syntax.
723 ph10 182
724 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
725 ph10 182 alternative starts with the same number.
726 ph10 172
727 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
728    
729 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
730     PCRE_INFO_JCHANGED.
731    
732     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
733     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
734 ph10 170 for detecting groups that can match an empty string.
735 ph10 159
736 ph10 172 9. A pattern with a very large number of alternatives (more than several
737     hundred) was running out of internal workspace during the pre-compile
738     phase, where pcre_compile() figures out how much memory will be needed. A
739     bit of new cunning has reduced the workspace needed for groups with
740     alternatives. The 1000-alternative test pattern now uses 12 bytes of
741     workspace instead of running out of the 4096 that are available.
742 ph10 182
743 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
744 ph10 172
745 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
746     The report of the bug said:
747 ph10 182
748 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
749     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
750 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
751 ph10 185
752 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
753 ph10 185 it matched the wrong number of bytes.
754 ph10 172
755 ph10 179
756 ph10 155 Version 7.1 24-Apr-07
757 ph10 98 ---------------------
758    
759 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
760 ph10 122 that is more "standard", making use of automake and other Autotools. There
761 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
762     on this.
763 ph10 111
764     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
765     for recursive directory scanning broke on some systems because the files
766     are not scanned in any specific order and on different systems the order
767     was different. A call to "sort" has been inserted into RunGrepTest for the
768     approprate test as a short-term fix. In the longer term there may be an
769 ph10 100 alternative.
770 ph10 111
771 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
772 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
773     people do their own conversions for various reasons). The problems
774     concerned the use of low-level troff macros .br and .in. I have therefore
775     removed all such uses from the man pages (some were redundant, some could
776 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
777     HTML has been updated to handle .nf/.fi and to complain if it encounters
778     .br or .in.
779 ph10 111
780 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
781 ph10 123 arranged for config.h to be included in the distribution, with the name
782 ph10 111 config.h.generic, for the benefit of those who have to compile without
783     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
784    
785     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
786     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
787 ph10 127 makevp.bat for the current PCRE, using the additional files
788 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
789 ph10 111
790     6. A Windows user reported a minor discrepancy with test 2, which turned out
791     to be caused by a trailing space on an input line that had got lost in his
792 ph10 102 copy. The trailing space was an accident, so I've just removed it.
793 ph10 111
794 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
795 ph10 111 that is needed.
796    
797 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
798     as "const" (a) because they are and (b) because it helps the PHP
799     maintainers who have recently made a script to detect big data structures
800 ph10 111 in the php code that should be moved to the .rodata section. I remembered
801     to update Builducptable as well, so it won't revert if ucptable.h is ever
802 ph10 105 re-created.
803 ph10 111
804     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
805 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
806 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
807     support is not required. This saves 1.5-2K of code, which is important in
808 ph10 107 some applications.
809 ph10 111
810 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
811 ph10 111 so as not to refer to the tables, even though these functions will never be
812     called when UTF-8 support is disabled. Otherwise there are problems with a
813     shared library.
814    
815 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
816    
817     (a) It was defining its arguments as char * instead of void *.
818    
819 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
820     a long time ago when I wrote it, but is no longer the case.
821    
822 ph10 118 The emulated memove() is provided for those environments that have neither
823 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
824 ph10 118 is clearly not the case, as these two bugs were recently reported.
825 ph10 123
826 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
827 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
828     pages, and it removes trailing spaces from listed files. It also creates
829     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
830     case, it wraps all the #defines with #ifndefs. This script should be run
831 ph10 111 before "make dist".
832 ph10 123
833 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
834     with Unicode property support.
835 ph10 123
836     (a) For a maximizing quantifier, if the two different cases of the
837     character were of different lengths in their UTF-8 codings (there are
838     some cases like this - I found 11), and the matching function had to
839 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
840     were both the same length.
841 ph10 123
842     (b) When PCRE was configured to use the heap rather than the stack for
843     recursion during matching, it was not correctly preserving the data for
844     the other case of a UTF-8 character when checking ahead for a match
845     while processing a minimizing repeat. If the check also involved
846 ph10 115 matching a wide character, but failed, corruption could cause an
847     erroneous result when trying to check for a repeat of the original
848     character.
849 ph10 123
850 ph10 116 13. Some tidying changes to the testing mechanism:
851 ph10 98
852 ph10 116 (a) The RunTest script now detects the internal link size and whether there
853     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
854 ph10 123 values substituted by "configure". (The RunGrepTest script already did
855     this for UTF-8.) The configure.ac script no longer substitutes the
856     relevant variables.
857    
858 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
859     with length and offset values. This means that the output is different
860     for different internal link sizes. Test 2 is skipped for link sizes
861     other than 2 because of this, bypassing the problem. Unfortunately,
862     there was also a test in test 3 (the locale tests) that used /B and
863 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
864     I have added a new /Z option to pcretest that replaces the length and
865     offset values with spaces. This is now used to make test 3 independent
866 ph10 122 of link size. (Test 2 will be tidied up later.)
867 ph10 123
868     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
869 ph10 122 segmentation fault instead of returning the appropriate error message.
870 ph10 134
871 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
872 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
873     This doesn't seem right; it now treats the CRLF combination as the line
874     ending, and so does not match in that case. It's only a pattern such as ^$
875     that would hit this one: something like ^ABC$ would have failed after \r
876     and then tried again after \r\n.
877    
878 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
879 ph10 134 in an attempt to make files that differ only in their line terminators
880     compare equal. This works on Linux.
881 ph10 142
882 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
883     as it exited. This is now fixed, thanks to valgrind.
884 ph10 142
885 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
886 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
887     was because its rules for how to advance for /g after matching an empty
888 ph10 143 string at the end of a line did not allow for this case. They now check for
889     it specially.
890 ph10 150
891     20. pcretest is supposed to handle patterns and data of any length, by
892     extending its buffers when necessary. It was getting this wrong when the
893 ph10 147 buffer for a data line had to be extended.
894 ph10 150
895 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
896 ph10 150 CRLF as a newline sequence.
897 ph10 152
898 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
899 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
900     I have nevertheless tidied it up.
901 ph10 111
902 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
903 ph10 123
904 ph10 153 24. Added a man page for pcre-config.
905 ph10 152
906 ph10 153
907 nigel 93 Version 7.0 19-Dec-06
908     ---------------------
909    
910     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
911     moving to gcc 4.1.1.
912    
913     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
914     sys/time.h, which is documented as needed for this function. It doesn't
915     seem to matter on Linux, but it showed up on some releases of OS X.
916    
917     3. It seems that there are systems where bytes whose values are greater than
918     127 match isprint() in the "C" locale. The "C" locale should be the
919     default when a C program starts up. In most systems, only ASCII printing
920     characters match isprint(). This difference caused the output from pcretest
921     to vary, making some of the tests fail. I have changed pcretest so that:
922    
923     (a) When it is outputting text in the compiled version of a pattern, bytes
924     other than 32-126 are always shown as hex escapes.
925    
926     (b) When it is outputting text that is a matched part of a subject string,
927     it does the same, unless a different locale has been set for the match
928     (using the /L modifier). In this case, it uses isprint() to decide.
929    
930     4. Fixed a major bug that caused incorrect computation of the amount of memory
931     required for a compiled pattern when options that changed within the
932     pattern affected the logic of the preliminary scan that determines the
933     length. The relevant options are -x, and -i in UTF-8 mode. The result was
934     that the computed length was too small. The symptoms of this bug were
935     either the PCRE error "internal error: code overflow" from pcre_compile(),
936     or a glibc crash with a message such as "pcretest: free(): invalid next
937     size (fast)". Examples of patterns that provoked this bug (shown in
938     pcretest format) are:
939    
940     /(?-x: )/x
941     /(?x)(?-x: \s*#\s*)/
942     /((?i)[\x{c0}])/8
943     /(?i:[\x{c0}])/8
944    
945     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
946     is now done differently.
947    
948     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
949     wrapper classes; (b) implement a new function in the C++ scanner that is
950     more efficient than the old way of doing things because it avoids levels of
951     recursion in the regex matching; (c) add a paragraph to the documentation
952     for the FullMatch() function.
953    
954     6. The escape sequence \n was being treated as whatever was defined as
955     "newline". Not only was this contrary to the documentation, which states
956     that \n is character 10 (hex 0A), but it also went horribly wrong when
957     "newline" was defined as CRLF. This has been fixed.
958    
959     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
960     was being set to -1 for the "end of line" case (supposedly a value that no
961     character can have). Though this value is never used (the check for end of
962     line is "zero bytes in current character"), it caused compiler complaints.
963     I've changed it to 0xffffffff.
964    
965     8. In pcre_version.c, the version string was being built by a sequence of
966     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
967     string (as it is for production releases) called a macro with an empty
968     argument. The C standard says the result of this is undefined. The gcc
969     compiler treats it as an empty string (which was what was wanted) but it is
970     reported that Visual C gives an error. The source has been hacked around to
971     avoid this problem.
972    
973     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
974     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
975     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
976     of them did).
977    
978     10. Originally, pcretest opened its input and output without "b"; then I was
979     told that "b" was needed in some environments, so it was added for release
980     5.0 to both the input and output. (It makes no difference on Unix-like
981     systems.) Later I was told that it is wrong for the input on Windows. I've
982     now abstracted the modes into two macros, to make it easier to fiddle with
983     them, and removed "b" from the input mode under Windows.
984    
985     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
986    
987     12. Added -help and --help to pcretest as an official way of being reminded
988     of the options.
989    
990     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
991     and pcrecpp.cc because they annoy compilers at high warning levels.
992    
993     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
994    
995     15. Fixed an occurrence of == in configure.ac that should have been = (shell
996     scripts are not C programs :-) and which was not noticed because it works
997     on Linux.
998    
999     16. pcretest is supposed to handle any length of pattern and data line (as one
1000     line or as a continued sequence of lines) by extending its input buffer if
1001     necessary. This feature was broken for very long pattern lines, leading to
1002     a string of junk being passed to pcre_compile() if the pattern was longer
1003     than about 50K.
1004    
1005     17. I have done a major re-factoring of the way pcre_compile() computes the
1006     amount of memory needed for a compiled pattern. Previously, there was code
1007     that made a preliminary scan of the pattern in order to do this. That was
1008     OK when PCRE was new, but as the facilities have expanded, it has become
1009     harder and harder to keep it in step with the real compile phase, and there
1010     have been a number of bugs (see for example, 4 above). I have now found a
1011     cunning way of running the real compile function in a "fake" mode that
1012     enables it to compute how much memory it would need, while actually only
1013     ever using a few hundred bytes of working memory and without too many
1014     tests of the mode. This should make future maintenance and development
1015     easier. A side effect of this work is that the limit of 200 on the nesting
1016     depth of parentheses has been removed (though this was never a serious
1017     limitation, I suspect). However, there is a downside: pcre_compile() now
1018     runs more slowly than before (30% or more, depending on the pattern). I
1019     hope this isn't a big issue. There is no effect on runtime performance.
1020    
1021     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1022     newline (only possible for the last line of a file) and it was a
1023     pattern that set a locale (followed by /Lsomething), pcretest crashed.
1024    
1025     19. Added additional timing features to pcretest. (1) The -tm option now times
1026     matching only, not compiling. (2) Both -t and -tm can be followed, as a
1027     separate command line item, by a number that specifies the number of
1028     repeats to use when timing. The default is 50000; this gives better
1029     precision, but takes uncomfortably long for very large patterns.
1030    
1031     20. Extended pcre_study() to be more clever in cases where a branch of a
1032     subpattern has no definite first character. For example, (a*|b*)[cd] would
1033     previously give no result from pcre_study(). Now it recognizes that the
1034     first character must be a, b, c, or d.
1035    
1036     21. There was an incorrect error "recursive call could loop indefinitely" if
1037     a subpattern (or the entire pattern) that was being tested for matching an
1038     empty string contained only one non-empty item after a nested subpattern.
1039     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1040     incorrectly, because the \d was being skipped in the check.
1041    
1042     22. The pcretest program now has a new pattern option /B and a command line
1043     option -b, which is equivalent to adding /B to every pattern. This causes
1044     it to show the compiled bytecode, without the additional information that
1045     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1046     is the same as /B/I).
1047    
1048     23. A new optimization is now able automatically to treat some sequences such
1049     as a*b as a*+b. More specifically, if something simple (such as a character
1050     or a simple class like \d) has an unlimited quantifier, and is followed by
1051     something that cannot possibly match the quantified thing, the quantifier
1052     is automatically "possessified".
1053    
1054     24. A recursive reference to a subpattern whose number was greater than 39
1055     went wrong under certain circumstances in UTF-8 mode. This bug could also
1056     have affected the operation of pcre_study().
1057    
1058     25. Realized that a little bit of performance could be had by replacing
1059     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1060    
1061     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1062    
1063     27. Possessive quantifiers such as a++ were previously implemented by turning
1064     them into atomic groups such as ($>a+). Now they have their own opcodes,
1065     which improves performance. This includes the automatically created ones
1066     from 23 above.
1067    
1068     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1069     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1070     the first matched character to be a colon. This applied both to named and
1071     numbered groups.
1072    
1073     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1074    
1075     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1076     building PCRE on Windows easier, so I have included it in the distribution.
1077    
1078     31. There is now a check in pcretest against a ridiculously large number being
1079     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1080     loop, the loop is abandoned.
1081    
1082     32. Forward references to subpatterns in conditions such as (?(2)...) where
1083     subpattern 2 is defined later cause pcre_compile() to search forwards in
1084     the pattern for the relevant set of parentheses. This search went wrong
1085     when there were unescaped parentheses in a character class, parentheses
1086     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1087    
1088     33. "Subroutine" calls and backreferences were previously restricted to
1089     referencing subpatterns earlier in the regex. This restriction has now
1090     been removed.
1091    
1092     34. Added a number of extra features that are going to be in Perl 5.10. On the
1093     whole, these are just syntactic alternatives for features that PCRE had
1094     previously implemented using the Python syntax or my own invention. The
1095     other formats are all retained for compatibility.
1096    
1097     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1098     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1099     also .NET compatible.
1100    
1101     (b) A recursion or subroutine call to a named group can now be defined as
1102     (?&name) as well as (?P>name).
1103    
1104     (c) A backreference to a named group can now be defined as \k<name> or
1105     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1106     5.10, are also .NET compatible.
1107    
1108     (d) A conditional reference to a named group can now use the syntax
1109     (?(<name>) or (?('name') as well as (?(name).
1110    
1111     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1112     groups (named and numbered) that are never evaluated inline, but can be
1113     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1114     is always false. There may be only one alternative in such a group.
1115    
1116     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1117     as the simple (?(R). The condition is true only if the most recent
1118     recursion is that of the given number or name. It does not search out
1119     through the entire recursion stack.
1120    
1121     (g) The escape \gN or \g{N} has been added, where N is a positive or
1122     negative number, specifying an absolute or relative reference.
1123    
1124     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1125     some "unreachable code" warnings.
1126    
1127     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1128     things, this adds five new scripts.
1129    
1130     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1131     There were also incompatibilities regarding the handling of \Q..\E inside
1132     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1133     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1134    
1135     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1136     matches an empty string, and forcibly breaks the loop. There were bugs in
1137     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1138     against aaaa the result was just "a" rather than "aaaa", for example. Two
1139     separate and independent bugs (that affected different cases) have been
1140     fixed.
1141    
1142     39. Refactored the code to abolish the use of different opcodes for small
1143     capturing bracket numbers. This is a tidy that I avoided doing when I
1144     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1145     The new approach is not only tidier, it makes it possible to reduce the
1146     memory needed to fix the previous bug (38).
1147    
1148     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1149     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1150     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1151     mode.
1152    
1153     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1154     report.
1155    
1156     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1157     copy construction and assignment in the C++ wrapper.
1158    
1159     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1160     couple of bugs that could have given wrong results in the "--newline=crlf"
1161     case.
1162    
1163     44. Added a number of casts and did some reorganization of signed/unsigned int
1164     variables following suggestions from Dair Grant. Also renamed the variable
1165     "this" as "item" because it is a C++ keyword.
1166    
1167     45. Arranged for dftables to add
1168    
1169     #include "pcre_internal.h"
1170    
1171     to pcre_chartables.c because without it, gcc 4.x may remove the array
1172     definition from the final binary if PCRE is built into a static library and
1173     dead code stripping is activated.
1174    
1175     46. For an unanchored pattern, if a match attempt fails at the start of a
1176     newline sequence, and the newline setting is CRLF or ANY, and the next two
1177     characters are CRLF, advance by two characters instead of one.
1178    
1179    
1180 nigel 91 Version 6.7 04-Jul-06
1181     ---------------------
1182    
1183     1. In order to handle tests when input lines are enormously long, pcretest has
1184     been re-factored so that it automatically extends its buffers when
1185     necessary. The code is crude, but this _is_ just a test program. The
1186     default size has been increased from 32K to 50K.
1187    
1188     2. The code in pcre_study() was using the value of the re argument before
1189     testing it for NULL. (Of course, in any sensible call of the function, it
1190     won't be NULL.)
1191    
1192     3. The memmove() emulation function in pcre_internal.h, which is used on
1193     systems that lack both memmove() and bcopy() - that is, hardly ever -
1194     was missing a "static" storage class specifier.
1195    
1196     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1197     containing an extended class (one that cannot be represented by a bitmap
1198     because it contains high-valued characters or Unicode property items, e.g.
1199     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1200     pattern, but PCRE should not loop if you do not (it no longer does).
1201     [Detail: two cases were found: (a) a repeated subpattern containing an
1202     extended class; (b) a recursive reference to a subpattern that followed a
1203     previous extended class. It wasn't skipping over the extended class
1204     correctly when UTF-8 mode was not set.]
1205    
1206     5. A negated single-character class was not being recognized as fixed-length
1207     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1208     compile error "lookbehind assertion is not fixed length".
1209    
1210     6. The RunPerlTest auxiliary script was showing an unexpected difference
1211     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1212     write a Perl script that can interpret lines of an input file either as
1213     byte characters or as UTF-8, which is what "perltest" was being required to
1214     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1215     can't do is switch easily at run time between having the "use utf8;" pragma
1216     or not. In the end, I fudged it by using the RunPerlTest script to insert
1217     "use utf8;" explicitly for the UTF-8 tests.
1218    
1219     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1220     the end of the subject string, contrary to the documentation and to what
1221     Perl does. This was true of both matching functions. Now it matches only at
1222     the start of the subject and immediately after *internal* newlines.
1223    
1224     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1225     a pointer to an int instead of a pointer to an unsigned long int. This
1226     caused problems on 64-bit systems.
1227    
1228     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1229     instance of the 'standard' template library not being so standard".
1230    
1231     10. There was no check on the number of named subpatterns nor the maximum
1232     length of a subpattern name. The product of these values is used to compute
1233     the size of the memory block for a compiled pattern. By supplying a very
1234     long subpattern name and a large number of named subpatterns, the size
1235     computation could be caused to overflow. This is now prevented by limiting
1236     the length of names to 32 characters, and the number of named subpatterns
1237     to 10,000.
1238    
1239     11. Subpatterns that are repeated with specific counts have to be replicated in
1240     the compiled pattern. The size of memory for this was computed from the
1241     length of the subpattern and the repeat count. The latter is limited to
1242     65535, but there was no limit on the former, meaning that integer overflow
1243     could in principle occur. The compiled length of a repeated subpattern is
1244     now limited to 30,000 bytes in order to prevent this.
1245    
1246     12. Added the optional facility to have named substrings with the same name.
1247    
1248     13. Added the ability to use a named substring as a condition, using the
1249     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1250     are numbers (not recommended). Forward references are permitted.
1251    
1252     14. Added forward references in named backreferences (if you see what I mean).
1253    
1254     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1255     pattern could run off the end of the subject. For example, the pattern
1256     "(?s)(.{1,5})"8 did this with the subject "ab".
1257    
1258     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1259     PCRE_CASELESS was set when matching characters that were quantified with ?
1260     or *.
1261    
1262     17. A character class other than a single negated character that had a minimum
1263     but no maximum quantifier - for example [ab]{6,} - was not handled
1264     correctly by pce_dfa_exec(). It would match only one character.
1265    
1266     18. A valid (though odd) pattern that looked like a POSIX character
1267     class but used an invalid character after [ (for example [[,abc,]]) caused
1268     pcre_compile() to give the error "Failed: internal error: code overflow" or
1269     in some cases to crash with a glibc free() error. This could even happen if
1270     the pattern terminated after [[ but there just happened to be a sequence of
1271     letters, a binary zero, and a closing ] in the memory that followed.
1272    
1273     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1274     over the years. Originally (before any Unicode support), just the bottom 8
1275     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1276     output from "man perlunicode" includes this:
1277    
1278     The regular expression compiler produces polymorphic opcodes. That
1279     is, the pattern adapts to the data and automatically switches to
1280     the Unicode character scheme when presented with Unicode data--or
1281     instead uses a traditional byte scheme when presented with byte
1282     data.
1283    
1284     Sadly, a wide octal escape does not cause a switch, and in a string with
1285     no other multibyte characters, these octal escapes are treated as before.
1286     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1287     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1288     Unicode string.
1289    
1290     I have not perpetrated such confusion in PCRE. Up till now, it took just
1291     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1292     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1293     translate to the appropriate multibyte character.
1294    
1295     29. Applied some refactoring to reduce the number of warnings from Microsoft
1296     and Borland compilers. This has included removing the fudge introduced
1297     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1298     a warning about an unused variable.
1299    
1300     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1301     characters since release 4.0, because Perl (from release 5.004) does not.
1302     [Or at least, is documented not to: some releases seem to be in conflict
1303     with the documentation.] However, when a pattern was studied with
1304     pcre_study() and all its branches started with \s, PCRE still included VT
1305     as a possible starting character. Of course, this did no harm; it just
1306     caused an unnecessary match attempt.
1307    
1308     22. Removed a now-redundant internal flag bit that recorded the fact that case
1309     dependency changed within the pattern. This was once needed for "required
1310     byte" processing, but is no longer used. This recovers a now-scarce options
1311     bit. Also moved the least significant internal flag bit to the most-
1312     significant bit of the word, which was not previously used (hangover from
1313     the days when it was an int rather than a uint) to free up another bit for
1314     the future.
1315    
1316     23. Added support for CRLF line endings as well as CR and LF. As well as the
1317     default being selectable at build time, it can now be changed at runtime
1318     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1319     specify that it is scanning data with non-default line endings.
1320    
1321     24. Changed the definition of CXXLINK to make it agree with the definition of
1322     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1323    
1324     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1325     recursions. This makes a big different to stack usage for some patterns.
1326    
1327     26. If a subpattern containing a named recursion or subroutine reference such
1328     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1329     the space required for the compiled pattern went wrong and gave too small a
1330     value. Depending on the environment, this could lead to "Failed: internal
1331     error: code overflow at offset 49" or "glibc detected double free or
1332     corruption" errors.
1333    
1334     27. Applied patches from Google (a) to support the new newline modes and (b) to
1335     advance over multibyte UTF-8 characters in GlobalReplace.
1336    
1337     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1338     difference for some implementation of PCRE in some Windows version.
1339    
1340     29. Added some extra testing facilities to pcretest:
1341    
1342     \q<number> in a data line sets the "match limit" value
1343     \Q<number> in a data line sets the "match recursion limt" value
1344     -S <number> sets the stack size, where <number> is in megabytes
1345    
1346     The -S option isn't available for Windows.
1347    
1348    
1349 nigel 89 Version 6.6 06-Feb-06
1350     ---------------------
1351    
1352     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1353     in pcreposix.h. I have copied the definition from pcre.h.
1354    
1355     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1356     because pcre.h is no longer a built file.
1357    
1358     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1359     not normally included in the compiled code.
1360    
1361    
1362 nigel 87 Version 6.5 01-Feb-06
1363     ---------------------
1364    
1365     1. When using the partial match feature with pcre_dfa_exec(), it was not
1366     anchoring the second and subsequent partial matches at the new starting
1367     point. This could lead to incorrect results. For example, with the pattern
1368     /1234/, partially matching against "123" and then "a4" gave a match.
1369    
1370     2. Changes to pcregrep:
1371    
1372     (a) All non-match returns from pcre_exec() were being treated as failures
1373     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1374     error message is output. Some extra information is given for the
1375     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1376     probably the only errors that are likely to be caused by users (by
1377     specifying a regex that has nested indefinite repeats, for instance).
1378     If there are more than 20 of these errors, pcregrep is abandoned.
1379    
1380     (b) A binary zero was treated as data while matching, but terminated the
1381     output line if it was written out. This has been fixed: binary zeroes
1382     are now no different to any other data bytes.
1383    
1384     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1385     used to set a locale for matching. The --locale=xxxx long option has
1386     been added (no short equivalent) to specify a locale explicitly on the
1387     pcregrep command, overriding the environment variables.
1388    
1389     (d) When -B was used with -n, some line numbers in the output were one less
1390     than they should have been.
1391    
1392     (e) Added the -o (--only-matching) option.
1393    
1394     (f) If -A or -C was used with -c (count only), some lines of context were
1395     accidentally printed for the final match.
1396    
1397     (g) Added the -H (--with-filename) option.
1398    
1399     (h) The combination of options -rh failed to suppress file names for files
1400     that were found from directory arguments.
1401    
1402     (i) Added the -D (--devices) and -d (--directories) options.
1403    
1404     (j) Added the -F (--fixed-strings) option.
1405    
1406     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1407    
1408     (l) Added the --colo(u)r option.
1409    
1410     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1411     is not present by default.
1412    
1413     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1414     items such as (?R) or (?1), when the recursion could match a number of
1415     alternatives. If it matched one of the alternatives, but subsequently,
1416     outside the recursion, there was a failure, the code tried to back up into
1417     the recursion. However, because of the way PCRE is implemented, this is not
1418     possible, and the result was an incorrect result from the match.
1419    
1420     In order to prevent this happening, the specification of recursion has
1421     been changed so that all such subpatterns are automatically treated as
1422     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1423    
1424     4. I had overlooked the fact that, in some locales, there are characters for
1425     which isalpha() is true but neither isupper() nor islower() are true. In
1426     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1427     and ordfeminine) are like this. This affected the treatment of \w and \W
1428     when they appeared in character classes, but not when they appeared outside
1429     a character class. The bit map for "word" characters is now created
1430     separately from the results of isalnum() instead of just taking it from the
1431     upper, lower, and digit maps. (Plus the underscore character, of course.)
1432    
1433     5. The above bug also affected the handling of POSIX character classes such as
1434     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1435     permanent tables. Instead, the bit maps for such a class were previously
1436     created as the appropriate unions of the upper, lower, and digit bitmaps.
1437     Now they are created by subtraction from the [[:word:]] class, which has
1438     its own bitmap.
1439    
1440     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1441     It is created by subtracting the vertical space characters (\x09, \x0a,
1442     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1443     subtraction was done in the overall bitmap for a character class, meaning
1444     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1445     be recognized. This bug has been fixed.
1446    
1447     7. Patches from the folks at Google:
1448    
1449     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1450     real life, but is still worth protecting against".
1451    
1452     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1453     regular expressions".
1454    
1455     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1456     have it.
1457    
1458     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1459     "configure" and the latter not, in order to fix a problem somebody had
1460     with compiling the Arg class on HP-UX.
1461    
1462     (e) Improve the error-handling of the C++ wrapper a little bit.
1463    
1464     (f) New tests for checking recursion limiting.
1465    
1466     8. The pcre_memmove() function, which is used only if the environment does not
1467     have a standard memmove() function (and is therefore rarely compiled),
1468     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1469     returning a result (though PCRE never actually uses the result).
1470    
1471     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1472     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1473     returned instead of calling malloc() with an overflowing number that would
1474     most likely cause subsequent chaos.
1475    
1476     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1477    
1478     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1479     with this option is matched, the nmatch and pmatch options of regexec() are
1480     ignored.
1481    
1482     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1483     provided in case anyone wants to the the POSIX interface with UTF-8
1484     strings.
1485    
1486     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1487     C++ linking (needed for some HP-UX environments).
1488    
1489     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1490     (unused parameter) and in the pcre_printint() function (omitted "default"
1491     switch label when the default is to do nothing).
1492    
1493     15. Added some code to make it possible, when PCRE is compiled as a C++
1494     library, to replace subject pointers for pcre_exec() with a smart pointer
1495     class, thus making it possible to process discontinuous strings.
1496    
1497     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1498     much the same function. They were added by different people who were trying
1499     to make PCRE easy to compile on non-Unix systems. It has been suggested
1500     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1501     for compiling on Windows systems. I have therefore replaced it with
1502     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1503     defaults to "extern" for C or "extern C" for C++, which works fine on
1504     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1505     SCOPE with something explicit in config.h. In addition:
1506    
1507     (a) pcreposix.h still had just "extern" instead of either of these macros;
1508     I have replaced it with PCRE_DATA_SCOPE.
1509    
1510     (b) Functions such as _pcre_xclass(), which are internal to the library,
1511     but external in the C sense, all had PCRE_EXPORT in their definitions.
1512     This is apparently wrong for the Windows case, so I have removed it.
1513     (It makes no difference on Unix-like systems.)
1514    
1515     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1516     of recursive calls to match(). This is different to MATCH_LIMIT because
1517     that limits the total number of calls to match(), not all of which increase
1518     the depth of recursion. Limiting the recursion depth limits the amount of
1519     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1520     when PCRE is compiled, and changed at run time. A patch from Google adds
1521     this functionality to the C++ interface.
1522    
1523     18. Changes to the handling of Unicode character properties:
1524    
1525     (a) Updated the table to Unicode 4.1.0.
1526    
1527     (b) Recognize characters that are not in the table as "Cn" (undefined).
1528    
1529     (c) I revised the way the table is implemented to a much improved format
1530     which includes recognition of ranges. It now supports the ranges that
1531     are defined in UnicodeData.txt, and it also amalgamates other
1532     characters into ranges. This has reduced the number of entries in the
1533     table from around 16,000 to around 3,000, thus reducing its size
1534     considerably. I realized I did not need to use a tree structure after
1535     all - a binary chop search is just as efficient. Having reduced the
1536     number of entries, I extended their size from 6 bytes to 8 bytes to
1537     allow for more data.
1538    
1539     (d) Added support for Unicode script names via properties such as \p{Han}.
1540    
1541     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1542     matching that character.
1543    
1544     20. When matching a repeated Unicode property with a minimum greater than zero,
1545     (for example \pL{2,}), PCRE could look past the end of the subject if it
1546     reached it while seeking the minimum number of characters. This could
1547     happen only if some of the characters were more than one byte long, because
1548     there is a check for at least the minimum number of bytes.
1549    
1550     21. Refactored the implementation of \p and \P so as to be more general, to
1551     allow for more different types of property in future. This has changed the
1552     compiled form incompatibly. Anybody with saved compiled patterns that use
1553     \p or \P will have to recompile them.
1554    
1555     22. Added "Any" and "L&" to the supported property types.
1556    
1557     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1558     but give a compile time error if the value is greater than 0xff.
1559    
1560     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1561     accidentally not being installed or uninstalled.
1562    
1563     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1564     made were to insert the current release number. This seemed silly, because
1565     it made things harder for people building PCRE on systems that don't run
1566     "configure". I have turned pcre.h into a distributed file, no longer built
1567     by "configure", with the version identification directly included. There is
1568     no longer a pcre.h.in file.
1569    
1570     However, this change necessitated a change to the pcre-config script as
1571     well. It is built from pcre-config.in, and one of the substitutions was the
1572     release number. I have updated configure.ac so that ./configure now finds
1573     the release number by grepping pcre.h.
1574    
1575     26. Added the ability to run the tests under valgrind.
1576    
1577    
1578 nigel 85 Version 6.4 05-Sep-05
1579     ---------------------
1580    
1581     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1582     "--" to be printed when multiple files were scanned, even when none of the
1583     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1584     consider it to be a bug, and have restored the previous behaviour.
1585    
1586     2. A couple of code tidies to get rid of compiler warnings.
1587    
1588     3. The pcretest program used to cheat by referring to symbols in the library
1589     whose names begin with _pcre_. These are internal symbols that are not
1590     really supposed to be visible externally, and in some environments it is
1591     possible to suppress them. The cheating is now confined to including
1592     certain files from the library's source, which is a bit cleaner.
1593    
1594     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1595     file's purpose clearer.
1596    
1597     5. Reorganized pcre_ucp_findchar().
1598    
1599    
1600 nigel 83 Version 6.3 15-Aug-05
1601     ---------------------
1602    
1603     1. The file libpcre.pc.in did not have general read permission in the tarball.
1604    
1605     2. There were some problems when building without C++ support:
1606    
1607     (a) If C++ support was not built, "make install" and "make test" still
1608     tried to test it.
1609    
1610     (b) There were problems when the value of CXX was explicitly set. Some
1611     changes have been made to try to fix these, and ...
1612    
1613     (c) --disable-cpp can now be used to explicitly disable C++ support.
1614    
1615     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1616     backslash in a target when C++ was disabled. This confuses some
1617     versions of "make", apparently. Using an intermediate variable solves
1618     this. (Same for CPP_LOBJ.)
1619    
1620     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1621     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1622     necessary on certain architectures.
1623    
1624     4. Added a setting of -export-symbols-regex to the link command to remove
1625     those symbols that are exported in the C sense, but actually are local
1626     within the library, and not documented. Their names all begin with
1627     "_pcre_". This is not a perfect job, because (a) we have to except some
1628     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1629     available (and never for static libraries). I have made a note to try to
1630     find a way round (a) in the future.
1631    
1632    
1633 nigel 81 Version 6.2 01-Aug-05
1634     ---------------------
1635    
1636     1. There was no test for integer overflow of quantifier values. A construction
1637     such as {1111111111111111} would give undefined results. What is worse, if
1638     a minimum quantifier for a parenthesized subpattern overflowed and became
1639     negative, the calculation of the memory size went wrong. This could have
1640     led to memory overwriting.
1641    
1642     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1643    
1644     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1645     operating environments where this matters.
1646    
1647     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1648     PCRE options from within the C++ wrapper.
1649    
1650     5. Named capturing subpatterns were not being correctly counted when a pattern
1651     was compiled. This caused two problems: (a) If there were more than 100
1652     such subpatterns, the calculation of the memory needed for the whole
1653     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1654     back references of the form \12, where the number was greater than 9, were
1655     not recognized as back references, even though there were sufficient
1656     previous subpatterns.
1657    
1658     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1659     versions of gcc, e.g. 2.95.4.
1660    
1661    
1662 nigel 79 Version 6.1 21-Jun-05
1663     ---------------------
1664    
1665     1. There was one reference to the variable "posix" in pcretest.c that was not
1666     surrounded by "#if !defined NOPOSIX".
1667    
1668     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1669     the cross-check on the old pcre_info() function, for the benefit of the
1670     cut-down version of PCRE that is currently imported into Exim.
1671    
1672     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1673     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1674     patterns that start (?i) but I don't think that matters. The use of (?i) is
1675     just an example; this all applies to the other options as well.
1676    
1677     4. Since libtool seems to echo the compile commands it is issuing, the output
1678     from "make" can be reduced a bit by putting "@" in front of each libtool
1679     compile command.
1680    
1681     5. Patch from the folks at Google for configure.in to be a bit more thorough
1682     in checking for a suitable C++ installation before trying to compile the
1683     C++ stuff. This should fix a reported problem when a compiler was present,
1684     but no suitable headers.
1685    
1686     6. The man pages all had just "PCRE" as their title. I have changed them to
1687     be the relevant file name. I have also arranged that these names are
1688     retained in the file doc/pcre.txt, which is a concatenation in text format
1689     of all the man pages except the little individual ones for each function.
1690    
1691     7. The NON-UNIX-USE file had not been updated for the different set of source
1692     files that come with release 6. I also added a few comments about the C++
1693     wrapper.
1694    
1695    
1696 nigel 77 Version 6.0 07-Jun-05
1697     ---------------------
1698    
1699     1. Some minor internal re-organization to help with my DFA experiments.
1700    
1701     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1702     didn't matter for the library itself when fully configured, but did matter
1703     when compiling without UCP support, or within Exim, where the ucp files are
1704     not imported.
1705    
1706     3. Refactoring of the library code to split up the various functions into
1707     different source modules. The addition of the new DFA matching code (see
1708     below) to a single monolithic source would have made it really too
1709     unwieldy, quite apart from causing all the code to be include in a
1710     statically linked application, when only some functions are used. This is
1711     relevant even without the DFA addition now that patterns can be compiled in
1712     one application and matched in another.
1713    
1714     The downside of splitting up is that there have to be some external
1715     functions and data tables that are used internally in different modules of
1716     the library but which are not part of the API. These have all had their
1717     names changed to start with "_pcre_" so that they are unlikely to clash
1718     with other external names.
1719    
1720     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1721     a different (DFA) algorithm. Although it is slower than the original
1722     function, it does have some advantages for certain types of matching
1723     problem.
1724    
1725     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1726     including restarting after a partial match.
1727    
1728     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1729     defined when compiling for Windows was sent to me. I have put it into the
1730     code, though I have no means of testing or verifying it.
1731    
1732     7. Added the pcre_refcount() auxiliary function.
1733    
1734     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1735     match before or at the first newline in the subject string. In pcretest,
1736     the /f option on a pattern can be used to set this.
1737    
1738     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1739     would behave wrongly. This has been present in PCRE since release 4.0.
1740    
1741     10. A number of changes to the pcregrep command:
1742    
1743     (a) Refactored how -x works; insert ^(...)$ instead of setting
1744     PCRE_ANCHORED and checking the length, in preparation for adding
1745     something similar for -w.
1746    
1747     (b) Added the -w (match as a word) option.
1748    
1749     (c) Refactored the way lines are read and buffered so as to have more
1750     than one at a time available.
1751    
1752     (d) Implemented a pcregrep test script.
1753    
1754     (e) Added the -M (multiline match) option. This allows patterns to match
1755     over several lines of the subject. The buffering ensures that at least
1756     8K, or the rest of the document (whichever is the shorter) is available
1757     for matching (and similarly the previous 8K for lookbehind assertions).
1758    
1759     (f) Changed the --help output so that it now says
1760    
1761     -w, --word-regex(p)
1762    
1763     instead of two lines, one with "regex" and the other with "regexp"
1764     because that confused at least one person since the short forms are the
1765     same. (This required a bit of code, as the output is generated
1766     automatically from a table. It wasn't just a text change.)
1767    
1768     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1769     option but starts with a hyphen. Could be a pattern or a path name
1770     starting with a hyphen, for instance.
1771    
1772     (h) "-" can be given as a file name to represent stdin.
1773    
1774     (i) When file names are being printed, "(standard input)" is used for
1775     the standard input, for compatibility with GNU grep. Previously
1776     "<stdin>" was used.
1777    
1778     (j) The option --label=xxx can be used to supply a name to be used for
1779     stdin when file names are being printed. There is no short form.
1780    
1781     (k) Re-factored the options decoding logic because we are going to add
1782     two more options that take data. Such options can now be given in four
1783     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1784    
1785     (l) Added the -A, -B, and -C options for requesting that lines of context
1786     around matches be printed.
1787    
1788     (m) Added the -L option to print the names of files that do not contain
1789     any matching lines, that is, the complement of -l.
1790    
1791     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1792     continue to scan other files.
1793    
1794     (o) The -s option was incorrectly implemented. For compatibility with other
1795     greps, it now suppresses the error message for a non-existent or non-
1796     accessible file (but not the return code). There is a new option called
1797     -q that suppresses the output of matching lines, which was what -s was
1798     previously doing.
1799    
1800     (p) Added --include and --exclude options to specify files for inclusion
1801     and exclusion when recursing.
1802    
1803     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1804     Hopefully, it now does.
1805    
1806     12. Missing cast in pcre_study().
1807    
1808     13. Added an "uninstall" target to the makefile.
1809    
1810     14. Replaced "extern" in the function prototypes in Makefile.in with
1811     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1812     world, but is set differently for Windows.
1813    
1814     15. Added a second compiling function called pcre_compile2(). The only
1815     difference is that it has an extra argument, which is a pointer to an
1816     integer error code. When there is a compile-time failure, this is set
1817     non-zero, in addition to the error test pointer being set to point to an
1818     error message. The new argument may be NULL if no error number is required
1819     (but then you may as well call pcre_compile(), which is now just a
1820     wrapper). This facility is provided because some applications need a
1821     numeric error indication, but it has also enabled me to tidy up the way
1822     compile-time errors are handled in the POSIX wrapper.
1823    
1824     16. Added VPATH=.libs to the makefile; this should help when building with one
1825     prefix path and installing with another. (Or so I'm told by someone who
1826     knows more about this stuff than I do.)
1827    
1828     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1829     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1830     match everything, including newlines. This is not POSIX-compatible, but
1831     somebody wanted the feature. From pcretest it can be activated by using
1832     both the P and the s flags.
1833    
1834     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1835    
1836     19. libpcre.pc was being incorrectly installed as executable.
1837    
1838     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1839     it now also looks for '\r' so that it will work unmodified on Windows.
1840    
1841     21. Added Google's contributed C++ wrapper to the distribution.
1842    
1843     22. Added some untidy missing memory free() calls in pcretest, to keep
1844     Electric Fence happy when testing.
1845    
1846    
1847    
1848 nigel 75 Version 5.0 13-Sep-04
1849     ---------------------
1850    
1851     1. Internal change: literal characters are no longer packed up into items
1852     containing multiple characters in a single byte-string. Each character
1853     is now matched using a separate opcode. However, there may be more than one
1854     byte in the character in UTF-8 mode.
1855    
1856     2. The pcre_callout_block structure has two new fields: pattern_position and
1857     next_item_length. These contain the offset in the pattern to the next match
1858     item, and its length, respectively.
1859    
1860     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1861     insertion of callouts before each pattern item. Added the /C option to
1862     pcretest to make use of this.
1863    
1864     4. On the advice of a Windows user, the lines
1865    
1866     #if defined(_WIN32) || defined(WIN32)
1867     _setmode( _fileno( stdout ), 0x8000 );
1868     #endif /* defined(_WIN32) || defined(WIN32) */
1869    
1870     have been added to the source of pcretest. This apparently does useful
1871     magic in relation to line terminators.
1872    
1873     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1874     for the benefit of those environments where the "b" makes a difference.
1875    
1876     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1877     to know about it. I have put a hack into configure.in that adds in code
1878     to set GCC=yes if CC=icc. This seems to end up at a point in the
1879     generated configure script that is early enough to affect the setting of
1880     compiler options, which is what is needed, but I have no means of testing
1881     whether it really works. (The user who reported this had patched the
1882     generated configure script, which of course I cannot do.)
1883    
1884     LATER: After change 22 below (new libtool files), the configure script
1885     seems to know about icc (and also ecc). Therefore, I have commented out
1886     this hack in configure.in.
1887    
1888     7. Added support for pkg-config (2 patches were sent in).
1889    
1890     8. Negated POSIX character classes that used a combination of internal tables
1891     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1892     [[:^ascii]]. Typically, they would match almost any characters. The other
1893     POSIX classes were not broken in this way.
1894    
1895     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1896     to find the match, as PCRE was deluded into thinking that the match had to
1897     start at the start point or following a newline. The same bug applied to
1898     patterns with negative forward assertions or any backward assertions
1899     preceding ".*" at the start, unless the pattern required a fixed first
1900     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1901    
1902     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1903     starting at the last subject character, bytes beyond the end of the subject
1904     string were read.
1905    
1906     11. Renamed the variable "class" as "classbits" to make life easier for C++
1907     users. (Previously there was a macro definition, but it apparently wasn't
1908     enough.)
1909    
1910     12. Added the new field "tables" to the extra data so that tables can be passed
1911     in at exec time, or the internal tables can be re-selected. This allows
1912     a compiled regex to be saved and re-used at a later time by a different
1913     program that might have everything at different addresses.
1914    
1915     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1916     -R library as well as a -L library.
1917    
1918     14. The debugging options of pcretest (-d on the command line or D on a
1919     pattern) showed incorrect output for anything following an extended class
1920     that contained multibyte characters and which was followed by a quantifier.
1921    
1922     15. Added optional support for general category Unicode character properties
1923     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1924     support. It adds about 90K to the size of the library. The meanings of the
1925     inbuilt class escapes such as \d and \s have NOT been changed.
1926    
1927     16. Updated pcredemo.c to include calls to free() to release the memory for the
1928     compiled pattern.
1929    
1930     17. The generated file chartables.c was being created in the source directory
1931     instead of in the building directory. This caused the build to fail if the
1932     source directory was different from the building directory, and was
1933     read-only.
1934    
1935     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1936     file. No doubt somebody will tell me if they don't make sense... Also added
1937     Dan Mooney's comments about building on OpenVMS.
1938    
1939     19. Added support for partial matching via the PCRE_PARTIAL option for
1940     pcre_exec() and the \P data escape in pcretest.
1941    
1942     20. Extended pcretest with 3 new pattern features:
1943    
1944     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1945     write the compiled pattern to the file whose name is "rest-of-line".
1946     This is a straight binary dump of the data, with the saved pointer to
1947     the character tables forced to be NULL. The study data, if any, is
1948     written too. After writing, pcretest reads a new pattern.
1949    
1950     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1951     compiled pattern from the given file. There must not be any
1952     occurrences of "<" in the file name (pretty unlikely); if there are,
1953     pcretest will instead treat the initial "<" as a pattern delimiter.
1954     After reading in the pattern, pcretest goes on to read data lines as
1955     usual.
1956    
1957     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1958     and 16-bit fields in a compiled pattern, to simulate a pattern that
1959     was compiled on a host of opposite endianness.
1960    
1961     21. The pcre-exec() function can now cope with patterns that were compiled on
1962     hosts of opposite endianness, with this restriction:
1963    
1964     As for any compiled expression that is saved and used later, the tables
1965     pointer field cannot be preserved; the extra_data field in the arguments
1966     to pcre_exec() should be used to pass in a tables address if a value
1967     other than the default internal tables were used at compile time.
1968    
1969     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1970     now diagnosed as an error. Previously, most of the time, a negative number
1971     would have been treated as zero, but if in addition "ovector" was passed as
1972     NULL, a crash could occur.
1973    
1974     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1975     new versions from the libtool 1.5 distribution (the last one is a copy of
1976     a file called libtool.m4). This seems to have fixed the need to patch
1977     "configure" to support Darwin 1.3 (which I used to do). However, I still
1978     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1979     workstation).
1980    
1981     24. Changed the PCRE licence to be the more standard "BSD" licence.
1982    
1983    
1984 nigel 73 Version 4.5 01-Dec-03
1985     ---------------------
1986    
1987     1. There has been some re-arrangement of the code for the match() function so
1988     that it can be compiled in a version that does not call itself recursively.
1989     Instead, it keeps those local variables that need separate instances for
1990     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1991     needs to "recurse". Keeping track of where control must go is done by means
1992     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1993     hide most of the details from the main code, and operates only if
1994     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1995     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1996     operating.
1997    
1998     To make it easier for callers to provide specially tailored get/free
1999     functions for this usage, two new functions, pcre_stack_malloc, and
2000     pcre_stack_free, are used. They are always called in strict stacking order,
2001     and the size of block requested is always the same.
2002    
2003     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2004     PCRE has been compiled to use the stack or the heap for recursion. The
2005     -C option of pcretest uses this to show which version is compiled.
2006    
2007     A new data escape \S, is added to pcretest; it causes the amounts of store
2008     obtained and freed by both kinds of malloc/free at match time to be added
2009     to the output.
2010    
2011     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2012     what's available on my current Linux desktop machine.
2013    
2014     3. When matching a UTF-8 string, the test for a valid string at the start has
2015     been extended. If start_offset is not zero, PCRE now checks that it points
2016     to a byte that is the start of a UTF-8 character. If not, it returns
2017     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2018     this is necessary because there may be backward assertions in the pattern.
2019     When matching the same subject several times, it may save resources to use
2020     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2021    
2022     4. The code for checking the validity of UTF-8 strings has been tightened so
2023     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2024     containing "overlong sequences".
2025    
2026     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2027     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2028     should have been "&", but it just so happened that all the cases this let
2029     through by mistake were picked up later in the function.
2030    
2031     6. I had used a variable called "isblank" - this is a C99 function, causing
2032     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2033    
2034     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2035     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2036     so the version is shown; (c) stop "make test" echoing "./RunTest".
2037    
2038     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2039    
2040     9. The prototype for memmove() for systems that don't have it was using
2041     size_t, but the inclusion of the header that defines size_t was later. I've
2042     moved the #includes for the C headers earlier to avoid this.
2043    
2044     10. Added some adjustments to the code to make it easier to compiler on certain
2045     special systems:
2046    
2047     (a) Some "const" qualifiers were missing.
2048     (b) Added the macro EXPORT before all exported functions; by default this
2049     is defined to be empty.
2050     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2051     that it reads its output file name as an argument instead of writing
2052     to the standard output and assuming this can be redirected.
2053    
2054     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2055     class containing characters with values greater than 255, PCRE compilation
2056     went into a loop.
2057    
2058     12. A recursive reference to a subpattern that was within another subpattern
2059     that had a minimum quantifier of zero caused PCRE to crash. For example,
2060     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2061     recursion. If the recursively-called subpattern itself had a zero repeat,
2062     that was OK.
2063    
2064     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2065     buffer into which it was copied (for escape processing) was still set at
2066     1024, so long lines caused crashes.
2067    
2068     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2069     "internal error: code overflow...". This applied to any character class
2070     that was followed by a possessive quantifier.
2071    
2072     15. Modified the Makefile to add libpcre.la as a prerequisite for
2073     libpcreposix.la because I was told this is needed for a parallel build to
2074     work.
2075    
2076     16. If a pattern that contained .* following optional items at the start was
2077     studied, the wrong optimizing data was generated, leading to matching
2078     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2079     matching string must start with a or b or c. The correct conclusion for
2080     this pattern is that a match can start with any character.
2081    
2082    
2083 nigel 71 Version 4.4 13-Aug-03
2084     ---------------------
2085    
2086     1. In UTF-8 mode, a character class containing characters with values between
2087     127 and 255 was not handled correctly if the compiled pattern was studied.
2088     In fixing this, I have also improved the studying algorithm for such
2089     classes (slightly).
2090    
2091     2. Three internal functions had redundant arguments passed to them. Removal
2092     might give a very teeny performance improvement.
2093    
2094     3. Documentation bug: the value of the capture_top field in a callout is *one
2095     more than* the number of the hightest numbered captured substring.
2096    
2097     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2098     in incorrectly linking with a previously installed version. They now link
2099     explicitly with libpcre.la.
2100    
2101     5. configure.in no longer needs to recognize Cygwin specially.
2102    
2103     6. A problem in pcre.in for Windows platforms is fixed.
2104    
2105     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2106     pcretest, it used to include the size of the study block as part of its
2107     output. Unfortunately, the structure contains a field that has a different
2108     size on different hardware architectures. This meant that the tests that
2109     showed this size failed. As the block is currently always of a fixed size,
2110     this information isn't actually particularly useful in pcretest output, so
2111     I have just removed it.
2112    
2113     8. Three pre-processor statements accidentally did not start in column 1.
2114     Sadly, there are *still* compilers around that complain, even though
2115     standard C has not required this for well over a decade. Sigh.
2116    
2117     9. In pcretest, the code for checking callouts passed small integers in the
2118     callout_data field, which is a void * field. However, some picky compilers
2119     complained about the casts involved for this on 64-bit systems. Now
2120     pcretest passes the address of the small integer instead, which should get
2121     rid of the warnings.
2122    
2123     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2124     both compile and run time, and gives an error if an invalid UTF-8 sequence
2125     is found. There is a option for disabling this check in cases where the
2126     string is known to be correct and/or the maximum performance is wanted.
2127    
2128     11. In response to a bug report, I changed one line in Makefile.in from
2129    
2130     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2131     to
2132     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2133    
2134     to look similar to other lines, but I have no way of telling whether this
2135     is the right thing to do, as I do not use Windows. No doubt I'll get told
2136     if it's wrong...
2137    
2138    
2139 nigel 69 Version 4.3 21-May-03
2140     ---------------------
2141    
2142     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2143     Makefile.
2144    
2145     2. Some refactoring to improve the quality of the code:
2146    
2147     (i) The utf8_table... variables are now declared "const".
2148    
2149     (ii) The code for \cx, which used the "case flipping" table to upper case
2150     lower case letters, now just substracts 32. This is ASCII-specific,
2151     but the whole concept of \cx is ASCII-specific, so it seems
2152     reasonable.
2153    
2154     (iii) PCRE was using its character types table to recognize decimal and
2155     hexadecimal digits in the pattern. This is silly, because it handles
2156     only 0-9, a-f, and A-F, but the character types table is locale-
2157     specific, which means strange things might happen. A private
2158     table is now used for this - though it costs 256 bytes, a table is
2159     much faster than multiple explicit tests. Of course, the standard
2160     character types table is still used for matching digits in subject
2161     strings against \d.
2162    
2163     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2164     ending in _t are). So I've renamed it as ESC_tee.
2165    
2166     3. The first argument for regexec() in the POSIX wrapper should have been
2167     defined as "const".
2168    
2169     4. Changed pcretest to use malloc() for its buffers so that they can be
2170     Electric Fenced for debugging.
2171    
2172     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2173     to read one or more bytes before the start of the subject string. Often this
2174     had no effect on PCRE's behaviour, but in some circumstances it could
2175     provoke a segmentation fault.
2176    
2177     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2178     to try to read one or more bytes before the start of the subject string.
2179    
2180     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2181     UTF-8 support could misbehave in various ways if the subject string
2182     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2183     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2184     back over UTF-8 characters.)
2185    
2186    
2187 nigel 67 Version 4.2 14-Apr-03
2188     ---------------------
2189    
2190     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2191    
2192     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2193     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2194     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2195     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2196     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2197     and BUILD_EXEEXT
2198     Note: automatic setting of the BUILD variables is not yet working
2199     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2200     compile-time but not at link-time
2201     [LINK]: use for linking executables only
2202     make different versions for Windows and non-Windows
2203     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2204     libraries
2205     [LINK_FOR_BUILD]: new variable
2206     [OBJEXT]: use throughout
2207     [EXEEXT]: use throughout
2208     <winshared>: new target
2209     <wininstall>: new target
2210     <dftables.o>: use native compiler
2211     <dftables>: use native linker
2212     <install>: handle Windows platform correctly
2213     <clean>: ditto
2214     <check>: ditto
2215     copy DLL to top builddir before testing
2216    
2217     As part of these changes, -no-undefined was removed again. This was reported
2218     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2219     in any case.
2220    
2221     3. Some tidies to get rid of compiler warnings:
2222    
2223     . In the match_data structure, match_limit was an unsigned long int, whereas
2224     match_call_count was an int. I've made them both unsigned long ints.
2225    
2226     . In pcretest the fact that a const uschar * doesn't automatically cast to
2227     a void * provoked a warning.
2228    
2229     . Turning on some more compiler warnings threw up some "shadow" variables
2230     and a few more missing casts.
2231    
2232     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2233     option, a class that contained a single character with a value between 128
2234     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2235    
2236     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2237     option, a class that contained several characters, but with at least one
2238     whose value was between 128 and 255 caused PCRE to crash.
2239    
2240    
2241 nigel 65 Version 4.1 12-Mar-03
2242     ---------------------
2243 nigel 63
2244 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2245     needed, and a string in dftables.c that was longer than standard compilers are
2246     required to support.
2247    
2248     2. Compiling with Sun's compiler found a few more places where the code could
2249     be tidied up in order to avoid warnings.
2250    
2251     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2252     first of these names is deprecated in the latest Autoconf in favour of the name
2253     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2254     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2255     analogy I have changed it to CFLAGS_FOR_BUILD.
2256    
2257     4. Added -no-undefined to the linking command in the Makefile, because this is
2258     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2259     linking step for the pcreposix library.
2260    
2261     5. PCRE was failing to diagnose the case of two named groups with the same
2262     name.
2263    
2264     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2265     literal character that is needed in the subject for a match, and scans along to
2266     ensure that it is present before embarking on the full matching process. This
2267     saves time in cases of nested unlimited repeats that are never going to match.
2268     Problem: the scan can take a lot of time if the subject is very long (e.g.
2269     megabytes), thus penalizing straightforward matches. It is now done only if the
2270     amount of subject to be scanned is less than 1000 bytes.
2271    
2272     7. A lesser problem with the same optimization is that it was recording the
2273     first character of an anchored pattern as "needed", thus provoking a search
2274     right along the subject, even when the first match of the pattern was going to
2275     fail. The "needed" character is now not set for anchored patterns, unless it
2276     follows something in the pattern that is of non-fixed length. Thus, it still
2277     fulfils its original purpose of finding quick non-matches in cases of nested
2278     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2279    
2280    
2281     Version 4.0 17-Feb-03
2282     ---------------------
2283    
2284 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2285     extended to the end of string, PCRE compiled incorrect data. This could lead to
2286     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2287    
2288     2. Moved to autoconf 2.53 and libtool 1.4.2.
2289    
2290     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2291     the special perltest8 script is no longer needed - all the tests can be run
2292     from a single perltest script.
2293    
2294     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2295     by \s. It has now been removed in PCRE. This means it isn't recognized as
2296     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2297     class [:space:] *does* include VT, thereby creating a mess.
2298    
2299     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2300     space and tab.
2301    
2302     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2303     its new features into the main test script, reducing the number of scripts.
2304    
2305     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2306     were backward compatible, and made the (?i) apply to the whole pattern, as if
2307     /i were given. Now it behaves more logically, and applies the option setting
2308     only to what follows. PCRE has been changed to follow suit. However, if it
2309     finds options settings right at the start of the pattern, it extracts them into
2310     the global options, as before. Thus, they show up in the info data.
2311    
2312     8. Added support for the \Q...\E escape sequence. Characters in between are
2313     treated as literals. This is slightly different from Perl in that $ and @ are
2314     also handled as literals inside the quotes. In Perl, they will cause variable
2315     interpolation. Note the following examples:
2316    
2317     Pattern PCRE matches Perl matches
2318    
2319     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2320     \Qabc\$xyz\E abc\$xyz abc\$xyz
2321     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2322    
2323     For compatibility with Perl, \Q...\E sequences are recognized inside character
2324     classes as well as outside them.
2325    
2326     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2327     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2328     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2329     signed/unsigned warnings.
2330    
2331     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2332     option for pcretest, so I've replaced it by a simple function that does just
2333     that job.
2334    
2335     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2336     "pcregrep -".
2337    
2338     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2339     Java package. This provides some syntactic sugar for simple cases of what my
2340     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2341     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2342     item, you can use this simplified notation. Note that only makes sense with
2343     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2344     greediness, whatever the setting of the PCRE_UNGREEDY option.
2345    
2346     13. A change of greediness default within a pattern was not taking effect at
2347     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2348     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2349     was abstracted outside.
2350    
2351     14. PCRE now supports the \G assertion. It is true when the current matching
2352     position is at the start point of the match. This differs from \A when the
2353     starting offset is non-zero. Used with the /g option of pcretest (or similar
2354     code), it works in the same way as it does for Perl's /g option. If all
2355     alternatives of a regex begin with \G, the expression is anchored to the start
2356     match position, and the "anchored" flag is set in the compiled expression.
2357    
2358     15. Some bugs concerning the handling of certain option changes within patterns
2359     have been fixed. These applied to options other than (?ims). For example,
2360     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2361     been the other way round. Some of this was related to change 7 above.
2362    
2363     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2364     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2365     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2366     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2367    
2368     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2369     mode. Unlike ".", it always matches newline, whatever the setting of
2370     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2371     assertions. Perl allows it, but it doesn't (in general) work because it can't
2372     calculate the length of the lookbehind. At least, that's the case for Perl
2373     5.8.0 - I've been told they are going to document that it doesn't work in
2374     future.
2375    
2376     18. Added an error diagnosis for escapes that PCRE does not support: these are
2377     \L, \l, \N, \P, \p, \U, \u, and \X.
2378    
2379     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2380     reading past the end of the pattern in cases such as /[abcd/.
2381    
2382     20. PCRE was getting more memory than necessary for patterns with classes that
2383     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2384    
2385     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2386     compiling PCRE for use with Virtual Pascal.
2387    
2388     22. Small fix to the Makefile to make it work properly if the build is done
2389     outside the source tree.
2390    
2391     23. Added a new extension: a condition to go with recursion. If a conditional
2392     subpattern starts with (?(R) the "true" branch is used if recursion has
2393     happened, whereas the "false" branch is used only at the top level.
2394    
2395     24. When there was a very long string of literal characters (over 255 bytes
2396     without UTF support, over 250 bytes with UTF support), the computation of how
2397     much memory was required could be incorrect, leading to segfaults or other
2398     strange effects.
2399    
2400     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2401     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2402     there was a subsequent back reference to those brackets. This meant that, for
2403     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2404     possible to check for precisely this case. All we can do is abandon the
2405     optimization if .* occurs inside capturing brackets when there are any back
2406     references whatsoever. (See below for a better fix that came later.)
2407    
2408     26. The handling of the optimization for finding the first character of a
2409     non-anchored pattern, and for finding a character that is required later in the
2410     match were failing in some cases. This didn't break the matching; it just
2411     failed to optimize when it could. The way this is done has been re-implemented.
2412    
2413     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2414    
2415     28. Added a new feature that provides some of the functionality that Perl
2416     provides with (?{...}). The facility is termed a "callout". The way it is done
2417     in PCRE is for the caller to provide an optional function, by setting
2418     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2419     global variable. By default it is unset, which disables all calling out. To get
2420     the function called, the regex must include (?C) at appropriate points. This
2421     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2422     This provides a means of identifying different callout points. When PCRE
2423     reaches such a point in the regex, if pcre_callout has been set, the external
2424     function is called. It is provided with data in a structure called
2425     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2426     matching continues; if it returns a non-zero value, the match at the current
2427     point fails. However, backtracking will occur if possible. [This was changed
2428     later and other features added - see item 49 below.]
2429    
2430     29. pcretest is upgraded to test the callout functionality. It provides a
2431     callout function that displays information. By default, it shows the start of
2432     the match and the current position in the text. There are some new data escapes
2433     to vary what happens:
2434    
2435     \C+ in addition, show current contents of captured substrings
2436     \C- do not supply a callout function
2437     \C!n return 1 when callout number n is reached
2438     \C!n!m return 1 when callout number n is reached for the mth time
2439    
2440     30. If pcregrep was called with the -l option and just a single file name, it
2441     output "<stdin>" if a match was found, instead of the file name.
2442    
2443     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2444     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2445     pcre_exec(). This saves a malloc/free per call. The default value of
2446     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2447     when configuring.
2448    
2449     32. The default maximum size of a compiled pattern is 64K. There have been a
2450     few cases of people hitting this limit. The code now uses macros to handle the
2451     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2452     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2453     configuring. Tests 2 and 5 work only with 2-byte links because they output
2454     debugging information about compiled patterns.
2455    
2456     33. Internal code re-arrangements:
2457    
2458     (a) Moved the debugging function for printing out a compiled regex into
2459     its own source file (printint.c) and used #include to pull it into
2460     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2461     separate copies.
2462    
2463     (b) Defined the list of op-code names for debugging as a macro in
2464     internal.h so that it is next to the definition of the opcodes.
2465    
2466     (c) Defined a table of op-code lengths for simpler skipping along compiled
2467     code. This is again a macro in internal.h so that it is next to the
2468     definition of the opcodes.
2469    
2470     34. Added support for recursive calls to individual subpatterns, along the
2471     lines of Robin Houston's patch (but implemented somewhat differently).
2472    
2473     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2474     allow it to read and process whole directories in Win32. This code was
2475     contributed by Lionel Fourquaux; it has not been tested by me.
2476    
2477     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2478     used to name a group. Names consist of alphanumerics and underscores, and must
2479     be unique. Back references use the syntax (?P=name) and recursive calls use
2480     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2481     numbers. The function pcre_fullinfo() can be used after compilation to extract
2482     a name/number map. There are three relevant calls:
2483    
2484     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2485     PCRE_INFO_NAMECOUNT yields the number of entries
2486     PCRE_INFO_NAMETABLE yields a pointer to the map.
2487    
2488     The map is a vector of fixed-size entries. The size of each entry depends on
2489     the length of the longest name used. The first two bytes of each entry are the
2490     group number, most significant byte first. There follows the corresponding
2491     name, zero terminated. The names are in alphabetical order.
2492    
2493     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2494     case instead of 255. Making it the same both with and without UTF-8 support
2495     means that the same test output works with both.
2496    
2497     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2498     calling malloc() with a zero argument.
2499    
2500     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2501     optimization. I've improved things by keeping a bitmap of backreferences with
2502     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2503     fact referenced, the optimization can be applied. It is unlikely that a
2504     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2505     the match to follow \n) will appear inside brackets with a number greater than
2506     31, but if it does, any back reference > 31 suppresses the optimization.
2507    
2508     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2509     of disabling numbered capturing parentheses. Any opening parenthesis that is
2510     not followed by ? behaves as if it were followed by ?: but named parentheses
2511     can still be used for capturing (and they will acquire numbers in the usual
2512     way).
2513    
2514     41. Redesigned the return codes from the match() function into yes/no/error so
2515     that errors can be passed back from deep inside the nested calls. A malloc
2516     failure while inside a recursive subpattern call now causes the
2517     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2518    
2519     42. It is now possible to set a limit on the number of times the match()
2520     function is called in a call to pcre_exec(). This facility makes it possible to
2521     limit the amount of recursion and backtracking, though not in a directly
2522     obvious way, because the match() function is used in a number of different
2523     circumstances. The count starts from zero for each position in the subject
2524     string (for non-anchored patterns). The default limit is, for compatibility, a
2525     large number, namely 10 000 000. You can change this in two ways:
2526    
2527     (a) When configuring PCRE before making, you can use --with-match-limit=n
2528     to set a default value for the compiled library.
2529    
2530     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2531     a different value is set. See 45 below.
2532    
2533     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2534    
2535     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2536     of things that can be changed at compile time. The first argument specifies
2537     what is wanted and the second points to where the information is to be placed.
2538     The current list of available information is:
2539    
2540     PCRE_CONFIG_UTF8
2541    
2542     The output is an integer that is set to one if UTF-8 support is available;
2543     otherwise it is set to zero.
2544    
2545     PCRE_CONFIG_NEWLINE
2546    
2547     The output is an integer that it set to the value of the code that is used for
2548     newline. It is either LF (10) or CR (13).
2549    
2550     PCRE_CONFIG_LINK_SIZE
2551    
2552     The output is an integer that contains the number of bytes used for internal
2553     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2554    
2555     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2556    
2557     The output is an integer that contains the threshold above which the POSIX
2558     interface uses malloc() for output vectors. See item 31 above.
2559    
2560     PCRE_CONFIG_MATCH_LIMIT
2561    
2562     The output is an unsigned integer that contains the default limit of the number
2563     of match() calls in a pcre_exec() execution. See 42 above.
2564    
2565     44. pcretest has been upgraded by the addition of the -C option. This causes it
2566     to extract all the available output from the new pcre_config() function, and to
2567     output it. The program then exits immediately.
2568    
2569     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2570     order to support additional features. One way would have been to define
2571     pcre_exec2() (for example) with extra arguments, but this would not have been
2572     extensible, and would also have required all calls to the original function to
2573     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2574     is used for passing in "extra" data from pcre_study().
2575    
2576     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2577     contains the following fields:
2578    
2579     flags a bitmap indicating which of the following fields are set
2580     study_data opaque data from pcre_study()
2581     match_limit a way of specifying a limit on match() calls for a specific
2582     call to pcre_exec()
2583     callout_data data for callouts (see 49 below)
2584    
2585     The flag bits are also defined in pcre.h, and are
2586    
2587     PCRE_EXTRA_STUDY_DATA
2588     PCRE_EXTRA_MATCH_LIMIT
2589     PCRE_EXTRA_CALLOUT_DATA
2590    
2591     The pcre_study() function now returns one of these new pcre_extra blocks, with
2592     the actual study data pointed to by the study_data field, and the
2593     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2594     before. That is, this change is entirely upwards-compatible and requires no
2595     change to existing code.
2596    
2597     If you want to pass in additional data to pcre_exec(), you can either place it
2598     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2599     block.
2600    
2601     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2602     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2603     times with different match limits, until it finds the minimum value needed for
2604     pcre_exec() to complete. The value is then output. This can be instructive; for
2605     most simple matches the number is quite small, but for pathological cases it
2606     gets very large very quickly.
2607    
2608     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2609     returns the size of the data block pointed to by the study_data field in a
2610     pcre_extra block, that is, the value that was passed as the argument to
2611     pcre_malloc() when PCRE was getting memory in which to place the information
2612     created by pcre_study(). The fourth argument should point to a size_t variable.
2613     pcretest has been extended so that this information is shown after a successful
2614     pcre_study() call when information about the compiled regex is being displayed.
2615    
2616     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2617     because what follows is always an absolute path. (Later: it turns out that this
2618     is more than cosmetic for MinGW, because it doesn't like empty path
2619     components.)
2620    
2621     49. Some changes have been made to the callout feature (see 28 above):
2622    
2623     (i) A callout function now has three choices for what it returns:
2624    
2625     0 => success, carry on matching
2626     > 0 => failure at this point, but backtrack if possible
2627     < 0 => serious error, return this value from pcre_exec()
2628    
2629     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2630     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2631     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2632     use by callout functions. It will never be used by PCRE itself.
2633    
2634     (ii) The pcre_extra structure (see 45 above) has a void * field called
2635     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2636     pcre_callout_block structure has a field of the same name. The contents of
2637     the field passed in the pcre_extra structure are passed to the callout
2638     function in the corresponding field in the callout block. This makes it
2639     easier to use the same callout-containing regex from multiple threads. For
2640     testing, the pcretest program has a new data escape
2641    
2642     \C*n pass the number n (may be negative) as callout_data
2643    
2644     If the callout function in pcretest receives a non-zero value as
2645     callout_data, it returns that value.
2646    
2647     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2648     there were some redundant $(CFLAGS) in commands that are now specified as
2649     $(LINK), which already includes $(CFLAGS).
2650    
2651     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2652     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2653     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2654     one-byte characters throughout. Note that case-insensitive matching applies
2655     only to characters whose values are less than 256. PCRE doesn't support the
2656     notion of cases for higher-valued characters.
2657    
2658     (i) A character class whose characters are all within 0-255 is handled as
2659     a bit map, and the map is inverted for negative classes. Previously, a
2660     character > 255 always failed to match such a class; however it should
2661     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2662    
2663     (ii) A negated character class with a single character < 255 is coded as
2664     "not this character" (OP_NOT). This wasn't working properly when the test
2665     character was multibyte, either singly or repeated.
2666    
2667     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2668     mode, for example: \x{100}{2,3}.
2669    
2670     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2671     singly or repeated) now correctly test multibyte characters. However,
2672     PCRE doesn't recognize any characters with values greater than 255 as
2673     digits, spaces, or word characters. Such characters always match \D, \S,
2674     and \W, and never match \d, \s, or \w.
2675    
2676     (v) Classes may now contain characters and character ranges with values
2677     greater than 255. For example: [ab\x{100}-\x{400}].
2678    
2679     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2680     PCRE in UTF-8 mode.
2681    
2682     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2683     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2684     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2685     value.)
2686    
2687     53. The single man page has become too large. I have therefore split it up into
2688     a number of separate man pages. These also give rise to individual HTML pages;
2689     these are now put in a separate directory, and there is an index.html page that
2690     lists them all. Some hyperlinking between the pages has been installed.
2691    
2692     54. Added convenience functions for handling named capturing parentheses.
2693    
2694     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2695     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2696     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2697     are faulted.
2698    
2699     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2700     calling configure. These values are used when compiling the dftables.c program
2701     which is run to generate the source of the default character tables. They
2702     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2703     you will need to set these values.
2704    
2705     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2706    
2707    
2708     Version 3.9 02-Jan-02
2709 nigel 61 ---------------------
2710    
2711     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2712    
2713     2. If --disable-static was given, the building process failed when trying to
2714     build pcretest and pcregrep. (For some reason it was using libtool to compile
2715     them, which is not right, as they aren't part of the library.)
2716    
2717    
2718 nigel 59 Version 3.8 18-Dec-01
2719     ---------------------
2720    
2721     1. The experimental UTF-8 code was completely screwed up. It was packing the
2722     bytes in the wrong order. How dumb can you get?
2723    
2724    
2725 nigel 57 Version 3.7 29-Oct-01
2726     ---------------------
2727    
2728     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2729     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2730     this didn't happen under Solaris 8, where I normally test things.
2731    
2732 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2733     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2734     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2735     this fix an hour or so after the initial 3.7 release.)
2736 nigel 57
2737 nigel 59
2738 nigel 55 Version 3.6 23-Oct-01
2739     ---------------------
2740    
2741     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2742     offsets passed as NULL with zero offset count.
2743    
2744     2. The config.guess and config.sub files had not been updated when I moved to
2745     the latest autoconf.
2746    
2747    
2748 nigel 53 Version 3.5 15-Aug-01
2749     ---------------------
2750 nigel 5
2751 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2752     had been forgotten.
2753    
2754     2. By using declared but undefined structures, we can avoid using "void"
2755     definitions in pcre.h while keeping the internal definitions of the structures
2756     private.
2757    
2758     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2759     user point of view, this means that both static and shared libraries are built
2760     by default, but this can be individually controlled. More of the work of
2761     handling this static/shared cases is now inside libtool instead of PCRE's make
2762     file.
2763    
2764     4. The pcretest utility is now installed along with pcregrep because it is
2765     useful for users (to test regexs) and by doing this, it automatically gets
2766     relinked by libtool. The documentation has been turned into a man page, so
2767     there are now .1, .txt, and .html versions in /doc.
2768    
2769     5. Upgrades to pcregrep:
2770     (i) Added long-form option names like gnu grep.
2771     (ii) Added --help to list all options with an explanatory phrase.
2772     (iii) Added -r, --recursive to recurse into sub-directories.
2773     (iv) Added -f, --file to read patterns from a file.
2774    
2775     6. pcre_exec() was referring to its "code" argument before testing that
2776     argument for NULL (and giving an error if it was NULL).
2777    
2778     7. Upgraded Makefile.in to allow for compiling in a different directory from
2779     the source directory.
2780    
2781     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2782     options bits, the pointer it was passed was to an int instead of to an unsigned
2783     long int. This mattered only on 64-bit systems.
2784    
2785     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2786     generated) instead of pcre.in, which it its source. Also made the same change
2787     in several of the .c files.
2788    
2789     10. A new release of gcc defines printf() as a macro, which broke pcretest
2790     because it had an ifdef in the middle of a string argument for printf(). Fixed
2791     by using separate calls to printf().
2792    
2793     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2794     script, to force use of CR or LF instead of \n in the source. On non-Unix
2795     systems, the value can be set in config.h.
2796    
2797     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2798     absolute limit. Changed the text of the error message to make this clear, and
2799     likewise updated the man page.
2800    
2801     13. The limit of 99 on the number of capturing subpatterns has been removed.
2802     The new limit is 65535, which I hope will not be a "real" limit.
2803    
2804    
2805 nigel 51 Version 3.4 22-Aug-00
2806     ---------------------
2807    
2808     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2809    
2810     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2811    
2812    
2813 nigel 49 Version 3.3 01-Aug-00
2814     ---------------------
2815    
2816     1. If an octal character was given, but the value was greater than \377, it
2817     was not getting masked to the least significant bits, as documented. This could
2818     lead to crashes in some systems.
2819    
2820     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2821     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2822    
2823     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2824     These just pass their arguments on to (pcre_free)(), but they are provided
2825     because some uses of PCRE bind it to non-C systems that can call its functions,
2826     but cannot call free() or pcre_free() directly.
2827    
2828     4. Add "make test" as a synonym for "make check". Corrected some comments in
2829     the Makefile.
2830    
2831     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2832     Makefile.
2833    
2834     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2835     command called pgrep for grepping around the active processes.
2836    
2837     7. Added the beginnings of support for UTF-8 character strings.
2838    
2839     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2840     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2841     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2842     out for the ar command.)
2843    
2844    
2845 nigel 47 Version 3.2 12-May-00
2846     ---------------------
2847    
2848     This is purely a bug fixing release.
2849    
2850     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2851     of ZA. This was just one example of several cases that could provoke this bug,
2852     which was introduced by change 9 of version 2.00. The code for breaking
2853     infinite loops after an iteration that matches an empty string was't working
2854     correctly.
2855    
2856     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2857     when matched against abbab (for example). After matching an empty string, it
2858     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2859     caused it to match further down the string than it should.
2860    
2861     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2862     was there because it doesn't seem to be needed, and it causes trouble on some
2863     systems, as it is not a Standard C header. It has been removed.
2864    
2865     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2866     were reported on the Macintosh. The changes were from
2867    
2868     while ((c = *(++ptr)) != 0 && c != '\n');
2869     to
2870     while ((c = *(++ptr)) != 0 && c != '\n') ;
2871    
2872     Totally extraordinary, but if that's what it takes...
2873    
2874     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2875     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2876     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2877     assumes the way PCRE uses memmove() (always moving upwards).
2878    
2879     6. PCRE is being used in one environment where strchr() is not available. There
2880     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2881     faster code anyway.
2882    
2883    
2884 nigel 45 Version 3.1 09-Feb-00
2885     ---------------------
2886    
2887     The only change in this release is the fixing of some bugs in Makefile.in for
2888     the "install" target:
2889    
2890     (1) It was failing to install pcreposix.h.
2891    
2892     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2893    
2894    
2895 nigel 43 Version 3.0 01-Feb-00
2896     ---------------------
2897 nigel 41
2898     1. Add support for the /+ modifier to perltest (to output $` like it does in
2899     pcretest).
2900    
2901     2. Add support for the /g modifier to perltest.
2902    
2903     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2904     matches null strings.
2905    
2906     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2907     pattern. Perl treats empty patterns specially - it reuses the most recent
2908     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2909     effect.
2910    
2911     5. The POSIX interface was broken in that it was just handing over the POSIX
2912     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2913     required a bigger vector, with some working space on the end. This means that
2914     the POSIX wrapper now has to get and free some memory, and copy the results.
2915    
2916 nigel 43 6. Added some simple autoconf support, placing the test data and the
2917     documentation in separate directories, re-organizing some of the
2918     information files, and making it build pcre-config (a GNU standard). Also added
2919     libtool support for building PCRE as a shared library, which is now the
2920     default.
2921 nigel 41
2922 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2923     09 are not valid octal constants. Single digits will be used for minor values
2924     less than 10.
2925    
2926     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2927     existing programs that set these in the POSIX interface can use PCRE without
2928     modification.
2929    
2930     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2931     return all that pcre_info() returns, plus additional data. The pcre_info()
2932     function is retained for compatibility, but is considered to be obsolete.
2933    
2934     10. Added experimental recursion feature (?R) to handle one common case that
2935     Perl 5.6 will be able to do with (?p{...}).
2936    
2937     11. Added support for POSIX character classes like [:alpha:], which Perl is
2938     adopting.
2939    
2940    
2941 nigel 39 Version 2.08 31-Aug-99
2942     ----------------------
2943    
2944     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2945     trying to match at the startoffset position, but instead was moving forward to
2946     the next newline as if a previous match had failed.
2947    
2948     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2949     and could get into a loop if a null string was matched other than at the start
2950     of the subject.
2951    
2952     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2953     be distinguished at compile time, and for completeness also added PCRE_DATE.
2954    
2955     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2956     in GnuWin32 environments.
2957    
2958    
2959 nigel 37 Version 2.07 29-Jul-99
2960     ----------------------
2961    
2962     1. The documentation is now supplied in plain text form and HTML as well as in
2963     the form of man page sources.
2964    
2965     2. C++ compilers don't like assigning (void *) values to other pointer types.
2966     In particular this affects malloc(). Although there is no problem in Standard
2967     C, I've put in casts to keep C++ compilers happy.
2968    
2969     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2970     should be (const char *).
2971    
2972     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2973     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2974     However, I haven't made this a standard facility. The documentation doesn't
2975     mention it, and the Makefile doesn't support it.
2976    
2977     5. The Makefile now contains an "install" target, with editable destinations at
2978     the top of the file. The pcretest program is not installed.
2979    
2980     6. pgrep -V now gives the PCRE version number and date.
2981    
2982     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2983     causing the entire string to be ignored, instead of just the last character.
2984    
2985     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2986     non-matching string, it can take a very, very long time, even for strings of
2987     quite modest length, because of the nested recursion. PCRE now does better in
2988     some of these cases. It does this by remembering the last required literal
2989     character in the pattern, and pre-searching the subject to ensure it is present
2990     before running the real match. In other words, it applies a heuristic to detect
2991     some types of certain failure quickly, and in the above example, if presented
2992     with a string that has no trailing " it gives "no match" very quickly.
2993    
2994     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2995     other alternatives are tried instead.
2996    
2997    
2998 nigel 35 Version 2.06 09-Jun-99
2999     ----------------------
3000    
3001     1. Change pcretest's output for amount of store used to show just the code
3002     space, because the remainder (the data block) varies in size between 32-bit and
3003     64-bit systems.
3004    
3005     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3006     start matching at. This allows lookbehinds to work when searching for multiple
3007     occurrences in a string.
3008    
3009     3. Added additional options to pcretest for testing multiple occurrences:
3010    
3011     /+ outputs the rest of the string that follows a match
3012     /g loops for multiple occurrences, using the new startoffset argument
3013     /G loops for multiple occurrences by passing an incremented pointer
3014    
3015     4. PCRE wasn't doing the "first character" optimization for patterns starting
3016     with \b or \B, though it was doing it for other lookbehind assertions. That is,
3017     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3018     the letter 'x'. On long subject strings, this gives a significant speed-up.
3019    
3020    
3021 nigel 33 Version 2.05 21-Apr-99
3022     ----------------------
3023    
3024     1. Changed the type of magic_number from int to long int so that it works
3025     properly on 16-bit systems.
3026    
3027     2. Fixed a bug which caused patterns starting with .* not to work correctly
3028     when the subject string contained newline characters. PCRE was assuming
3029     anchoring for such patterns in all cases, which is not correct because .* will
3030     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3031     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3032     must be retried after every newline in the subject.
3033    
3034    
3035 nigel 31 Version 2.04 18-Feb-99
3036     ----------------------
3037    
3038     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3039     computation of the store needed to hold the pattern was incorrect (too large).
3040     If such patterns were nested a few deep, this could multiply and become a real
3041     problem.
3042    
3043     2. Added /M option to pcretest to show the memory requirement of a specific
3044     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3045    
3046     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3047     compiled in such a way that the backtracking after subsequent failure was
3048     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3049     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3050    
3051    
3052 nigel 29 Version 2.03 02-Feb-99
3053     ----------------------
3054    
3055     1. Fixed typo and small mistake in man page.
3056    
3057 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3058     LICENCE file containing the conditions.
3059 nigel 29
3060     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3061     Perl, that is the internal \ allows the delimiter to be included in the
3062     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3063     the final delimiter, add \ to the end of the pattern (to test the error).
3064    
3065     4. Added the convenience functions for extracting substrings after a successful
3066     match. Updated pcretest to make it able to test these functions.
3067    
3068    
3069 nigel 27 Version 2.02 14-Jan-99
3070     ----------------------
3071    
3072     1. Initialized the working variables associated with each extraction so that
3073     their saving and restoring doesn't refer to uninitialized store.
3074    
3075     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3076     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3077     fix the problem.
3078    
3079     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3080     calls, and wasn't printing the correct value for compiling calls. Increased the
3081     default value of LOOPREPEAT, and the number of significant figures in the
3082     times.
3083    
3084     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3085    
3086     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3087     a building problem on Windows NT with a FAT file system.
3088    
3089    
3090 nigel 25 Version 2.01 21-Oct-98
3091     ----------------------
3092    
3093     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3094     to character tables built by pcre_maketables() in the current locale. If NULL
3095     is passed, the default tables are used.
3096    
3097    
3098 nigel 23 Version 2.00 24-Sep-98
3099 nigel 21 ----------------------
3100    
3101 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3102     it any more.
3103    
3104     2. Allow quantification of (?>) groups, and make it work correctly.
3105    
3106     3. The first character computation wasn't working for (?>) groups.
3107    
3108     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3109     end of the subject) and add 5.005's \z, which really does match only at the
3110     very end of the subject.
3111    
3112     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3113    
3114     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3115     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3116     localized options. All options to pcre_study() were also removed.
3117    
3118     7. Add other new features from 5.005:
3119    
3120     $(?<= positive lookbehind
3121     $(?<! negative lookbehind
3122     (?imsx-imsx) added the unsetting capability
3123     such a setting is global if at outer level; local otherwise
3124     (?imsx-imsx:) non-capturing groups with option setting
3125     (?(cond)re|re) conditional pattern matching
3126    
3127     A backreference to itself in a repeated group matches the previous
3128     captured string.
3129    
3130     8. General tidying up of studying (both automatic and via "study")
3131     consequential on the addition of new assertions.
3132    
3133     9. As in 5.005, unlimited repeated groups that could match an empty substring
3134     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3135     runtime if any iteration does actually match an empty substring.
3136    
3137     10. Include the RunTest script in the distribution.
3138    
3139     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3140     discrepancies, some of which were old and were also with respect to 5.004. They
3141     have now been fixed.
3142    
3143    
3144     Version 1.09 28-Apr-98
3145     ----------------------
3146    
3147 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3148     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3149     program crashes, or just wrong answers. This did not apply to negated classes
3150     containing more than one character, or to minima other than one.
3151    
3152    
3153 nigel 19 Version 1.08 27-Mar-98
3154     ----------------------
3155    
3156     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3157    
3158     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3159     latter must appear before anything that relies on it in the pattern.
3160    
3161    
3162 nigel 17 Version 1.07 16-Feb-98
3163     ----------------------
3164    
3165     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3166     repeat of a potentially empty string).
3167    
3168    
3169 nigel 15 Version 1.06 23-Jan-98
3170     ----------------------
3171    
3172     1. Added Markus Oberhumer's little patches for C++.
3173    
3174     2. Literal strings longer than 255 characters were broken.
3175    
3176    
3177 nigel 13 Version 1.05 23-Dec-97
3178     ----------------------
3179    
3180     1. Negated character classes containing more than one character were failing if
3181     PCRE_CASELESS was set at run time.
3182    
3183    
3184 nigel 11 Version 1.04 19-Dec-97
3185     ----------------------
3186    
3187     1. Corrected the man page, where some "const" qualifiers had been omitted.
3188    
3189     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3190     input syntax.
3191    
3192     3. Fixed memory leak which occurred when a regex with back references was
3193     matched with an offsets vector that wasn't big enough. The temporary memory
3194     that is used in this case wasn't being freed if the match failed.
3195    
3196     4. Tidied pcretest to ensure it frees memory that it gets.
3197    
3198     5. Temporary memory was being obtained in the case where the passed offsets
3199     vector was exactly big enough.
3200    
3201     6. Corrected definition of offsetof() from change 5 below.
3202    
3203     7. I had screwed up change 6 below and broken the rules for the use of
3204     setjmp(). Now fixed.
3205    
3206    
3207 nigel 9 Version 1.03 18-Dec-97
3208     ----------------------
3209    
3210     1. A erroneous regex with a missing opening parenthesis was correctly
3211     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3212     on some systems.
3213    
3214     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3215     it was reported that one broken compiler failed on the former because "code" is
3216     also an independent variable.
3217    
3218     3. The erroneous regex a[]b caused an array overrun reference.
3219    
3220     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3221     fail on data ending with that character. (It was going on too far, and checking
3222     the next character, typically a binary zero.) This was specific to the
3223     optimized code for single-character negative classes.
3224    
3225     5. Added a contributed patch from the TIN world which does the following:
3226    
3227     + Add an undef for memmove, in case the the system defines a macro for it.
3228    
3229     + Add a definition of offsetof(), in case there isn't one. (I don't know
3230     the reason behind this - offsetof() is part of the ANSI standard - but
3231     it does no harm).
3232    
3233     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3234     most of the places where whitespace preceded '#'. I have given up and
3235     allowed the remaining 2 cases to be at the margin.
3236    
3237     + Rename some variables in pcre to eliminate shadowing. This seems very
3238     pedantic, but does no harm, of course.
3239    
3240     6. Moved the call to setjmp() into its own function, to get rid of warnings
3241     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3242    
3243     7. Constructs such as \d{8,} were compiling into the equivalent of
3244 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3245 nigel 9 outcome, but in this particular case used more store than had been allocated,
3246     which caused the bug to be discovered because it threw up an internal error.
3247    
3248     8. The debugging code in both pcre and pcretest for outputting the compiled
3249     form of a regex was going wrong in the case of back references followed by
3250     curly-bracketed repeats.
3251    
3252    
3253 nigel 7 Version 1.02 12-Dec-97
3254     ----------------------
3255    
3256     1. Typos in pcre.3 and comments in the source fixed.
3257    
3258     2. Applied a contributed patch to get rid of places where it used to remove
3259     'const' from variables, and fixed some signed/unsigned and uninitialized
3260     variable warnings.
3261    
3262     3. Added the "runtest" target to Makefile.
3263    
3264     4. Set default compiler flag to -O2 rather than just -O.
3265    
3266    
3267 nigel 5 Version 1.01 19-Nov-97
3268     ----------------------
3269    
3270     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3271     like /([ab]*)*/, that is, for classes with more than one character in them.
3272    
3273     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3274     as /((?>a*))*/ (a PCRE_EXTRA facility).
3275    
3276    
3277     Version 1.00 18-Nov-97
3278     ----------------------
3279    
3280     1. Added compile-time macros to support systems such as SunOS4 which don't have
3281     memmove() or strerror() but have other things that can be used instead.
3282    
3283     2. Arranged that "make clean" removes the executables.
3284    
3285    
3286 nigel 3 Version 0.99 27-Oct-97
3287     ----------------------
3288    
3289     1. Fixed bug in code for optimizing classes with only one character. It was
3290     initializing a 32-byte map regardless, which could cause it to run off the end
3291     of the memory it had got.
3292    
3293     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3294    
3295    
3296     Version 0.98 22-Oct-97
3297     ----------------------
3298    
3299     1. Fixed bug in code for handling temporary memory usage when there are more
3300     back references than supplied space in the ovector. This could cause segfaults.
3301    
3302    
3303     Version 0.97 21-Oct-97
3304     ----------------------
3305    
3306     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3307    
3308     2. Optimized negated single characters not to use a bit map.
3309    
3310     3. Brought error texts together as macro definitions; clarified some of them;
3311     fixed one that was wrong - it said "range out of order" when it meant "invalid
3312     escape sequence".
3313    
3314     4. Changed some char * arguments to const char *.
3315    
3316     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3317    
3318     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3319     pcretest.
3320    
3321    
3322     Version 0.96 16-Oct-97
3323     ----------------------
3324    
3325     1. Added a simple "pgrep" utility to the distribution.
3326    
3327     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3328     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3329     where "ddd" means "one or more decimal digits".
3330    
3331     3. Fixed serious bug. If a pattern had a back reference, but the call to
3332     pcre_exec() didn't supply a large enough ovector to record the related
3333     identifying subpattern, the match always failed. PCRE now remembers the number
3334     of the largest back reference, and gets some temporary memory in which to save
3335     the offsets during matching if necessary, in order to ensure that
3336     backreferences always work.
3337    
3338     4. Increased the compatibility with Perl in a number of ways:
3339    
3340     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3341     to request this handling. The option can be set at compile or exec time.
3342    
3343     (b) $ matches before a terminating newline by default; an option
3344     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3345     mode). The option can be set at compile or exec time.
3346    
3347     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3348     the same as Perl's. If the decimal number it represents is less than 10
3349     or there aren't that many previous left capturing parentheses, an octal
3350     escape is read. Inside a character class, it's always an octal escape,
3351     even if it is a single digit.
3352    
3353     (d) An escaped but undefined alphabetic character is taken as a literal,
3354     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3355     escapes.
3356    
3357     (e) {0} is now permitted. (The previous item is removed from the compiled
3358     pattern).
3359    
3360     5. Changed all the names of code files so that the basic parts are no longer
3361     than 10 characters, and abolished the teeny "globals.c" file.
3362    
3363     6. Changed the handling of character classes; they are now done with a 32-byte
3364     bit map always.
3365    
3366     7. Added the -d and /D options to pcretest to make it possible to look at the
3367     internals of compilation without having to recompile pcre.
3368    
3369    
3370     Version 0.95 23-Sep-97
3371     ----------------------
3372    
3373     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3374     \x20 at the start of a run of normal characters. These were being treated as
3375     real characters, instead of the source characters being re-checked.
3376    
3377    
3378     Version 0.94 18-Sep-97
3379     ----------------------
3380    
3381     1. The functions are now thread-safe, with the caveat that the global variables
3382     containing pointers to malloc() and free() or alternative functions are the
3383     same for all threads.
3384    
3385     2. Get pcre_study() to generate a bitmap of initial characters for non-
3386     anchored patterns when this is possible, and use it if passed to pcre_exec().
3387    
3388    
3389     Version 0.93 15-Sep-97
3390     ----------------------
3391    
3392     1. /(b)|(:+)/ was computing an incorrect first character.
3393    
3394     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3395     but not actually doing anything yet.
3396    
3397     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3398     as Perl does (e.g. [-az] or [az-]).
3399    
3400     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3401     all possible positions.
3402    
3403     5. Split up into different modules to avoid including unneeded functions in a
3404     compiled binary. However, compile and exec are still in one module. The "study"
3405     function is split off.
3406    
3407     6. The character tables are now in a separate module whose source is generated
3408     by an auxiliary program - but can then be edited by hand if required. There are
3409     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3410     toupper() in the code.
3411    
3412     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3413     make them global. Abolish the function for setting them, as the caller can now
3414     set them directly.
3415    
3416    
3417     Version 0.92 11-Sep-97
3418     ----------------------
3419    
3420     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3421     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3422    
3423     2. Caseless matching was not working in character classes if the characters in
3424     the pattern were in upper case.
3425    
3426     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3427    
3428     4. Make PCRE_ANCHORED public and accept as a compile option.
3429    
3430     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3431     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3432     pass them.
3433    
3434     6. Give an error if bad option bits passed at compile or run time.
3435    
3436     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3437     pcretest to cause it to pass that flag.
3438    
3439     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3440     options, and the first character, if set.
3441    
3442     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3443    
3444    
3445     Version 0.91 10-Sep-97
3446     ----------------------
3447    
3448     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3449     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3450    
3451     2. PCRE was looping on encountering an indefinitely repeated back reference to
3452     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3453     Perl does - treats the match as successful.
3454    
3455     ****

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