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Wed Jul 9 11:03:07 2008 UTC (6 years, 9 months ago) by ph10
File size: 157645 byte(s)
Comments about stack usage added.

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


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