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Revision 326 - (hide annotations) (download)
Sat Mar 8 17:24:02 2008 UTC (7 years, 1 month ago) by ph10
File size: 152323 byte(s)
Craig's patch to the QuoteMeta function in pcrecpp.cc so that it escapes the
NUL character as backslash + 0 rather than backslash + NUL, because PCRE
doesn't support NULs in patterns.

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


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