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Revision 226 - (hide annotations) (download)
Tue Aug 21 11:46:08 2007 UTC (7 years, 8 months ago) by ph10
File size: 138505 byte(s)
Don't advance by 2 if explicit \r or \n in the pattern. Add 

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 223 Version 7.3 20-Aug-07
5 ph10 157 ---------------------
7 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
8     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9     brackets there is not right, since it causes compilers to look for an
10     installed pcre.h, not the version that is in the source that is being
11     compiled (which of course may be different). I have changed it back to:
12 ph10 197
13 ph10 189 #include "pcre.h"
14 ph10 197
15     I have a vague recollection that the change was concerned with compiling in
16     different directories, but in the new build system, that is taken care of
17     by the VPATH setting the Makefile.
19 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20     when the subject happened to end in the byte 0x85 (e.g. if the last
21     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22     characters but of course it shouldn't be taken as a newline when it is part
23     of another character. The bug was that, for an unlimited repeat of . in
24     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25     characters when looking for a newline.
26 ph10 197
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30     in debug output.
32 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33     long printing in the pcrecpp unittest when running under MinGW.
34 ph10 189
35 ph10 197 6. ESC_K was left out of the EBCDIC table.
36 ph10 189
37 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39     limit also applies to "virtual nesting" when a pattern is recursive, and in
40     this case 1000 isn't so big. I have been able to remove this limit at the
41     expense of backing off one optimization in certain circumstances. Normally,
42     when pcre_exec() would call its internal match() function recursively and
43     immediately return the result unconditionally, it uses a "tail recursion"
44     feature to save stack. However, when a subpattern that can match an empty
45     string has an unlimited repetition quantifier, it no longer makes this
46     optimization. That gives it a stack frame in which to save the data for
47     checking that an empty string has been matched. Previously this was taken
48     from the 1000-entry workspace that had been reserved. So now there is no
49     explicit limit, but more stack is used.
50 ph10 189
51 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
52     syntax that is required for Windows, and which was going wrong for the
53     pcreposix and pcrecpp parts of the library. These were overlooked when this
54     problem was solved for the main library.
55 ph10 197
56 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
57     the size of patterns that contain repeated groups with explicit upper
58     limits. As the maximum quantifier is 65535, the maximum group length was
59     set at 30,000 so that the product of these two numbers did not overflow a
60     32-bit integer. However, it turns out that people want to use groups that
61     are longer than 30,000 bytes (though not repeat them that many times).
62     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63     made it possible to implement the integer overflow checks in a much more
64     dynamic way, which I have now done. The artificial limitation on group
65     length has been removed - we now have only the limit on the total length of
66     the compiled pattern, which depends on the LINK_SIZE setting.
67 ph10 208
68     10. Fixed a bug in the documentation for get/copy named substring when
69     duplicate names are permitted. If none of the named substrings are set, the
70     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71     empty string.
73     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75     because the ] is interpreted as the first data character and the
76     terminating ] is not found. PCRE has been made compatible with Perl in this
77     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78     cause memory overwriting.
80 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81     string has been matched (to stop an infinite loop). It was not recognizing
82 ph10 208 a conditional subpattern that could match an empty string if that
83 ph10 206 subpattern was within another subpattern. For example, it looped when
84 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
85 ph10 206 condition was not nested. This bug has been fixed.
86 ph10 208
87 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88     past the start of the subject in the presence of bytes with the top bit
89     set, for example "\x8aBCD".
90 ph10 211
91 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
93 ph10 200
94 ph10 211 14. Optimized (?!) to (*FAIL).
95 ph10 202
96 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97     This restricts code points to be within the range 0 to 0x10FFFF, excluding
98     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100     does: it's just the validity check that is more restrictive.
101 ph10 220
102     16. Inserted checks for integer overflows during escape sequence (backslash)
103     processing, and also fixed erroneous offset values for syntax errors during
104     backslash processing.
106 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
109 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110     caused an overrun.
111 ph10 220
112     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113     something other than just ASCII characters) inside a group that had an
114     unlimited repeat caused a loop at compile time (while checking to see
115     whether the group could match an empty string).
117 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
118     [\P{Any}] did so. (Error in the code for printing property names.)
119 ph10 210
120 ph10 220 21. An orphan \E inside a character class could cause a crash.
122     22. A repeated capturing bracket such as (A)? could cause a wild memory
123 ph10 218 reference during compilation.
124 ph10 220
125     23. There are several functions in pcre_compile() that scan along a compiled
126     expression for various reasons (e.g. to see if it's fixed length for look
127 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
128 ph10 220 present in the pattern. These operators have additional parameters compared
129     with \d, etc, and these were not being taken into account when moving along
130 ph10 218 the compiled data. Specifically:
131 ph10 220
132     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
133     length.
135     (b) An item such as \pL+ within a repeated group could cause crashes or
136 ph10 218 loops.
137 ph10 220
138 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
139 ph10 220 "reference to non-existent subpattern" error.
141 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
143 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
144 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
145 ph10 211
146 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
147 ph10 218
148 ph10 223 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
149     character were causing crashes (broken optimization).
150 ph10 224
151     27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
152     \p or \P) caused a compile-time loop.
153 ph10 226
154     28. More problems have arisen in unanchored patterns when CRLF is a valid line
155     break. For example, the unstudied pattern [\r\n]A does not match the string
156     "\r\nA" because change 7.0/46 below moves the current point on by two
157     characters after failing to match at the start. However, the pattern \nA
158     *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
159     the same is true. There doesn't seem any very clean way out of this, but
160     what I have chosen to do makes the common cases work: PCRE now takes note
161     of whether there can be an explicit match for \r or \n anywhere in the
162     pattern, and if so, 7.0/46 no longer applies. As part of this change,
163     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
164     pattern has explicit CR or LF references.
165 ph10 222
166 ph10 223
167 ph10 189 Version 7.2 19-Jun-07
168     ---------------------
170 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
171     which is apparently normally available under Windows.
172 ph10 159
173     2. Re-jig the pcregrep tests with different newline settings in an attempt
174     to make them independent of the local environment's newline setting.
175 ph10 157
176 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
177 ph10 165
178 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
179     was not 2, because the output contained actual offsets. The recent new
180 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
181     usable with all link sizes.
183 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
184     stack recursion. This gives a massive performance boost under BSD, but just
185 ph10 165 a small improvement under Linux. However, it saves one field in the frame
186 ph10 164 in all cases.
187 ph10 172
188 ph10 166 6. Added more features from the forthcoming Perl 5.10:
189 ph10 172
190 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
191     recursion call. It refers to the nth most recently opened parentheses.
192 ph10 172
193 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
194 ph10 172 to be opened parentheses.
196     (c) Conditions that refer to capturing parentheses can be specified
197 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
198 ph10 172
199 ph10 168 (d) \K resets the start of the current match so that everything before
200 ph10 172 is not part of it.
202 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
203 ph10 172
204 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
205 ph10 172 reference syntax.
206 ph10 182
207 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
208 ph10 182 alternative starts with the same number.
209 ph10 172
210 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
212 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
215     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
216     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
217 ph10 170 for detecting groups that can match an empty string.
218 ph10 159
219 ph10 172 9. A pattern with a very large number of alternatives (more than several
220     hundred) was running out of internal workspace during the pre-compile
221     phase, where pcre_compile() figures out how much memory will be needed. A
222     bit of new cunning has reduced the workspace needed for groups with
223     alternatives. The 1000-alternative test pattern now uses 12 bytes of
224     workspace instead of running out of the 4096 that are available.
225 ph10 182
226 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
227 ph10 172
228 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
229     The report of the bug said:
230 ph10 182
231 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
232     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
233 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
234 ph10 185
235 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
236 ph10 185 it matched the wrong number of bytes.
237 ph10 172
238 ph10 179
239 ph10 155 Version 7.1 24-Apr-07
240 ph10 98 ---------------------
242 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
243 ph10 122 that is more "standard", making use of automake and other Autotools. There
244 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
245     on this.
246 ph10 111
247     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
248     for recursive directory scanning broke on some systems because the files
249     are not scanned in any specific order and on different systems the order
250     was different. A call to "sort" has been inserted into RunGrepTest for the
251     approprate test as a short-term fix. In the longer term there may be an
252 ph10 100 alternative.
253 ph10 111
254 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
255 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
256     people do their own conversions for various reasons). The problems
257     concerned the use of low-level troff macros .br and .in. I have therefore
258     removed all such uses from the man pages (some were redundant, some could
259 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
260     HTML has been updated to handle .nf/.fi and to complain if it encounters
261     .br or .in.
262 ph10 111
263 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
264 ph10 123 arranged for config.h to be included in the distribution, with the name
265 ph10 111 config.h.generic, for the benefit of those who have to compile without
266     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
268     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
269     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
270 ph10 127 makevp.bat for the current PCRE, using the additional files
271 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
272 ph10 111
273     6. A Windows user reported a minor discrepancy with test 2, which turned out
274     to be caused by a trailing space on an input line that had got lost in his
275 ph10 102 copy. The trailing space was an accident, so I've just removed it.
276 ph10 111
277 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
278 ph10 111 that is needed.
280 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
281     as "const" (a) because they are and (b) because it helps the PHP
282     maintainers who have recently made a script to detect big data structures
283 ph10 111 in the php code that should be moved to the .rodata section. I remembered
284     to update Builducptable as well, so it won't revert if ucptable.h is ever
285 ph10 105 re-created.
286 ph10 111
287     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
288 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
289 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
290     support is not required. This saves 1.5-2K of code, which is important in
291 ph10 107 some applications.
292 ph10 111
293 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
294 ph10 111 so as not to refer to the tables, even though these functions will never be
295     called when UTF-8 support is disabled. Otherwise there are problems with a
296     shared library.
298 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
300     (a) It was defining its arguments as char * instead of void *.
302 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
303     a long time ago when I wrote it, but is no longer the case.
305 ph10 118 The emulated memove() is provided for those environments that have neither
306 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
307 ph10 118 is clearly not the case, as these two bugs were recently reported.
308 ph10 123
309 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
310 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
311     pages, and it removes trailing spaces from listed files. It also creates
312     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
313     case, it wraps all the #defines with #ifndefs. This script should be run
314 ph10 111 before "make dist".
315 ph10 123
316 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
317     with Unicode property support.
318 ph10 123
319     (a) For a maximizing quantifier, if the two different cases of the
320     character were of different lengths in their UTF-8 codings (there are
321     some cases like this - I found 11), and the matching function had to
322 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
323     were both the same length.
324 ph10 123
325     (b) When PCRE was configured to use the heap rather than the stack for
326     recursion during matching, it was not correctly preserving the data for
327     the other case of a UTF-8 character when checking ahead for a match
328     while processing a minimizing repeat. If the check also involved
329 ph10 115 matching a wide character, but failed, corruption could cause an
330     erroneous result when trying to check for a repeat of the original
331     character.
332 ph10 123
333 ph10 116 13. Some tidying changes to the testing mechanism:
334 ph10 98
335 ph10 116 (a) The RunTest script now detects the internal link size and whether there
336     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
337 ph10 123 values substituted by "configure". (The RunGrepTest script already did
338     this for UTF-8.) The configure.ac script no longer substitutes the
339     relevant variables.
341 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
342     with length and offset values. This means that the output is different
343     for different internal link sizes. Test 2 is skipped for link sizes
344     other than 2 because of this, bypassing the problem. Unfortunately,
345     there was also a test in test 3 (the locale tests) that used /B and
346 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
347     I have added a new /Z option to pcretest that replaces the length and
348     offset values with spaces. This is now used to make test 3 independent
349 ph10 122 of link size. (Test 2 will be tidied up later.)
350 ph10 123
351     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
352 ph10 122 segmentation fault instead of returning the appropriate error message.
353 ph10 134
354 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
355 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
356     This doesn't seem right; it now treats the CRLF combination as the line
357     ending, and so does not match in that case. It's only a pattern such as ^$
358     that would hit this one: something like ^ABC$ would have failed after \r
359     and then tried again after \r\n.
361 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
362 ph10 134 in an attempt to make files that differ only in their line terminators
363     compare equal. This works on Linux.
364 ph10 142
365 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
366     as it exited. This is now fixed, thanks to valgrind.
367 ph10 142
368 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
369 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
370     was because its rules for how to advance for /g after matching an empty
371 ph10 143 string at the end of a line did not allow for this case. They now check for
372     it specially.
373 ph10 150
374     20. pcretest is supposed to handle patterns and data of any length, by
375     extending its buffers when necessary. It was getting this wrong when the
376 ph10 147 buffer for a data line had to be extended.
377 ph10 150
378 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
379 ph10 150 CRLF as a newline sequence.
380 ph10 152
381 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
382 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
383     I have nevertheless tidied it up.
384 ph10 111
385 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
386 ph10 123
387 ph10 153 24. Added a man page for pcre-config.
388 ph10 152
389 ph10 153
390 nigel 93 Version 7.0 19-Dec-06
391     ---------------------
393     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
394     moving to gcc 4.1.1.
396     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
397     sys/time.h, which is documented as needed for this function. It doesn't
398     seem to matter on Linux, but it showed up on some releases of OS X.
400     3. It seems that there are systems where bytes whose values are greater than
401     127 match isprint() in the "C" locale. The "C" locale should be the
402     default when a C program starts up. In most systems, only ASCII printing
403     characters match isprint(). This difference caused the output from pcretest
404     to vary, making some of the tests fail. I have changed pcretest so that:
406     (a) When it is outputting text in the compiled version of a pattern, bytes
407     other than 32-126 are always shown as hex escapes.
409     (b) When it is outputting text that is a matched part of a subject string,
410     it does the same, unless a different locale has been set for the match
411     (using the /L modifier). In this case, it uses isprint() to decide.
413     4. Fixed a major bug that caused incorrect computation of the amount of memory
414     required for a compiled pattern when options that changed within the
415     pattern affected the logic of the preliminary scan that determines the
416     length. The relevant options are -x, and -i in UTF-8 mode. The result was
417     that the computed length was too small. The symptoms of this bug were
418     either the PCRE error "internal error: code overflow" from pcre_compile(),
419     or a glibc crash with a message such as "pcretest: free(): invalid next
420     size (fast)". Examples of patterns that provoked this bug (shown in
421     pcretest format) are:
423     /(?-x: )/x
424     /(?x)(?-x: \s*#\s*)/
425     /((?i)[\x{c0}])/8
426     /(?i:[\x{c0}])/8
428     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
429     is now done differently.
431     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
432     wrapper classes; (b) implement a new function in the C++ scanner that is
433     more efficient than the old way of doing things because it avoids levels of
434     recursion in the regex matching; (c) add a paragraph to the documentation
435     for the FullMatch() function.
437     6. The escape sequence \n was being treated as whatever was defined as
438     "newline". Not only was this contrary to the documentation, which states
439     that \n is character 10 (hex 0A), but it also went horribly wrong when
440     "newline" was defined as CRLF. This has been fixed.
442     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
443     was being set to -1 for the "end of line" case (supposedly a value that no
444     character can have). Though this value is never used (the check for end of
445     line is "zero bytes in current character"), it caused compiler complaints.
446     I've changed it to 0xffffffff.
448     8. In pcre_version.c, the version string was being built by a sequence of
449     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
450     string (as it is for production releases) called a macro with an empty
451     argument. The C standard says the result of this is undefined. The gcc
452     compiler treats it as an empty string (which was what was wanted) but it is
453     reported that Visual C gives an error. The source has been hacked around to
454     avoid this problem.
456     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
457     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
458     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
459     of them did).
461     10. Originally, pcretest opened its input and output without "b"; then I was
462     told that "b" was needed in some environments, so it was added for release
463     5.0 to both the input and output. (It makes no difference on Unix-like
464     systems.) Later I was told that it is wrong for the input on Windows. I've
465     now abstracted the modes into two macros, to make it easier to fiddle with
466     them, and removed "b" from the input mode under Windows.
468     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
470     12. Added -help and --help to pcretest as an official way of being reminded
471     of the options.
473     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
474     and pcrecpp.cc because they annoy compilers at high warning levels.
476     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
478     15. Fixed an occurrence of == in configure.ac that should have been = (shell
479     scripts are not C programs :-) and which was not noticed because it works
480     on Linux.
482     16. pcretest is supposed to handle any length of pattern and data line (as one
483     line or as a continued sequence of lines) by extending its input buffer if
484     necessary. This feature was broken for very long pattern lines, leading to
485     a string of junk being passed to pcre_compile() if the pattern was longer
486     than about 50K.
488     17. I have done a major re-factoring of the way pcre_compile() computes the
489     amount of memory needed for a compiled pattern. Previously, there was code
490     that made a preliminary scan of the pattern in order to do this. That was
491     OK when PCRE was new, but as the facilities have expanded, it has become
492     harder and harder to keep it in step with the real compile phase, and there
493     have been a number of bugs (see for example, 4 above). I have now found a
494     cunning way of running the real compile function in a "fake" mode that
495     enables it to compute how much memory it would need, while actually only
496     ever using a few hundred bytes of working memory and without too many
497     tests of the mode. This should make future maintenance and development
498     easier. A side effect of this work is that the limit of 200 on the nesting
499     depth of parentheses has been removed (though this was never a serious
500     limitation, I suspect). However, there is a downside: pcre_compile() now
501     runs more slowly than before (30% or more, depending on the pattern). I
502     hope this isn't a big issue. There is no effect on runtime performance.
504     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
505     newline (only possible for the last line of a file) and it was a
506     pattern that set a locale (followed by /Lsomething), pcretest crashed.
508     19. Added additional timing features to pcretest. (1) The -tm option now times
509     matching only, not compiling. (2) Both -t and -tm can be followed, as a
510     separate command line item, by a number that specifies the number of
511     repeats to use when timing. The default is 50000; this gives better
512     precision, but takes uncomfortably long for very large patterns.
514     20. Extended pcre_study() to be more clever in cases where a branch of a
515     subpattern has no definite first character. For example, (a*|b*)[cd] would
516     previously give no result from pcre_study(). Now it recognizes that the
517     first character must be a, b, c, or d.
519     21. There was an incorrect error "recursive call could loop indefinitely" if
520     a subpattern (or the entire pattern) that was being tested for matching an
521     empty string contained only one non-empty item after a nested subpattern.
522     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
523     incorrectly, because the \d was being skipped in the check.
525     22. The pcretest program now has a new pattern option /B and a command line
526     option -b, which is equivalent to adding /B to every pattern. This causes
527     it to show the compiled bytecode, without the additional information that
528     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
529     is the same as /B/I).
531     23. A new optimization is now able automatically to treat some sequences such
532     as a*b as a*+b. More specifically, if something simple (such as a character
533     or a simple class like \d) has an unlimited quantifier, and is followed by
534     something that cannot possibly match the quantified thing, the quantifier
535     is automatically "possessified".
537     24. A recursive reference to a subpattern whose number was greater than 39
538     went wrong under certain circumstances in UTF-8 mode. This bug could also
539     have affected the operation of pcre_study().
541     25. Realized that a little bit of performance could be had by replacing
542     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
544     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
546     27. Possessive quantifiers such as a++ were previously implemented by turning
547     them into atomic groups such as ($>a+). Now they have their own opcodes,
548     which improves performance. This includes the automatically created ones
549     from 23 above.
551     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
552     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
553     the first matched character to be a colon. This applied both to named and
554     numbered groups.
556     29. The ucpinternal.h header file was missing its idempotency #ifdef.
558     30. I was sent a "project" file called libpcre.a.dev which I understand makes
559     building PCRE on Windows easier, so I have included it in the distribution.
561     31. There is now a check in pcretest against a ridiculously large number being
562     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
563     loop, the loop is abandoned.
565     32. Forward references to subpatterns in conditions such as (?(2)...) where
566     subpattern 2 is defined later cause pcre_compile() to search forwards in
567     the pattern for the relevant set of parentheses. This search went wrong
568     when there were unescaped parentheses in a character class, parentheses
569     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
571     33. "Subroutine" calls and backreferences were previously restricted to
572     referencing subpatterns earlier in the regex. This restriction has now
573     been removed.
575     34. Added a number of extra features that are going to be in Perl 5.10. On the
576     whole, these are just syntactic alternatives for features that PCRE had
577     previously implemented using the Python syntax or my own invention. The
578     other formats are all retained for compatibility.
580     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
581     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
582     also .NET compatible.
584     (b) A recursion or subroutine call to a named group can now be defined as
585     (?&name) as well as (?P>name).
587     (c) A backreference to a named group can now be defined as \k<name> or
588     \k'name' as well as (?P=name). The new forms, as well as being in Perl
589     5.10, are also .NET compatible.
591     (d) A conditional reference to a named group can now use the syntax
592     (?(<name>) or (?('name') as well as (?(name).
594     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
595     groups (named and numbered) that are never evaluated inline, but can be
596     called as "subroutines" from elsewhere. In effect, the DEFINE condition
597     is always false. There may be only one alternative in such a group.
599     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
600     as the simple (?(R). The condition is true only if the most recent
601     recursion is that of the given number or name. It does not search out
602     through the entire recursion stack.
604     (g) The escape \gN or \g{N} has been added, where N is a positive or
605     negative number, specifying an absolute or relative reference.
607     35. Tidied to get rid of some further signed/unsigned compiler warnings and
608     some "unreachable code" warnings.
610     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
611     things, this adds five new scripts.
613     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
614     There were also incompatibilities regarding the handling of \Q..\E inside
615     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
616     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
618     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
619     matches an empty string, and forcibly breaks the loop. There were bugs in
620     this code in non-simple cases. For a pattern such as ^(a()*)* matched
621     against aaaa the result was just "a" rather than "aaaa", for example. Two
622     separate and independent bugs (that affected different cases) have been
623     fixed.
625     39. Refactored the code to abolish the use of different opcodes for small
626     capturing bracket numbers. This is a tidy that I avoided doing when I
627     removed the limit on the number of capturing brackets for 3.5 back in 2001.
628     The new approach is not only tidier, it makes it possible to reduce the
629     memory needed to fix the previous bug (38).
631     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
632     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
633     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
634     mode.
636     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
637     report.
639     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
640     copy construction and assignment in the C++ wrapper.
642     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
643     couple of bugs that could have given wrong results in the "--newline=crlf"
644     case.
646     44. Added a number of casts and did some reorganization of signed/unsigned int
647     variables following suggestions from Dair Grant. Also renamed the variable
648     "this" as "item" because it is a C++ keyword.
650     45. Arranged for dftables to add
652     #include "pcre_internal.h"
654     to pcre_chartables.c because without it, gcc 4.x may remove the array
655     definition from the final binary if PCRE is built into a static library and
656     dead code stripping is activated.
658     46. For an unanchored pattern, if a match attempt fails at the start of a
659     newline sequence, and the newline setting is CRLF or ANY, and the next two
660     characters are CRLF, advance by two characters instead of one.
663 nigel 91 Version 6.7 04-Jul-06
664     ---------------------
666     1. In order to handle tests when input lines are enormously long, pcretest has
667     been re-factored so that it automatically extends its buffers when
668     necessary. The code is crude, but this _is_ just a test program. The
669     default size has been increased from 32K to 50K.
671     2. The code in pcre_study() was using the value of the re argument before
672     testing it for NULL. (Of course, in any sensible call of the function, it
673     won't be NULL.)
675     3. The memmove() emulation function in pcre_internal.h, which is used on
676     systems that lack both memmove() and bcopy() - that is, hardly ever -
677     was missing a "static" storage class specifier.
679     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
680     containing an extended class (one that cannot be represented by a bitmap
681     because it contains high-valued characters or Unicode property items, e.g.
682     [\pZ]). Almost always one would set UTF-8 mode when processing such a
683     pattern, but PCRE should not loop if you do not (it no longer does).
684     [Detail: two cases were found: (a) a repeated subpattern containing an
685     extended class; (b) a recursive reference to a subpattern that followed a
686     previous extended class. It wasn't skipping over the extended class
687     correctly when UTF-8 mode was not set.]
689     5. A negated single-character class was not being recognized as fixed-length
690     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
691     compile error "lookbehind assertion is not fixed length".
693     6. The RunPerlTest auxiliary script was showing an unexpected difference
694     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
695     write a Perl script that can interpret lines of an input file either as
696     byte characters or as UTF-8, which is what "perltest" was being required to
697     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
698     can't do is switch easily at run time between having the "use utf8;" pragma
699     or not. In the end, I fudged it by using the RunPerlTest script to insert
700     "use utf8;" explicitly for the UTF-8 tests.
702     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
703     the end of the subject string, contrary to the documentation and to what
704     Perl does. This was true of both matching functions. Now it matches only at
705     the start of the subject and immediately after *internal* newlines.
707     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
708     a pointer to an int instead of a pointer to an unsigned long int. This
709     caused problems on 64-bit systems.
711     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
712     instance of the 'standard' template library not being so standard".
714     10. There was no check on the number of named subpatterns nor the maximum
715     length of a subpattern name. The product of these values is used to compute
716     the size of the memory block for a compiled pattern. By supplying a very
717     long subpattern name and a large number of named subpatterns, the size
718     computation could be caused to overflow. This is now prevented by limiting
719     the length of names to 32 characters, and the number of named subpatterns
720     to 10,000.
722     11. Subpatterns that are repeated with specific counts have to be replicated in
723     the compiled pattern. The size of memory for this was computed from the
724     length of the subpattern and the repeat count. The latter is limited to
725     65535, but there was no limit on the former, meaning that integer overflow
726     could in principle occur. The compiled length of a repeated subpattern is
727     now limited to 30,000 bytes in order to prevent this.
729     12. Added the optional facility to have named substrings with the same name.
731     13. Added the ability to use a named substring as a condition, using the
732     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
733     are numbers (not recommended). Forward references are permitted.
735     14. Added forward references in named backreferences (if you see what I mean).
737     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
738     pattern could run off the end of the subject. For example, the pattern
739     "(?s)(.{1,5})"8 did this with the subject "ab".
741     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
742     PCRE_CASELESS was set when matching characters that were quantified with ?
743     or *.
745     17. A character class other than a single negated character that had a minimum
746     but no maximum quantifier - for example [ab]{6,} - was not handled
747     correctly by pce_dfa_exec(). It would match only one character.
749     18. A valid (though odd) pattern that looked like a POSIX character
750     class but used an invalid character after [ (for example [[,abc,]]) caused
751     pcre_compile() to give the error "Failed: internal error: code overflow" or
752     in some cases to crash with a glibc free() error. This could even happen if
753     the pattern terminated after [[ but there just happened to be a sequence of
754     letters, a binary zero, and a closing ] in the memory that followed.
756     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
757     over the years. Originally (before any Unicode support), just the bottom 8
758     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
759     output from "man perlunicode" includes this:
761     The regular expression compiler produces polymorphic opcodes. That
762     is, the pattern adapts to the data and automatically switches to
763     the Unicode character scheme when presented with Unicode data--or
764     instead uses a traditional byte scheme when presented with byte
765     data.
767     Sadly, a wide octal escape does not cause a switch, and in a string with
768     no other multibyte characters, these octal escapes are treated as before.
769     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
770     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
771     Unicode string.
773     I have not perpetrated such confusion in PCRE. Up till now, it took just
774     the bottom 8 bits, as in old Perl. I have now made octal escapes with
775     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
776     translate to the appropriate multibyte character.
778     29. Applied some refactoring to reduce the number of warnings from Microsoft
779     and Borland compilers. This has included removing the fudge introduced
780     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
781     a warning about an unused variable.
783     21. PCRE has not included VT (character 0x0b) in the set of whitespace
784     characters since release 4.0, because Perl (from release 5.004) does not.
785     [Or at least, is documented not to: some releases seem to be in conflict
786     with the documentation.] However, when a pattern was studied with
787     pcre_study() and all its branches started with \s, PCRE still included VT
788     as a possible starting character. Of course, this did no harm; it just
789     caused an unnecessary match attempt.
791     22. Removed a now-redundant internal flag bit that recorded the fact that case
792     dependency changed within the pattern. This was once needed for "required
793     byte" processing, but is no longer used. This recovers a now-scarce options
794     bit. Also moved the least significant internal flag bit to the most-
795     significant bit of the word, which was not previously used (hangover from
796     the days when it was an int rather than a uint) to free up another bit for
797     the future.
799     23. Added support for CRLF line endings as well as CR and LF. As well as the
800     default being selectable at build time, it can now be changed at runtime
801     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
802     specify that it is scanning data with non-default line endings.
804     24. Changed the definition of CXXLINK to make it agree with the definition of
805     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
807     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
808     recursions. This makes a big different to stack usage for some patterns.
810     26. If a subpattern containing a named recursion or subroutine reference such
811     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
812     the space required for the compiled pattern went wrong and gave too small a
813     value. Depending on the environment, this could lead to "Failed: internal
814     error: code overflow at offset 49" or "glibc detected double free or
815     corruption" errors.
817     27. Applied patches from Google (a) to support the new newline modes and (b) to
818     advance over multibyte UTF-8 characters in GlobalReplace.
820     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
821     difference for some implementation of PCRE in some Windows version.
823     29. Added some extra testing facilities to pcretest:
825     \q<number> in a data line sets the "match limit" value
826     \Q<number> in a data line sets the "match recursion limt" value
827     -S <number> sets the stack size, where <number> is in megabytes
829     The -S option isn't available for Windows.
832 nigel 89 Version 6.6 06-Feb-06
833     ---------------------
835     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
836     in pcreposix.h. I have copied the definition from pcre.h.
838     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
839     because pcre.h is no longer a built file.
841     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
842     not normally included in the compiled code.
845 nigel 87 Version 6.5 01-Feb-06
846     ---------------------
848     1. When using the partial match feature with pcre_dfa_exec(), it was not
849     anchoring the second and subsequent partial matches at the new starting
850     point. This could lead to incorrect results. For example, with the pattern
851     /1234/, partially matching against "123" and then "a4" gave a match.
853     2. Changes to pcregrep:
855     (a) All non-match returns from pcre_exec() were being treated as failures
856     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
857     error message is output. Some extra information is given for the
859     probably the only errors that are likely to be caused by users (by
860     specifying a regex that has nested indefinite repeats, for instance).
861     If there are more than 20 of these errors, pcregrep is abandoned.
863     (b) A binary zero was treated as data while matching, but terminated the
864     output line if it was written out. This has been fixed: binary zeroes
865     are now no different to any other data bytes.
867     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
868     used to set a locale for matching. The --locale=xxxx long option has
869     been added (no short equivalent) to specify a locale explicitly on the
870     pcregrep command, overriding the environment variables.
872     (d) When -B was used with -n, some line numbers in the output were one less
873     than they should have been.
875     (e) Added the -o (--only-matching) option.
877     (f) If -A or -C was used with -c (count only), some lines of context were
878     accidentally printed for the final match.
880     (g) Added the -H (--with-filename) option.
882     (h) The combination of options -rh failed to suppress file names for files
883     that were found from directory arguments.
885     (i) Added the -D (--devices) and -d (--directories) options.
887     (j) Added the -F (--fixed-strings) option.
889     (k) Allow "-" to be used as a file name for -f as well as for a data file.
891     (l) Added the --colo(u)r option.
893     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
894     is not present by default.
896     3. A nasty bug was discovered in the handling of recursive patterns, that is,
897     items such as (?R) or (?1), when the recursion could match a number of
898     alternatives. If it matched one of the alternatives, but subsequently,
899     outside the recursion, there was a failure, the code tried to back up into
900     the recursion. However, because of the way PCRE is implemented, this is not
901     possible, and the result was an incorrect result from the match.
903     In order to prevent this happening, the specification of recursion has
904     been changed so that all such subpatterns are automatically treated as
905     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
907     4. I had overlooked the fact that, in some locales, there are characters for
908     which isalpha() is true but neither isupper() nor islower() are true. In
909     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
910     and ordfeminine) are like this. This affected the treatment of \w and \W
911     when they appeared in character classes, but not when they appeared outside
912     a character class. The bit map for "word" characters is now created
913     separately from the results of isalnum() instead of just taking it from the
914     upper, lower, and digit maps. (Plus the underscore character, of course.)
916     5. The above bug also affected the handling of POSIX character classes such as
917     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
918     permanent tables. Instead, the bit maps for such a class were previously
919     created as the appropriate unions of the upper, lower, and digit bitmaps.
920     Now they are created by subtraction from the [[:word:]] class, which has
921     its own bitmap.
923     6. The [[:blank:]] character class matches horizontal, but not vertical space.
924     It is created by subtracting the vertical space characters (\x09, \x0a,
925     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
926     subtraction was done in the overall bitmap for a character class, meaning
927     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
928     be recognized. This bug has been fixed.
930     7. Patches from the folks at Google:
932     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
933     real life, but is still worth protecting against".
935     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
936     regular expressions".
938     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
939     have it.
941     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
942     "configure" and the latter not, in order to fix a problem somebody had
943     with compiling the Arg class on HP-UX.
945     (e) Improve the error-handling of the C++ wrapper a little bit.
947     (f) New tests for checking recursion limiting.
949     8. The pcre_memmove() function, which is used only if the environment does not
950     have a standard memmove() function (and is therefore rarely compiled),
951     contained two bugs: (a) use of int instead of size_t, and (b) it was not
952     returning a result (though PCRE never actually uses the result).
954     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
955     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
956     returned instead of calling malloc() with an overflowing number that would
957     most likely cause subsequent chaos.
959     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
961     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
962     with this option is matched, the nmatch and pmatch options of regexec() are
963     ignored.
965     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
966     provided in case anyone wants to the the POSIX interface with UTF-8
967     strings.
969     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
970     C++ linking (needed for some HP-UX environments).
972     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
973     (unused parameter) and in the pcre_printint() function (omitted "default"
974     switch label when the default is to do nothing).
976     15. Added some code to make it possible, when PCRE is compiled as a C++
977     library, to replace subject pointers for pcre_exec() with a smart pointer
978     class, thus making it possible to process discontinuous strings.
980     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
981     much the same function. They were added by different people who were trying
982     to make PCRE easy to compile on non-Unix systems. It has been suggested
983     that PCRE_EXPORT be abolished now that there is more automatic apparatus
984     for compiling on Windows systems. I have therefore replaced it with
985     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
986     defaults to "extern" for C or "extern C" for C++, which works fine on
987     Unix-like systems. It is now possible to override the value of PCRE_DATA_
988     SCOPE with something explicit in config.h. In addition:
990     (a) pcreposix.h still had just "extern" instead of either of these macros;
991     I have replaced it with PCRE_DATA_SCOPE.
993     (b) Functions such as _pcre_xclass(), which are internal to the library,
994     but external in the C sense, all had PCRE_EXPORT in their definitions.
995     This is apparently wrong for the Windows case, so I have removed it.
996     (It makes no difference on Unix-like systems.)
998     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
999     of recursive calls to match(). This is different to MATCH_LIMIT because
1000     that limits the total number of calls to match(), not all of which increase
1001     the depth of recursion. Limiting the recursion depth limits the amount of
1002     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1003     when PCRE is compiled, and changed at run time. A patch from Google adds
1004     this functionality to the C++ interface.
1006     18. Changes to the handling of Unicode character properties:
1008     (a) Updated the table to Unicode 4.1.0.
1010     (b) Recognize characters that are not in the table as "Cn" (undefined).
1012     (c) I revised the way the table is implemented to a much improved format
1013     which includes recognition of ranges. It now supports the ranges that
1014     are defined in UnicodeData.txt, and it also amalgamates other
1015     characters into ranges. This has reduced the number of entries in the
1016     table from around 16,000 to around 3,000, thus reducing its size
1017     considerably. I realized I did not need to use a tree structure after
1018     all - a binary chop search is just as efficient. Having reduced the
1019     number of entries, I extended their size from 6 bytes to 8 bytes to
1020     allow for more data.
1022     (d) Added support for Unicode script names via properties such as \p{Han}.
1024     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1025     matching that character.
1027     20. When matching a repeated Unicode property with a minimum greater than zero,
1028     (for example \pL{2,}), PCRE could look past the end of the subject if it
1029     reached it while seeking the minimum number of characters. This could
1030     happen only if some of the characters were more than one byte long, because
1031     there is a check for at least the minimum number of bytes.
1033     21. Refactored the implementation of \p and \P so as to be more general, to
1034     allow for more different types of property in future. This has changed the
1035     compiled form incompatibly. Anybody with saved compiled patterns that use
1036     \p or \P will have to recompile them.
1038     22. Added "Any" and "L&" to the supported property types.
1040     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1041     but give a compile time error if the value is greater than 0xff.
1043     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1044     accidentally not being installed or uninstalled.
1046     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1047     made were to insert the current release number. This seemed silly, because
1048     it made things harder for people building PCRE on systems that don't run
1049     "configure". I have turned pcre.h into a distributed file, no longer built
1050     by "configure", with the version identification directly included. There is
1051     no longer a pcre.h.in file.
1053     However, this change necessitated a change to the pcre-config script as
1054     well. It is built from pcre-config.in, and one of the substitutions was the
1055     release number. I have updated configure.ac so that ./configure now finds
1056     the release number by grepping pcre.h.
1058     26. Added the ability to run the tests under valgrind.
1061 nigel 85 Version 6.4 05-Sep-05
1062     ---------------------
1064     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1065     "--" to be printed when multiple files were scanned, even when none of the
1066     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1067     consider it to be a bug, and have restored the previous behaviour.
1069     2. A couple of code tidies to get rid of compiler warnings.
1071     3. The pcretest program used to cheat by referring to symbols in the library
1072     whose names begin with _pcre_. These are internal symbols that are not
1073     really supposed to be visible externally, and in some environments it is
1074     possible to suppress them. The cheating is now confined to including
1075     certain files from the library's source, which is a bit cleaner.
1077     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1078     file's purpose clearer.
1080     5. Reorganized pcre_ucp_findchar().
1083 nigel 83 Version 6.3 15-Aug-05
1084     ---------------------
1086     1. The file libpcre.pc.in did not have general read permission in the tarball.
1088     2. There were some problems when building without C++ support:
1090     (a) If C++ support was not built, "make install" and "make test" still
1091     tried to test it.
1093     (b) There were problems when the value of CXX was explicitly set. Some
1094     changes have been made to try to fix these, and ...
1096     (c) --disable-cpp can now be used to explicitly disable C++ support.
1098     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1099     backslash in a target when C++ was disabled. This confuses some
1100     versions of "make", apparently. Using an intermediate variable solves
1101     this. (Same for CPP_LOBJ.)
1103     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1104     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1105     necessary on certain architectures.
1107     4. Added a setting of -export-symbols-regex to the link command to remove
1108     those symbols that are exported in the C sense, but actually are local
1109     within the library, and not documented. Their names all begin with
1110     "_pcre_". This is not a perfect job, because (a) we have to except some
1111     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1112     available (and never for static libraries). I have made a note to try to
1113     find a way round (a) in the future.
1116 nigel 81 Version 6.2 01-Aug-05
1117     ---------------------
1119     1. There was no test for integer overflow of quantifier values. A construction
1120     such as {1111111111111111} would give undefined results. What is worse, if
1121     a minimum quantifier for a parenthesized subpattern overflowed and became
1122     negative, the calculation of the memory size went wrong. This could have
1123     led to memory overwriting.
1125     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1127     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1128     operating environments where this matters.
1130     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1131     PCRE options from within the C++ wrapper.
1133     5. Named capturing subpatterns were not being correctly counted when a pattern
1134     was compiled. This caused two problems: (a) If there were more than 100
1135     such subpatterns, the calculation of the memory needed for the whole
1136     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1137     back references of the form \12, where the number was greater than 9, were
1138     not recognized as back references, even though there were sufficient
1139     previous subpatterns.
1141     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1142     versions of gcc, e.g. 2.95.4.
1145 nigel 79 Version 6.1 21-Jun-05
1146     ---------------------
1148     1. There was one reference to the variable "posix" in pcretest.c that was not
1149     surrounded by "#if !defined NOPOSIX".
1151     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1152     the cross-check on the old pcre_info() function, for the benefit of the
1153     cut-down version of PCRE that is currently imported into Exim.
1155     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1156     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1157     patterns that start (?i) but I don't think that matters. The use of (?i) is
1158     just an example; this all applies to the other options as well.
1160     4. Since libtool seems to echo the compile commands it is issuing, the output
1161     from "make" can be reduced a bit by putting "@" in front of each libtool
1162     compile command.
1164     5. Patch from the folks at Google for configure.in to be a bit more thorough
1165     in checking for a suitable C++ installation before trying to compile the
1166     C++ stuff. This should fix a reported problem when a compiler was present,
1167     but no suitable headers.
1169     6. The man pages all had just "PCRE" as their title. I have changed them to
1170     be the relevant file name. I have also arranged that these names are
1171     retained in the file doc/pcre.txt, which is a concatenation in text format
1172     of all the man pages except the little individual ones for each function.
1174     7. The NON-UNIX-USE file had not been updated for the different set of source
1175     files that come with release 6. I also added a few comments about the C++
1176     wrapper.
1179 nigel 77 Version 6.0 07-Jun-05
1180     ---------------------
1182     1. Some minor internal re-organization to help with my DFA experiments.
1184     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1185     didn't matter for the library itself when fully configured, but did matter
1186     when compiling without UCP support, or within Exim, where the ucp files are
1187     not imported.
1189     3. Refactoring of the library code to split up the various functions into
1190     different source modules. The addition of the new DFA matching code (see
1191     below) to a single monolithic source would have made it really too
1192     unwieldy, quite apart from causing all the code to be include in a
1193     statically linked application, when only some functions are used. This is
1194     relevant even without the DFA addition now that patterns can be compiled in
1195     one application and matched in another.
1197     The downside of splitting up is that there have to be some external
1198     functions and data tables that are used internally in different modules of
1199     the library but which are not part of the API. These have all had their
1200     names changed to start with "_pcre_" so that they are unlikely to clash
1201     with other external names.
1203     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1204     a different (DFA) algorithm. Although it is slower than the original
1205     function, it does have some advantages for certain types of matching
1206     problem.
1208     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1209     including restarting after a partial match.
1211     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1212     defined when compiling for Windows was sent to me. I have put it into the
1213     code, though I have no means of testing or verifying it.
1215     7. Added the pcre_refcount() auxiliary function.
1217     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1218     match before or at the first newline in the subject string. In pcretest,
1219     the /f option on a pattern can be used to set this.
1221     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1222     would behave wrongly. This has been present in PCRE since release 4.0.
1224     10. A number of changes to the pcregrep command:
1226     (a) Refactored how -x works; insert ^(...)$ instead of setting
1227     PCRE_ANCHORED and checking the length, in preparation for adding
1228     something similar for -w.
1230     (b) Added the -w (match as a word) option.
1232     (c) Refactored the way lines are read and buffered so as to have more
1233     than one at a time available.
1235     (d) Implemented a pcregrep test script.
1237     (e) Added the -M (multiline match) option. This allows patterns to match
1238     over several lines of the subject. The buffering ensures that at least
1239     8K, or the rest of the document (whichever is the shorter) is available
1240     for matching (and similarly the previous 8K for lookbehind assertions).
1242     (f) Changed the --help output so that it now says
1244     -w, --word-regex(p)
1246     instead of two lines, one with "regex" and the other with "regexp"
1247     because that confused at least one person since the short forms are the
1248     same. (This required a bit of code, as the output is generated
1249     automatically from a table. It wasn't just a text change.)
1251     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1252     option but starts with a hyphen. Could be a pattern or a path name
1253     starting with a hyphen, for instance.
1255     (h) "-" can be given as a file name to represent stdin.
1257     (i) When file names are being printed, "(standard input)" is used for
1258     the standard input, for compatibility with GNU grep. Previously
1259     "<stdin>" was used.
1261     (j) The option --label=xxx can be used to supply a name to be used for
1262     stdin when file names are being printed. There is no short form.
1264     (k) Re-factored the options decoding logic because we are going to add
1265     two more options that take data. Such options can now be given in four
1266     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1268     (l) Added the -A, -B, and -C options for requesting that lines of context
1269     around matches be printed.
1271     (m) Added the -L option to print the names of files that do not contain
1272     any matching lines, that is, the complement of -l.
1274     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1275     continue to scan other files.
1277     (o) The -s option was incorrectly implemented. For compatibility with other
1278     greps, it now suppresses the error message for a non-existent or non-
1279     accessible file (but not the return code). There is a new option called
1280     -q that suppresses the output of matching lines, which was what -s was
1281     previously doing.
1283     (p) Added --include and --exclude options to specify files for inclusion
1284     and exclusion when recursing.
1286     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1287     Hopefully, it now does.
1289     12. Missing cast in pcre_study().
1291     13. Added an "uninstall" target to the makefile.
1293     14. Replaced "extern" in the function prototypes in Makefile.in with
1294     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1295     world, but is set differently for Windows.
1297     15. Added a second compiling function called pcre_compile2(). The only
1298     difference is that it has an extra argument, which is a pointer to an
1299     integer error code. When there is a compile-time failure, this is set
1300     non-zero, in addition to the error test pointer being set to point to an
1301     error message. The new argument may be NULL if no error number is required
1302     (but then you may as well call pcre_compile(), which is now just a
1303     wrapper). This facility is provided because some applications need a
1304     numeric error indication, but it has also enabled me to tidy up the way
1305     compile-time errors are handled in the POSIX wrapper.
1307     16. Added VPATH=.libs to the makefile; this should help when building with one
1308     prefix path and installing with another. (Or so I'm told by someone who
1309     knows more about this stuff than I do.)
1311     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1312     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1313     match everything, including newlines. This is not POSIX-compatible, but
1314     somebody wanted the feature. From pcretest it can be activated by using
1315     both the P and the s flags.
1317     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1319     19. libpcre.pc was being incorrectly installed as executable.
1321     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1322     it now also looks for '\r' so that it will work unmodified on Windows.
1324     21. Added Google's contributed C++ wrapper to the distribution.
1326     22. Added some untidy missing memory free() calls in pcretest, to keep
1327     Electric Fence happy when testing.
1331 nigel 75 Version 5.0 13-Sep-04
1332     ---------------------
1334     1. Internal change: literal characters are no longer packed up into items
1335     containing multiple characters in a single byte-string. Each character
1336     is now matched using a separate opcode. However, there may be more than one
1337     byte in the character in UTF-8 mode.
1339     2. The pcre_callout_block structure has two new fields: pattern_position and
1340     next_item_length. These contain the offset in the pattern to the next match
1341     item, and its length, respectively.
1343     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1344     insertion of callouts before each pattern item. Added the /C option to
1345     pcretest to make use of this.
1347     4. On the advice of a Windows user, the lines
1349     #if defined(_WIN32) || defined(WIN32)
1350     _setmode( _fileno( stdout ), 0x8000 );
1351     #endif /* defined(_WIN32) || defined(WIN32) */
1353     have been added to the source of pcretest. This apparently does useful
1354     magic in relation to line terminators.
1356     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1357     for the benefit of those environments where the "b" makes a difference.
1359     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1360     to know about it. I have put a hack into configure.in that adds in code
1361     to set GCC=yes if CC=icc. This seems to end up at a point in the
1362     generated configure script that is early enough to affect the setting of
1363     compiler options, which is what is needed, but I have no means of testing
1364     whether it really works. (The user who reported this had patched the
1365     generated configure script, which of course I cannot do.)
1367     LATER: After change 22 below (new libtool files), the configure script
1368     seems to know about icc (and also ecc). Therefore, I have commented out
1369     this hack in configure.in.
1371     7. Added support for pkg-config (2 patches were sent in).
1373     8. Negated POSIX character classes that used a combination of internal tables
1374     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1375     [[:^ascii]]. Typically, they would match almost any characters. The other
1376     POSIX classes were not broken in this way.
1378     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1379     to find the match, as PCRE was deluded into thinking that the match had to
1380     start at the start point or following a newline. The same bug applied to
1381     patterns with negative forward assertions or any backward assertions
1382     preceding ".*" at the start, unless the pattern required a fixed first
1383     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1385     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1386     starting at the last subject character, bytes beyond the end of the subject
1387     string were read.
1389     11. Renamed the variable "class" as "classbits" to make life easier for C++
1390     users. (Previously there was a macro definition, but it apparently wasn't
1391     enough.)
1393     12. Added the new field "tables" to the extra data so that tables can be passed
1394     in at exec time, or the internal tables can be re-selected. This allows
1395     a compiled regex to be saved and re-used at a later time by a different
1396     program that might have everything at different addresses.
1398     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1399     -R library as well as a -L library.
1401     14. The debugging options of pcretest (-d on the command line or D on a
1402     pattern) showed incorrect output for anything following an extended class
1403     that contained multibyte characters and which was followed by a quantifier.
1405     15. Added optional support for general category Unicode character properties
1406     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1407     support. It adds about 90K to the size of the library. The meanings of the
1408     inbuilt class escapes such as \d and \s have NOT been changed.
1410     16. Updated pcredemo.c to include calls to free() to release the memory for the
1411     compiled pattern.
1413     17. The generated file chartables.c was being created in the source directory
1414     instead of in the building directory. This caused the build to fail if the
1415     source directory was different from the building directory, and was
1416     read-only.
1418     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1419     file. No doubt somebody will tell me if they don't make sense... Also added
1420     Dan Mooney's comments about building on OpenVMS.
1422     19. Added support for partial matching via the PCRE_PARTIAL option for
1423     pcre_exec() and the \P data escape in pcretest.
1425     20. Extended pcretest with 3 new pattern features:
1427     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1428     write the compiled pattern to the file whose name is "rest-of-line".
1429     This is a straight binary dump of the data, with the saved pointer to
1430     the character tables forced to be NULL. The study data, if any, is
1431     written too. After writing, pcretest reads a new pattern.
1433     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1434     compiled pattern from the given file. There must not be any
1435     occurrences of "<" in the file name (pretty unlikely); if there are,
1436     pcretest will instead treat the initial "<" as a pattern delimiter.
1437     After reading in the pattern, pcretest goes on to read data lines as
1438     usual.
1440     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1441     and 16-bit fields in a compiled pattern, to simulate a pattern that
1442     was compiled on a host of opposite endianness.
1444     21. The pcre-exec() function can now cope with patterns that were compiled on
1445     hosts of opposite endianness, with this restriction:
1447     As for any compiled expression that is saved and used later, the tables
1448     pointer field cannot be preserved; the extra_data field in the arguments
1449     to pcre_exec() should be used to pass in a tables address if a value
1450     other than the default internal tables were used at compile time.
1452     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1453     now diagnosed as an error. Previously, most of the time, a negative number
1454     would have been treated as zero, but if in addition "ovector" was passed as
1455     NULL, a crash could occur.
1457     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1458     new versions from the libtool 1.5 distribution (the last one is a copy of
1459     a file called libtool.m4). This seems to have fixed the need to patch
1460     "configure" to support Darwin 1.3 (which I used to do). However, I still
1461     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1462     workstation).
1464     24. Changed the PCRE licence to be the more standard "BSD" licence.
1467 nigel 73 Version 4.5 01-Dec-03
1468     ---------------------
1470     1. There has been some re-arrangement of the code for the match() function so
1471     that it can be compiled in a version that does not call itself recursively.
1472     Instead, it keeps those local variables that need separate instances for
1473     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1474     needs to "recurse". Keeping track of where control must go is done by means
1475     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1476     hide most of the details from the main code, and operates only if
1477     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1478     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1479     operating.
1481     To make it easier for callers to provide specially tailored get/free
1482     functions for this usage, two new functions, pcre_stack_malloc, and
1483     pcre_stack_free, are used. They are always called in strict stacking order,
1484     and the size of block requested is always the same.
1486     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1487     PCRE has been compiled to use the stack or the heap for recursion. The
1488     -C option of pcretest uses this to show which version is compiled.
1490     A new data escape \S, is added to pcretest; it causes the amounts of store
1491     obtained and freed by both kinds of malloc/free at match time to be added
1492     to the output.
1494     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1495     what's available on my current Linux desktop machine.
1497     3. When matching a UTF-8 string, the test for a valid string at the start has
1498     been extended. If start_offset is not zero, PCRE now checks that it points
1499     to a byte that is the start of a UTF-8 character. If not, it returns
1500     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1501     this is necessary because there may be backward assertions in the pattern.
1502     When matching the same subject several times, it may save resources to use
1503     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1505     4. The code for checking the validity of UTF-8 strings has been tightened so
1506     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1507     containing "overlong sequences".
1509     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1510     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1511     should have been "&", but it just so happened that all the cases this let
1512     through by mistake were picked up later in the function.
1514     6. I had used a variable called "isblank" - this is a C99 function, causing
1515     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1517     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1518     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1519     so the version is shown; (c) stop "make test" echoing "./RunTest".
1521     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1523     9. The prototype for memmove() for systems that don't have it was using
1524     size_t, but the inclusion of the header that defines size_t was later. I've
1525     moved the #includes for the C headers earlier to avoid this.
1527     10. Added some adjustments to the code to make it easier to compiler on certain
1528     special systems:
1530     (a) Some "const" qualifiers were missing.
1531     (b) Added the macro EXPORT before all exported functions; by default this
1532     is defined to be empty.
1533     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1534     that it reads its output file name as an argument instead of writing
1535     to the standard output and assuming this can be redirected.
1537     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1538     class containing characters with values greater than 255, PCRE compilation
1539     went into a loop.
1541     12. A recursive reference to a subpattern that was within another subpattern
1542     that had a minimum quantifier of zero caused PCRE to crash. For example,
1543     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1544     recursion. If the recursively-called subpattern itself had a zero repeat,
1545     that was OK.
1547     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1548     buffer into which it was copied (for escape processing) was still set at
1549     1024, so long lines caused crashes.
1551     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1552     "internal error: code overflow...". This applied to any character class
1553     that was followed by a possessive quantifier.
1555     15. Modified the Makefile to add libpcre.la as a prerequisite for
1556     libpcreposix.la because I was told this is needed for a parallel build to
1557     work.
1559     16. If a pattern that contained .* following optional items at the start was
1560     studied, the wrong optimizing data was generated, leading to matching
1561     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1562     matching string must start with a or b or c. The correct conclusion for
1563     this pattern is that a match can start with any character.
1566 nigel 71 Version 4.4 13-Aug-03
1567     ---------------------
1569     1. In UTF-8 mode, a character class containing characters with values between
1570     127 and 255 was not handled correctly if the compiled pattern was studied.
1571     In fixing this, I have also improved the studying algorithm for such
1572     classes (slightly).
1574     2. Three internal functions had redundant arguments passed to them. Removal
1575     might give a very teeny performance improvement.
1577     3. Documentation bug: the value of the capture_top field in a callout is *one
1578     more than* the number of the hightest numbered captured substring.
1580     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1581     in incorrectly linking with a previously installed version. They now link
1582     explicitly with libpcre.la.
1584     5. configure.in no longer needs to recognize Cygwin specially.
1586     6. A problem in pcre.in for Windows platforms is fixed.
1588     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1589     pcretest, it used to include the size of the study block as part of its
1590     output. Unfortunately, the structure contains a field that has a different
1591     size on different hardware architectures. This meant that the tests that
1592     showed this size failed. As the block is currently always of a fixed size,
1593     this information isn't actually particularly useful in pcretest output, so
1594     I have just removed it.
1596     8. Three pre-processor statements accidentally did not start in column 1.
1597     Sadly, there are *still* compilers around that complain, even though
1598     standard C has not required this for well over a decade. Sigh.
1600     9. In pcretest, the code for checking callouts passed small integers in the
1601     callout_data field, which is a void * field. However, some picky compilers
1602     complained about the casts involved for this on 64-bit systems. Now
1603     pcretest passes the address of the small integer instead, which should get
1604     rid of the warnings.
1606     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1607     both compile and run time, and gives an error if an invalid UTF-8 sequence
1608     is found. There is a option for disabling this check in cases where the
1609     string is known to be correct and/or the maximum performance is wanted.
1611     11. In response to a bug report, I changed one line in Makefile.in from
1613     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1614     to
1615     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1617     to look similar to other lines, but I have no way of telling whether this
1618     is the right thing to do, as I do not use Windows. No doubt I'll get told
1619     if it's wrong...
1622 nigel 69 Version 4.3 21-May-03
1623     ---------------------
1625     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1626     Makefile.
1628     2. Some refactoring to improve the quality of the code:
1630     (i) The utf8_table... variables are now declared "const".
1632     (ii) The code for \cx, which used the "case flipping" table to upper case
1633     lower case letters, now just substracts 32. This is ASCII-specific,
1634     but the whole concept of \cx is ASCII-specific, so it seems
1635     reasonable.
1637     (iii) PCRE was using its character types table to recognize decimal and
1638     hexadecimal digits in the pattern. This is silly, because it handles
1639     only 0-9, a-f, and A-F, but the character types table is locale-
1640     specific, which means strange things might happen. A private
1641     table is now used for this - though it costs 256 bytes, a table is
1642     much faster than multiple explicit tests. Of course, the standard
1643     character types table is still used for matching digits in subject
1644     strings against \d.
1646     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1647     ending in _t are). So I've renamed it as ESC_tee.
1649     3. The first argument for regexec() in the POSIX wrapper should have been
1650     defined as "const".
1652     4. Changed pcretest to use malloc() for its buffers so that they can be
1653     Electric Fenced for debugging.
1655     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1656     to read one or more bytes before the start of the subject string. Often this
1657     had no effect on PCRE's behaviour, but in some circumstances it could
1658     provoke a segmentation fault.
1660     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1661     to try to read one or more bytes before the start of the subject string.
1663     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1664     UTF-8 support could misbehave in various ways if the subject string
1665     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1666     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1667     back over UTF-8 characters.)
1670 nigel 67 Version 4.2 14-Apr-03
1671     ---------------------
1673     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1675     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1676     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1677     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1678     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1679     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1680     and BUILD_EXEEXT
1681     Note: automatic setting of the BUILD variables is not yet working
1682     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1683     compile-time but not at link-time
1684     [LINK]: use for linking executables only
1685     make different versions for Windows and non-Windows
1686     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1687     libraries
1688     [LINK_FOR_BUILD]: new variable
1689     [OBJEXT]: use throughout
1690     [EXEEXT]: use throughout
1691     <winshared>: new target
1692     <wininstall>: new target
1693     <dftables.o>: use native compiler
1694     <dftables>: use native linker
1695     <install>: handle Windows platform correctly
1696     <clean>: ditto
1697     <check>: ditto
1698     copy DLL to top builddir before testing
1700     As part of these changes, -no-undefined was removed again. This was reported
1701     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1702     in any case.
1704     3. Some tidies to get rid of compiler warnings:
1706     . In the match_data structure, match_limit was an unsigned long int, whereas
1707     match_call_count was an int. I've made them both unsigned long ints.
1709     . In pcretest the fact that a const uschar * doesn't automatically cast to
1710     a void * provoked a warning.
1712     . Turning on some more compiler warnings threw up some "shadow" variables
1713     and a few more missing casts.
1715     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1716     option, a class that contained a single character with a value between 128
1717     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1719     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1720     option, a class that contained several characters, but with at least one
1721     whose value was between 128 and 255 caused PCRE to crash.
1724 nigel 65 Version 4.1 12-Mar-03
1725     ---------------------
1726 nigel 63
1727 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1728     needed, and a string in dftables.c that was longer than standard compilers are
1729     required to support.
1731     2. Compiling with Sun's compiler found a few more places where the code could
1732     be tidied up in order to avoid warnings.
1734     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1735     first of these names is deprecated in the latest Autoconf in favour of the name
1736     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1737     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1738     analogy I have changed it to CFLAGS_FOR_BUILD.
1740     4. Added -no-undefined to the linking command in the Makefile, because this is
1741     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1742     linking step for the pcreposix library.
1744     5. PCRE was failing to diagnose the case of two named groups with the same
1745     name.
1747     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1748     literal character that is needed in the subject for a match, and scans along to
1749     ensure that it is present before embarking on the full matching process. This
1750     saves time in cases of nested unlimited repeats that are never going to match.
1751     Problem: the scan can take a lot of time if the subject is very long (e.g.
1752     megabytes), thus penalizing straightforward matches. It is now done only if the
1753     amount of subject to be scanned is less than 1000 bytes.
1755     7. A lesser problem with the same optimization is that it was recording the
1756     first character of an anchored pattern as "needed", thus provoking a search
1757     right along the subject, even when the first match of the pattern was going to
1758     fail. The "needed" character is now not set for anchored patterns, unless it
1759     follows something in the pattern that is of non-fixed length. Thus, it still
1760     fulfils its original purpose of finding quick non-matches in cases of nested
1761     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1764     Version 4.0 17-Feb-03
1765     ---------------------
1767 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1768     extended to the end of string, PCRE compiled incorrect data. This could lead to
1769     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1771     2. Moved to autoconf 2.53 and libtool 1.4.2.
1773     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1774     the special perltest8 script is no longer needed - all the tests can be run
1775     from a single perltest script.
1777     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1778     by \s. It has now been removed in PCRE. This means it isn't recognized as
1779     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1780     class [:space:] *does* include VT, thereby creating a mess.
1782     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1783     space and tab.
1785     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1786     its new features into the main test script, reducing the number of scripts.
1788     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1789     were backward compatible, and made the (?i) apply to the whole pattern, as if
1790     /i were given. Now it behaves more logically, and applies the option setting
1791     only to what follows. PCRE has been changed to follow suit. However, if it
1792     finds options settings right at the start of the pattern, it extracts them into
1793     the global options, as before. Thus, they show up in the info data.
1795     8. Added support for the \Q...\E escape sequence. Characters in between are
1796     treated as literals. This is slightly different from Perl in that $ and @ are
1797     also handled as literals inside the quotes. In Perl, they will cause variable
1798     interpolation. Note the following examples:
1800     Pattern PCRE matches Perl matches
1802     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1803     \Qabc\$xyz\E abc\$xyz abc\$xyz
1804     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1806     For compatibility with Perl, \Q...\E sequences are recognized inside character
1807     classes as well as outside them.
1809     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1810     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1811     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1812     signed/unsigned warnings.
1814     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1815     option for pcretest, so I've replaced it by a simple function that does just
1816     that job.
1818     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1819     "pcregrep -".
1821     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1822     Java package. This provides some syntactic sugar for simple cases of what my
1823     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1824     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1825     item, you can use this simplified notation. Note that only makes sense with
1826     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1827     greediness, whatever the setting of the PCRE_UNGREEDY option.
1829     13. A change of greediness default within a pattern was not taking effect at
1830     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1831     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1832     was abstracted outside.
1834     14. PCRE now supports the \G assertion. It is true when the current matching
1835     position is at the start point of the match. This differs from \A when the
1836     starting offset is non-zero. Used with the /g option of pcretest (or similar
1837     code), it works in the same way as it does for Perl's /g option. If all
1838     alternatives of a regex begin with \G, the expression is anchored to the start
1839     match position, and the "anchored" flag is set in the compiled expression.
1841     15. Some bugs concerning the handling of certain option changes within patterns
1842     have been fixed. These applied to options other than (?ims). For example,
1843     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1844     been the other way round. Some of this was related to change 7 above.
1846     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1847     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1848     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1849     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1851     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1852     mode. Unlike ".", it always matches newline, whatever the setting of
1853     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1854     assertions. Perl allows it, but it doesn't (in general) work because it can't
1855     calculate the length of the lookbehind. At least, that's the case for Perl
1856     5.8.0 - I've been told they are going to document that it doesn't work in
1857     future.
1859     18. Added an error diagnosis for escapes that PCRE does not support: these are
1860     \L, \l, \N, \P, \p, \U, \u, and \X.
1862     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1863     reading past the end of the pattern in cases such as /[abcd/.
1865     20. PCRE was getting more memory than necessary for patterns with classes that
1866     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1868     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1869     compiling PCRE for use with Virtual Pascal.
1871     22. Small fix to the Makefile to make it work properly if the build is done
1872     outside the source tree.
1874     23. Added a new extension: a condition to go with recursion. If a conditional
1875     subpattern starts with (?(R) the "true" branch is used if recursion has
1876     happened, whereas the "false" branch is used only at the top level.
1878     24. When there was a very long string of literal characters (over 255 bytes
1879     without UTF support, over 250 bytes with UTF support), the computation of how
1880     much memory was required could be incorrect, leading to segfaults or other
1881     strange effects.
1883     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1884     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1885     there was a subsequent back reference to those brackets. This meant that, for
1886     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1887     possible to check for precisely this case. All we can do is abandon the
1888     optimization if .* occurs inside capturing brackets when there are any back
1889     references whatsoever. (See below for a better fix that came later.)
1891     26. The handling of the optimization for finding the first character of a
1892     non-anchored pattern, and for finding a character that is required later in the
1893     match were failing in some cases. This didn't break the matching; it just
1894     failed to optimize when it could. The way this is done has been re-implemented.
1896     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1898     28. Added a new feature that provides some of the functionality that Perl
1899     provides with (?{...}). The facility is termed a "callout". The way it is done
1900     in PCRE is for the caller to provide an optional function, by setting
1901     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1902     global variable. By default it is unset, which disables all calling out. To get
1903     the function called, the regex must include (?C) at appropriate points. This
1904     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1905     This provides a means of identifying different callout points. When PCRE
1906     reaches such a point in the regex, if pcre_callout has been set, the external
1907     function is called. It is provided with data in a structure called
1908     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1909     matching continues; if it returns a non-zero value, the match at the current
1910     point fails. However, backtracking will occur if possible. [This was changed
1911     later and other features added - see item 49 below.]
1913     29. pcretest is upgraded to test the callout functionality. It provides a
1914     callout function that displays information. By default, it shows the start of
1915     the match and the current position in the text. There are some new data escapes
1916     to vary what happens:
1918     \C+ in addition, show current contents of captured substrings
1919     \C- do not supply a callout function
1920     \C!n return 1 when callout number n is reached
1921     \C!n!m return 1 when callout number n is reached for the mth time
1923     30. If pcregrep was called with the -l option and just a single file name, it
1924     output "<stdin>" if a match was found, instead of the file name.
1926     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1927     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1928     pcre_exec(). This saves a malloc/free per call. The default value of
1929     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1930     when configuring.
1932     32. The default maximum size of a compiled pattern is 64K. There have been a
1933     few cases of people hitting this limit. The code now uses macros to handle the
1934     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1935     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1936     configuring. Tests 2 and 5 work only with 2-byte links because they output
1937     debugging information about compiled patterns.
1939     33. Internal code re-arrangements:
1941     (a) Moved the debugging function for printing out a compiled regex into
1942     its own source file (printint.c) and used #include to pull it into
1943     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1944     separate copies.
1946     (b) Defined the list of op-code names for debugging as a macro in
1947     internal.h so that it is next to the definition of the opcodes.
1949     (c) Defined a table of op-code lengths for simpler skipping along compiled
1950     code. This is again a macro in internal.h so that it is next to the
1951     definition of the opcodes.
1953     34. Added support for recursive calls to individual subpatterns, along the
1954     lines of Robin Houston's patch (but implemented somewhat differently).
1956     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1957     allow it to read and process whole directories in Win32. This code was
1958     contributed by Lionel Fourquaux; it has not been tested by me.
1960     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1961     used to name a group. Names consist of alphanumerics and underscores, and must
1962     be unique. Back references use the syntax (?P=name) and recursive calls use
1963     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1964     numbers. The function pcre_fullinfo() can be used after compilation to extract
1965     a name/number map. There are three relevant calls:
1967     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1968     PCRE_INFO_NAMECOUNT yields the number of entries
1969     PCRE_INFO_NAMETABLE yields a pointer to the map.
1971     The map is a vector of fixed-size entries. The size of each entry depends on
1972     the length of the longest name used. The first two bytes of each entry are the
1973     group number, most significant byte first. There follows the corresponding
1974     name, zero terminated. The names are in alphabetical order.
1976     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1977     case instead of 255. Making it the same both with and without UTF-8 support
1978     means that the same test output works with both.
1980     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1981     calling malloc() with a zero argument.
1983     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1984     optimization. I've improved things by keeping a bitmap of backreferences with
1985     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1986     fact referenced, the optimization can be applied. It is unlikely that a
1987     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1988     the match to follow \n) will appear inside brackets with a number greater than
1989     31, but if it does, any back reference > 31 suppresses the optimization.
1991     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1992     of disabling numbered capturing parentheses. Any opening parenthesis that is
1993     not followed by ? behaves as if it were followed by ?: but named parentheses
1994     can still be used for capturing (and they will acquire numbers in the usual
1995     way).
1997     41. Redesigned the return codes from the match() function into yes/no/error so
1998     that errors can be passed back from deep inside the nested calls. A malloc
1999     failure while inside a recursive subpattern call now causes the
2000     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2002     42. It is now possible to set a limit on the number of times the match()
2003     function is called in a call to pcre_exec(). This facility makes it possible to
2004     limit the amount of recursion and backtracking, though not in a directly
2005     obvious way, because the match() function is used in a number of different
2006     circumstances. The count starts from zero for each position in the subject
2007     string (for non-anchored patterns). The default limit is, for compatibility, a
2008     large number, namely 10 000 000. You can change this in two ways:
2010     (a) When configuring PCRE before making, you can use --with-match-limit=n
2011     to set a default value for the compiled library.
2013     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2014     a different value is set. See 45 below.
2016     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2018     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2019     of things that can be changed at compile time. The first argument specifies
2020     what is wanted and the second points to where the information is to be placed.
2021     The current list of available information is:
2025     The output is an integer that is set to one if UTF-8 support is available;
2026     otherwise it is set to zero.
2030     The output is an integer that it set to the value of the code that is used for
2031     newline. It is either LF (10) or CR (13).
2035     The output is an integer that contains the number of bytes used for internal
2036     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2040     The output is an integer that contains the threshold above which the POSIX
2041     interface uses malloc() for output vectors. See item 31 above.
2045     The output is an unsigned integer that contains the default limit of the number
2046     of match() calls in a pcre_exec() execution. See 42 above.
2048     44. pcretest has been upgraded by the addition of the -C option. This causes it
2049     to extract all the available output from the new pcre_config() function, and to
2050     output it. The program then exits immediately.
2052     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2053     order to support additional features. One way would have been to define
2054     pcre_exec2() (for example) with extra arguments, but this would not have been
2055     extensible, and would also have required all calls to the original function to
2056     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2057     is used for passing in "extra" data from pcre_study().
2059     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2060     contains the following fields:
2062     flags a bitmap indicating which of the following fields are set
2063     study_data opaque data from pcre_study()
2064     match_limit a way of specifying a limit on match() calls for a specific
2065     call to pcre_exec()
2066     callout_data data for callouts (see 49 below)
2068     The flag bits are also defined in pcre.h, and are
2074     The pcre_study() function now returns one of these new pcre_extra blocks, with
2075     the actual study data pointed to by the study_data field, and the
2076     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2077     before. That is, this change is entirely upwards-compatible and requires no
2078     change to existing code.
2080     If you want to pass in additional data to pcre_exec(), you can either place it
2081     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2082     block.
2084     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2085     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2086     times with different match limits, until it finds the minimum value needed for
2087     pcre_exec() to complete. The value is then output. This can be instructive; for
2088     most simple matches the number is quite small, but for pathological cases it
2089     gets very large very quickly.
2091     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2092     returns the size of the data block pointed to by the study_data field in a
2093     pcre_extra block, that is, the value that was passed as the argument to
2094     pcre_malloc() when PCRE was getting memory in which to place the information
2095     created by pcre_study(). The fourth argument should point to a size_t variable.
2096     pcretest has been extended so that this information is shown after a successful
2097     pcre_study() call when information about the compiled regex is being displayed.
2099     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2100     because what follows is always an absolute path. (Later: it turns out that this
2101     is more than cosmetic for MinGW, because it doesn't like empty path
2102     components.)
2104     49. Some changes have been made to the callout feature (see 28 above):
2106     (i) A callout function now has three choices for what it returns:
2108     0 => success, carry on matching
2109     > 0 => failure at this point, but backtrack if possible
2110     < 0 => serious error, return this value from pcre_exec()
2112     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2113     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2114     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2115     use by callout functions. It will never be used by PCRE itself.
2117     (ii) The pcre_extra structure (see 45 above) has a void * field called
2118     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2119     pcre_callout_block structure has a field of the same name. The contents of
2120     the field passed in the pcre_extra structure are passed to the callout
2121     function in the corresponding field in the callout block. This makes it
2122     easier to use the same callout-containing regex from multiple threads. For
2123     testing, the pcretest program has a new data escape
2125     \C*n pass the number n (may be negative) as callout_data
2127     If the callout function in pcretest receives a non-zero value as
2128     callout_data, it returns that value.
2130     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2131     there were some redundant $(CFLAGS) in commands that are now specified as
2132     $(LINK), which already includes $(CFLAGS).
2134     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2135     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2136     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2137     one-byte characters throughout. Note that case-insensitive matching applies
2138     only to characters whose values are less than 256. PCRE doesn't support the
2139     notion of cases for higher-valued characters.
2141     (i) A character class whose characters are all within 0-255 is handled as
2142     a bit map, and the map is inverted for negative classes. Previously, a
2143     character > 255 always failed to match such a class; however it should
2144     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2146     (ii) A negated character class with a single character < 255 is coded as
2147     "not this character" (OP_NOT). This wasn't working properly when the test
2148     character was multibyte, either singly or repeated.
2150     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2151     mode, for example: \x{100}{2,3}.
2153     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2154     singly or repeated) now correctly test multibyte characters. However,
2155     PCRE doesn't recognize any characters with values greater than 255 as
2156     digits, spaces, or word characters. Such characters always match \D, \S,
2157     and \W, and never match \d, \s, or \w.
2159     (v) Classes may now contain characters and character ranges with values
2160     greater than 255. For example: [ab\x{100}-\x{400}].
2162     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2163     PCRE in UTF-8 mode.
2165     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2166     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2167     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2168     value.)
2170     53. The single man page has become too large. I have therefore split it up into
2171     a number of separate man pages. These also give rise to individual HTML pages;
2172     these are now put in a separate directory, and there is an index.html page that
2173     lists them all. Some hyperlinking between the pages has been installed.
2175     54. Added convenience functions for handling named capturing parentheses.
2177     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2178     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2179     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2180     are faulted.
2182     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2183     calling configure. These values are used when compiling the dftables.c program
2184     which is run to generate the source of the default character tables. They
2185     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2186     you will need to set these values.
2188     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2191     Version 3.9 02-Jan-02
2192 nigel 61 ---------------------
2194     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2196     2. If --disable-static was given, the building process failed when trying to
2197     build pcretest and pcregrep. (For some reason it was using libtool to compile
2198     them, which is not right, as they aren't part of the library.)
2201 nigel 59 Version 3.8 18-Dec-01
2202     ---------------------
2204     1. The experimental UTF-8 code was completely screwed up. It was packing the
2205     bytes in the wrong order. How dumb can you get?
2208 nigel 57 Version 3.7 29-Oct-01
2209     ---------------------
2211     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2212     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2213     this didn't happen under Solaris 8, where I normally test things.
2215 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2216     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2217     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2218     this fix an hour or so after the initial 3.7 release.)
2219 nigel 57
2220 nigel 59
2221 nigel 55 Version 3.6 23-Oct-01
2222     ---------------------
2224     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2225     offsets passed as NULL with zero offset count.
2227     2. The config.guess and config.sub files had not been updated when I moved to
2228     the latest autoconf.
2231 nigel 53 Version 3.5 15-Aug-01
2232     ---------------------
2233 nigel 5
2234 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2235     had been forgotten.
2237     2. By using declared but undefined structures, we can avoid using "void"
2238     definitions in pcre.h while keeping the internal definitions of the structures
2239     private.
2241     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2242     user point of view, this means that both static and shared libraries are built
2243     by default, but this can be individually controlled. More of the work of
2244     handling this static/shared cases is now inside libtool instead of PCRE's make
2245     file.
2247     4. The pcretest utility is now installed along with pcregrep because it is
2248     useful for users (to test regexs) and by doing this, it automatically gets
2249     relinked by libtool. The documentation has been turned into a man page, so
2250     there are now .1, .txt, and .html versions in /doc.
2252     5. Upgrades to pcregrep:
2253     (i) Added long-form option names like gnu grep.
2254     (ii) Added --help to list all options with an explanatory phrase.
2255     (iii) Added -r, --recursive to recurse into sub-directories.
2256     (iv) Added -f, --file to read patterns from a file.
2258     6. pcre_exec() was referring to its "code" argument before testing that
2259     argument for NULL (and giving an error if it was NULL).
2261     7. Upgraded Makefile.in to allow for compiling in a different directory from
2262     the source directory.
2264     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2265     options bits, the pointer it was passed was to an int instead of to an unsigned
2266     long int. This mattered only on 64-bit systems.
2268     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2269     generated) instead of pcre.in, which it its source. Also made the same change
2270     in several of the .c files.
2272     10. A new release of gcc defines printf() as a macro, which broke pcretest
2273     because it had an ifdef in the middle of a string argument for printf(). Fixed
2274     by using separate calls to printf().
2276     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2277     script, to force use of CR or LF instead of \n in the source. On non-Unix
2278     systems, the value can be set in config.h.
2280     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2281     absolute limit. Changed the text of the error message to make this clear, and
2282     likewise updated the man page.
2284     13. The limit of 99 on the number of capturing subpatterns has been removed.
2285     The new limit is 65535, which I hope will not be a "real" limit.
2288 nigel 51 Version 3.4 22-Aug-00
2289     ---------------------
2291     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2293     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2296 nigel 49 Version 3.3 01-Aug-00
2297     ---------------------
2299     1. If an octal character was given, but the value was greater than \377, it
2300     was not getting masked to the least significant bits, as documented. This could
2301     lead to crashes in some systems.
2303     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2304     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2306     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2307     These just pass their arguments on to (pcre_free)(), but they are provided
2308     because some uses of PCRE bind it to non-C systems that can call its functions,
2309     but cannot call free() or pcre_free() directly.
2311     4. Add "make test" as a synonym for "make check". Corrected some comments in
2312     the Makefile.
2314     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2315     Makefile.
2317     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2318     command called pgrep for grepping around the active processes.
2320     7. Added the beginnings of support for UTF-8 character strings.
2322     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2323     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2324     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2325     out for the ar command.)
2328 nigel 47 Version 3.2 12-May-00
2329     ---------------------
2331     This is purely a bug fixing release.
2333     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2334     of ZA. This was just one example of several cases that could provoke this bug,
2335     which was introduced by change 9 of version 2.00. The code for breaking
2336     infinite loops after an iteration that matches an empty string was't working
2337     correctly.
2339     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2340     when matched against abbab (for example). After matching an empty string, it
2341     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2342     caused it to match further down the string than it should.
2344     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2345     was there because it doesn't seem to be needed, and it causes trouble on some
2346     systems, as it is not a Standard C header. It has been removed.
2348     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2349     were reported on the Macintosh. The changes were from
2351     while ((c = *(++ptr)) != 0 && c != '\n');
2352     to
2353     while ((c = *(++ptr)) != 0 && c != '\n') ;
2355     Totally extraordinary, but if that's what it takes...
2357     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2358     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2359     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2360     assumes the way PCRE uses memmove() (always moving upwards).
2362     6. PCRE is being used in one environment where strchr() is not available. There
2363     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2364     faster code anyway.
2367 nigel 45 Version 3.1 09-Feb-00
2368     ---------------------
2370     The only change in this release is the fixing of some bugs in Makefile.in for
2371     the "install" target:
2373     (1) It was failing to install pcreposix.h.
2375     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2378 nigel 43 Version 3.0 01-Feb-00
2379     ---------------------
2380 nigel 41
2381     1. Add support for the /+ modifier to perltest (to output $` like it does in
2382     pcretest).
2384     2. Add support for the /g modifier to perltest.
2386     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2387     matches null strings.
2389     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2390     pattern. Perl treats empty patterns specially - it reuses the most recent
2391     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2392     effect.
2394     5. The POSIX interface was broken in that it was just handing over the POSIX
2395     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2396     required a bigger vector, with some working space on the end. This means that
2397     the POSIX wrapper now has to get and free some memory, and copy the results.
2399 nigel 43 6. Added some simple autoconf support, placing the test data and the
2400     documentation in separate directories, re-organizing some of the
2401     information files, and making it build pcre-config (a GNU standard). Also added
2402     libtool support for building PCRE as a shared library, which is now the
2403     default.
2404 nigel 41
2405 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2406     09 are not valid octal constants. Single digits will be used for minor values
2407     less than 10.
2409     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2410     existing programs that set these in the POSIX interface can use PCRE without
2411     modification.
2413     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2414     return all that pcre_info() returns, plus additional data. The pcre_info()
2415     function is retained for compatibility, but is considered to be obsolete.
2417     10. Added experimental recursion feature (?R) to handle one common case that
2418     Perl 5.6 will be able to do with (?p{...}).
2420     11. Added support for POSIX character classes like [:alpha:], which Perl is
2421     adopting.
2424 nigel 39 Version 2.08 31-Aug-99
2425     ----------------------
2427     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2428     trying to match at the startoffset position, but instead was moving forward to
2429     the next newline as if a previous match had failed.
2431     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2432     and could get into a loop if a null string was matched other than at the start
2433     of the subject.
2435     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2436     be distinguished at compile time, and for completeness also added PCRE_DATE.
2438     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2439     in GnuWin32 environments.
2442 nigel 37 Version 2.07 29-Jul-99
2443     ----------------------
2445     1. The documentation is now supplied in plain text form and HTML as well as in
2446     the form of man page sources.
2448     2. C++ compilers don't like assigning (void *) values to other pointer types.
2449     In particular this affects malloc(). Although there is no problem in Standard
2450     C, I've put in casts to keep C++ compilers happy.
2452     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2453     should be (const char *).
2455     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2456     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2457     However, I haven't made this a standard facility. The documentation doesn't
2458     mention it, and the Makefile doesn't support it.
2460     5. The Makefile now contains an "install" target, with editable destinations at
2461     the top of the file. The pcretest program is not installed.
2463     6. pgrep -V now gives the PCRE version number and date.
2465     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2466     causing the entire string to be ignored, instead of just the last character.
2468     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2469     non-matching string, it can take a very, very long time, even for strings of
2470     quite modest length, because of the nested recursion. PCRE now does better in
2471     some of these cases. It does this by remembering the last required literal
2472     character in the pattern, and pre-searching the subject to ensure it is present
2473     before running the real match. In other words, it applies a heuristic to detect
2474     some types of certain failure quickly, and in the above example, if presented
2475     with a string that has no trailing " it gives "no match" very quickly.
2477     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2478     other alternatives are tried instead.
2481 nigel 35 Version 2.06 09-Jun-99
2482     ----------------------
2484     1. Change pcretest's output for amount of store used to show just the code
2485     space, because the remainder (the data block) varies in size between 32-bit and
2486     64-bit systems.
2488     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2489     start matching at. This allows lookbehinds to work when searching for multiple
2490     occurrences in a string.
2492     3. Added additional options to pcretest for testing multiple occurrences:
2494     /+ outputs the rest of the string that follows a match
2495     /g loops for multiple occurrences, using the new startoffset argument
2496     /G loops for multiple occurrences by passing an incremented pointer
2498     4. PCRE wasn't doing the "first character" optimization for patterns starting
2499     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2500     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2501     the letter 'x'. On long subject strings, this gives a significant speed-up.
2504 nigel 33 Version 2.05 21-Apr-99
2505     ----------------------
2507     1. Changed the type of magic_number from int to long int so that it works
2508     properly on 16-bit systems.
2510     2. Fixed a bug which caused patterns starting with .* not to work correctly
2511     when the subject string contained newline characters. PCRE was assuming
2512     anchoring for such patterns in all cases, which is not correct because .* will
2513     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2514     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2515     must be retried after every newline in the subject.
2518 nigel 31 Version 2.04 18-Feb-99
2519     ----------------------
2521     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2522     computation of the store needed to hold the pattern was incorrect (too large).
2523     If such patterns were nested a few deep, this could multiply and become a real
2524     problem.
2526     2. Added /M option to pcretest to show the memory requirement of a specific
2527     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2529     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2530     compiled in such a way that the backtracking after subsequent failure was
2531     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2532     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2535 nigel 29 Version 2.03 02-Feb-99
2536     ----------------------
2538     1. Fixed typo and small mistake in man page.
2540 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2541     LICENCE file containing the conditions.
2542 nigel 29
2543     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2544     Perl, that is the internal \ allows the delimiter to be included in the
2545     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2546     the final delimiter, add \ to the end of the pattern (to test the error).
2548     4. Added the convenience functions for extracting substrings after a successful
2549     match. Updated pcretest to make it able to test these functions.
2552 nigel 27 Version 2.02 14-Jan-99
2553     ----------------------
2555     1. Initialized the working variables associated with each extraction so that
2556     their saving and restoring doesn't refer to uninitialized store.
2558     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2559     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2560     fix the problem.
2562     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2563     calls, and wasn't printing the correct value for compiling calls. Increased the
2564     default value of LOOPREPEAT, and the number of significant figures in the
2565     times.
2567     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2569     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2570     a building problem on Windows NT with a FAT file system.
2573 nigel 25 Version 2.01 21-Oct-98
2574     ----------------------
2576     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2577     to character tables built by pcre_maketables() in the current locale. If NULL
2578     is passed, the default tables are used.
2581 nigel 23 Version 2.00 24-Sep-98
2582 nigel 21 ----------------------
2584 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2585     it any more.
2587     2. Allow quantification of (?>) groups, and make it work correctly.
2589     3. The first character computation wasn't working for (?>) groups.
2591     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2592     end of the subject) and add 5.005's \z, which really does match only at the
2593     very end of the subject.
2595     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2597     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2598     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2599     localized options. All options to pcre_study() were also removed.
2601     7. Add other new features from 5.005:
2603     $(?<= positive lookbehind
2604     $(?<! negative lookbehind
2605     (?imsx-imsx) added the unsetting capability
2606     such a setting is global if at outer level; local otherwise
2607     (?imsx-imsx:) non-capturing groups with option setting
2608     (?(cond)re|re) conditional pattern matching
2610     A backreference to itself in a repeated group matches the previous
2611     captured string.
2613     8. General tidying up of studying (both automatic and via "study")
2614     consequential on the addition of new assertions.
2616     9. As in 5.005, unlimited repeated groups that could match an empty substring
2617     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2618     runtime if any iteration does actually match an empty substring.
2620     10. Include the RunTest script in the distribution.
2622     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2623     discrepancies, some of which were old and were also with respect to 5.004. They
2624     have now been fixed.
2627     Version 1.09 28-Apr-98
2628     ----------------------
2630 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2631     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2632     program crashes, or just wrong answers. This did not apply to negated classes
2633     containing more than one character, or to minima other than one.
2636 nigel 19 Version 1.08 27-Mar-98
2637     ----------------------
2639     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2641     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2642     latter must appear before anything that relies on it in the pattern.
2645 nigel 17 Version 1.07 16-Feb-98
2646     ----------------------
2648     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2649     repeat of a potentially empty string).
2652 nigel 15 Version 1.06 23-Jan-98
2653     ----------------------
2655     1. Added Markus Oberhumer's little patches for C++.
2657     2. Literal strings longer than 255 characters were broken.
2660 nigel 13 Version 1.05 23-Dec-97
2661     ----------------------
2663     1. Negated character classes containing more than one character were failing if
2664     PCRE_CASELESS was set at run time.
2667 nigel 11 Version 1.04 19-Dec-97
2668     ----------------------
2670     1. Corrected the man page, where some "const" qualifiers had been omitted.
2672     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2673     input syntax.
2675     3. Fixed memory leak which occurred when a regex with back references was
2676     matched with an offsets vector that wasn't big enough. The temporary memory
2677     that is used in this case wasn't being freed if the match failed.
2679     4. Tidied pcretest to ensure it frees memory that it gets.
2681     5. Temporary memory was being obtained in the case where the passed offsets
2682     vector was exactly big enough.
2684     6. Corrected definition of offsetof() from change 5 below.
2686     7. I had screwed up change 6 below and broken the rules for the use of
2687     setjmp(). Now fixed.
2690 nigel 9 Version 1.03 18-Dec-97
2691     ----------------------
2693     1. A erroneous regex with a missing opening parenthesis was correctly
2694     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2695     on some systems.
2697     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2698     it was reported that one broken compiler failed on the former because "code" is
2699     also an independent variable.
2701     3. The erroneous regex a[]b caused an array overrun reference.
2703     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2704     fail on data ending with that character. (It was going on too far, and checking
2705     the next character, typically a binary zero.) This was specific to the
2706     optimized code for single-character negative classes.
2708     5. Added a contributed patch from the TIN world which does the following:
2710     + Add an undef for memmove, in case the the system defines a macro for it.
2712     + Add a definition of offsetof(), in case there isn't one. (I don't know
2713     the reason behind this - offsetof() is part of the ANSI standard - but
2714     it does no harm).
2716     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2717     most of the places where whitespace preceded '#'. I have given up and
2718     allowed the remaining 2 cases to be at the margin.
2720     + Rename some variables in pcre to eliminate shadowing. This seems very
2721     pedantic, but does no harm, of course.
2723     6. Moved the call to setjmp() into its own function, to get rid of warnings
2724     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2726     7. Constructs such as \d{8,} were compiling into the equivalent of
2727 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2728 nigel 9 outcome, but in this particular case used more store than had been allocated,
2729     which caused the bug to be discovered because it threw up an internal error.
2731     8. The debugging code in both pcre and pcretest for outputting the compiled
2732     form of a regex was going wrong in the case of back references followed by
2733     curly-bracketed repeats.
2736 nigel 7 Version 1.02 12-Dec-97
2737     ----------------------
2739     1. Typos in pcre.3 and comments in the source fixed.
2741     2. Applied a contributed patch to get rid of places where it used to remove
2742     'const' from variables, and fixed some signed/unsigned and uninitialized
2743     variable warnings.
2745     3. Added the "runtest" target to Makefile.
2747     4. Set default compiler flag to -O2 rather than just -O.
2750 nigel 5 Version 1.01 19-Nov-97
2751     ----------------------
2753     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2754     like /([ab]*)*/, that is, for classes with more than one character in them.
2756     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2757     as /((?>a*))*/ (a PCRE_EXTRA facility).
2760     Version 1.00 18-Nov-97
2761     ----------------------
2763     1. Added compile-time macros to support systems such as SunOS4 which don't have
2764     memmove() or strerror() but have other things that can be used instead.
2766     2. Arranged that "make clean" removes the executables.
2769 nigel 3 Version 0.99 27-Oct-97
2770     ----------------------
2772     1. Fixed bug in code for optimizing classes with only one character. It was
2773     initializing a 32-byte map regardless, which could cause it to run off the end
2774     of the memory it had got.
2776     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2779     Version 0.98 22-Oct-97
2780     ----------------------
2782     1. Fixed bug in code for handling temporary memory usage when there are more
2783     back references than supplied space in the ovector. This could cause segfaults.
2786     Version 0.97 21-Oct-97
2787     ----------------------
2789     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2791     2. Optimized negated single characters not to use a bit map.
2793     3. Brought error texts together as macro definitions; clarified some of them;
2794     fixed one that was wrong - it said "range out of order" when it meant "invalid
2795     escape sequence".
2797     4. Changed some char * arguments to const char *.
2799     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2801     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2802     pcretest.
2805     Version 0.96 16-Oct-97
2806     ----------------------
2808     1. Added a simple "pgrep" utility to the distribution.
2810     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2811     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2812     where "ddd" means "one or more decimal digits".
2814     3. Fixed serious bug. If a pattern had a back reference, but the call to
2815     pcre_exec() didn't supply a large enough ovector to record the related
2816     identifying subpattern, the match always failed. PCRE now remembers the number
2817     of the largest back reference, and gets some temporary memory in which to save
2818     the offsets during matching if necessary, in order to ensure that
2819     backreferences always work.
2821     4. Increased the compatibility with Perl in a number of ways:
2823     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2824     to request this handling. The option can be set at compile or exec time.
2826     (b) $ matches before a terminating newline by default; an option
2827     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2828     mode). The option can be set at compile or exec time.
2830     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2831     the same as Perl's. If the decimal number it represents is less than 10
2832     or there aren't that many previous left capturing parentheses, an octal
2833     escape is read. Inside a character class, it's always an octal escape,
2834     even if it is a single digit.
2836     (d) An escaped but undefined alphabetic character is taken as a literal,
2837     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2838     escapes.
2840     (e) {0} is now permitted. (The previous item is removed from the compiled
2841     pattern).
2843     5. Changed all the names of code files so that the basic parts are no longer
2844     than 10 characters, and abolished the teeny "globals.c" file.
2846     6. Changed the handling of character classes; they are now done with a 32-byte
2847     bit map always.
2849     7. Added the -d and /D options to pcretest to make it possible to look at the
2850     internals of compilation without having to recompile pcre.
2853     Version 0.95 23-Sep-97
2854     ----------------------
2856     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2857     \x20 at the start of a run of normal characters. These were being treated as
2858     real characters, instead of the source characters being re-checked.
2861     Version 0.94 18-Sep-97
2862     ----------------------
2864     1. The functions are now thread-safe, with the caveat that the global variables
2865     containing pointers to malloc() and free() or alternative functions are the
2866     same for all threads.
2868     2. Get pcre_study() to generate a bitmap of initial characters for non-
2869     anchored patterns when this is possible, and use it if passed to pcre_exec().
2872     Version 0.93 15-Sep-97
2873     ----------------------
2875     1. /(b)|(:+)/ was computing an incorrect first character.
2877     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2878     but not actually doing anything yet.
2880     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2881     as Perl does (e.g. [-az] or [az-]).
2883     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2884     all possible positions.
2886     5. Split up into different modules to avoid including unneeded functions in a
2887     compiled binary. However, compile and exec are still in one module. The "study"
2888     function is split off.
2890     6. The character tables are now in a separate module whose source is generated
2891     by an auxiliary program - but can then be edited by hand if required. There are
2892     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2893     toupper() in the code.
2895     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2896     make them global. Abolish the function for setting them, as the caller can now
2897     set them directly.
2900     Version 0.92 11-Sep-97
2901     ----------------------
2903     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2904     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2906     2. Caseless matching was not working in character classes if the characters in
2907     the pattern were in upper case.
2909     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2911     4. Make PCRE_ANCHORED public and accept as a compile option.
2913     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2914     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2915     pass them.
2917     6. Give an error if bad option bits passed at compile or run time.
2919     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2920     pcretest to cause it to pass that flag.
2922     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2923     options, and the first character, if set.
2925     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2928     Version 0.91 10-Sep-97
2929     ----------------------
2931     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2932     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2934     2. PCRE was looping on encountering an indefinitely repeated back reference to
2935     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2936     Perl does - treats the match as successful.
2938     ****


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