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1 nigel 3 ChangeLog for PCRE
2     ------------------
4 nigel 85 Version 6.4 05-Sep-05
5     ---------------------
7     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
8     "--" to be printed when multiple files were scanned, even when none of the
9     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
10     consider it to be a bug, and have restored the previous behaviour.
12     2. A couple of code tidies to get rid of compiler warnings.
14     3. The pcretest program used to cheat by referring to symbols in the library
15     whose names begin with _pcre_. These are internal symbols that are not
16     really supposed to be visible externally, and in some environments it is
17     possible to suppress them. The cheating is now confined to including
18     certain files from the library's source, which is a bit cleaner.
20     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
21     file's purpose clearer.
23     5. Reorganized pcre_ucp_findchar().
26 nigel 83 Version 6.3 15-Aug-05
27     ---------------------
29     1. The file libpcre.pc.in did not have general read permission in the tarball.
31     2. There were some problems when building without C++ support:
33     (a) If C++ support was not built, "make install" and "make test" still
34     tried to test it.
36     (b) There were problems when the value of CXX was explicitly set. Some
37     changes have been made to try to fix these, and ...
39     (c) --disable-cpp can now be used to explicitly disable C++ support.
41     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
42     backslash in a target when C++ was disabled. This confuses some
43     versions of "make", apparently. Using an intermediate variable solves
44     this. (Same for CPP_LOBJ.)
46     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
47     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
48     necessary on certain architectures.
50     4. Added a setting of -export-symbols-regex to the link command to remove
51     those symbols that are exported in the C sense, but actually are local
52     within the library, and not documented. Their names all begin with
53     "_pcre_". This is not a perfect job, because (a) we have to except some
54     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
55     available (and never for static libraries). I have made a note to try to
56     find a way round (a) in the future.
59 nigel 81 Version 6.2 01-Aug-05
60     ---------------------
62     1. There was no test for integer overflow of quantifier values. A construction
63     such as {1111111111111111} would give undefined results. What is worse, if
64     a minimum quantifier for a parenthesized subpattern overflowed and became
65     negative, the calculation of the memory size went wrong. This could have
66     led to memory overwriting.
68     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
70     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
71     operating environments where this matters.
73     4. Applied Giuseppe Maxia's patch to add additional features for controlling
74     PCRE options from within the C++ wrapper.
76     5. Named capturing subpatterns were not being correctly counted when a pattern
77     was compiled. This caused two problems: (a) If there were more than 100
78     such subpatterns, the calculation of the memory needed for the whole
79     compiled pattern went wrong, leading to an overflow error. (b) Numerical
80     back references of the form \12, where the number was greater than 9, were
81     not recognized as back references, even though there were sufficient
82     previous subpatterns.
84     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
85     versions of gcc, e.g. 2.95.4.
88 nigel 79 Version 6.1 21-Jun-05
89     ---------------------
91     1. There was one reference to the variable "posix" in pcretest.c that was not
92     surrounded by "#if !defined NOPOSIX".
94     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
95     the cross-check on the old pcre_info() function, for the benefit of the
96     cut-down version of PCRE that is currently imported into Exim.
98     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
99     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
100     patterns that start (?i) but I don't think that matters. The use of (?i) is
101     just an example; this all applies to the other options as well.
103     4. Since libtool seems to echo the compile commands it is issuing, the output
104     from "make" can be reduced a bit by putting "@" in front of each libtool
105     compile command.
107     5. Patch from the folks at Google for configure.in to be a bit more thorough
108     in checking for a suitable C++ installation before trying to compile the
109     C++ stuff. This should fix a reported problem when a compiler was present,
110     but no suitable headers.
112     6. The man pages all had just "PCRE" as their title. I have changed them to
113     be the relevant file name. I have also arranged that these names are
114     retained in the file doc/pcre.txt, which is a concatenation in text format
115     of all the man pages except the little individual ones for each function.
117     7. The NON-UNIX-USE file had not been updated for the different set of source
118     files that come with release 6. I also added a few comments about the C++
119     wrapper.
122 nigel 77 Version 6.0 07-Jun-05
123     ---------------------
125     1. Some minor internal re-organization to help with my DFA experiments.
127     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
128     didn't matter for the library itself when fully configured, but did matter
129     when compiling without UCP support, or within Exim, where the ucp files are
130     not imported.
132     3. Refactoring of the library code to split up the various functions into
133     different source modules. The addition of the new DFA matching code (see
134     below) to a single monolithic source would have made it really too
135     unwieldy, quite apart from causing all the code to be include in a
136     statically linked application, when only some functions are used. This is
137     relevant even without the DFA addition now that patterns can be compiled in
138     one application and matched in another.
140     The downside of splitting up is that there have to be some external
141     functions and data tables that are used internally in different modules of
142     the library but which are not part of the API. These have all had their
143     names changed to start with "_pcre_" so that they are unlikely to clash
144     with other external names.
146     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
147     a different (DFA) algorithm. Although it is slower than the original
148     function, it does have some advantages for certain types of matching
149     problem.
151     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
152     including restarting after a partial match.
154     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
155     defined when compiling for Windows was sent to me. I have put it into the
156     code, though I have no means of testing or verifying it.
158     7. Added the pcre_refcount() auxiliary function.
160     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
161     match before or at the first newline in the subject string. In pcretest,
162     the /f option on a pattern can be used to set this.
164     9. A repeated \w when used in UTF-8 mode with characters greater than 256
165     would behave wrongly. This has been present in PCRE since release 4.0.
167     10. A number of changes to the pcregrep command:
169     (a) Refactored how -x works; insert ^(...)$ instead of setting
170     PCRE_ANCHORED and checking the length, in preparation for adding
171     something similar for -w.
173     (b) Added the -w (match as a word) option.
175     (c) Refactored the way lines are read and buffered so as to have more
176     than one at a time available.
178     (d) Implemented a pcregrep test script.
180     (e) Added the -M (multiline match) option. This allows patterns to match
181     over several lines of the subject. The buffering ensures that at least
182     8K, or the rest of the document (whichever is the shorter) is available
183     for matching (and similarly the previous 8K for lookbehind assertions).
185     (f) Changed the --help output so that it now says
187     -w, --word-regex(p)
189     instead of two lines, one with "regex" and the other with "regexp"
190     because that confused at least one person since the short forms are the
191     same. (This required a bit of code, as the output is generated
192     automatically from a table. It wasn't just a text change.)
194     (g) -- can be used to terminate pcregrep options if the next thing isn't an
195     option but starts with a hyphen. Could be a pattern or a path name
196     starting with a hyphen, for instance.
198     (h) "-" can be given as a file name to represent stdin.
200     (i) When file names are being printed, "(standard input)" is used for
201     the standard input, for compatibility with GNU grep. Previously
202     "<stdin>" was used.
204     (j) The option --label=xxx can be used to supply a name to be used for
205     stdin when file names are being printed. There is no short form.
207     (k) Re-factored the options decoding logic because we are going to add
208     two more options that take data. Such options can now be given in four
209     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
211     (l) Added the -A, -B, and -C options for requesting that lines of context
212     around matches be printed.
214     (m) Added the -L option to print the names of files that do not contain
215     any matching lines, that is, the complement of -l.
217     (n) The return code is 2 if any file cannot be opened, but pcregrep does
218     continue to scan other files.
220     (o) The -s option was incorrectly implemented. For compatibility with other
221     greps, it now suppresses the error message for a non-existent or non-
222     accessible file (but not the return code). There is a new option called
223     -q that suppresses the output of matching lines, which was what -s was
224     previously doing.
226     (p) Added --include and --exclude options to specify files for inclusion
227     and exclusion when recursing.
229     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
230     Hopefully, it now does.
232     12. Missing cast in pcre_study().
234     13. Added an "uninstall" target to the makefile.
236     14. Replaced "extern" in the function prototypes in Makefile.in with
237     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
238     world, but is set differently for Windows.
240     15. Added a second compiling function called pcre_compile2(). The only
241     difference is that it has an extra argument, which is a pointer to an
242     integer error code. When there is a compile-time failure, this is set
243     non-zero, in addition to the error test pointer being set to point to an
244     error message. The new argument may be NULL if no error number is required
245     (but then you may as well call pcre_compile(), which is now just a
246     wrapper). This facility is provided because some applications need a
247     numeric error indication, but it has also enabled me to tidy up the way
248     compile-time errors are handled in the POSIX wrapper.
250     16. Added VPATH=.libs to the makefile; this should help when building with one
251     prefix path and installing with another. (Or so I'm told by someone who
252     knows more about this stuff than I do.)
254     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
255     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
256     match everything, including newlines. This is not POSIX-compatible, but
257     somebody wanted the feature. From pcretest it can be activated by using
258     both the P and the s flags.
260     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
262     19. libpcre.pc was being incorrectly installed as executable.
264     20. A couple of places in pcretest check for end-of-line by looking for '\n';
265     it now also looks for '\r' so that it will work unmodified on Windows.
267     21. Added Google's contributed C++ wrapper to the distribution.
269     22. Added some untidy missing memory free() calls in pcretest, to keep
270     Electric Fence happy when testing.
274 nigel 75 Version 5.0 13-Sep-04
275     ---------------------
277     1. Internal change: literal characters are no longer packed up into items
278     containing multiple characters in a single byte-string. Each character
279     is now matched using a separate opcode. However, there may be more than one
280     byte in the character in UTF-8 mode.
282     2. The pcre_callout_block structure has two new fields: pattern_position and
283     next_item_length. These contain the offset in the pattern to the next match
284     item, and its length, respectively.
286     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
287     insertion of callouts before each pattern item. Added the /C option to
288     pcretest to make use of this.
290     4. On the advice of a Windows user, the lines
292     #if defined(_WIN32) || defined(WIN32)
293     _setmode( _fileno( stdout ), 0x8000 );
294     #endif /* defined(_WIN32) || defined(WIN32) */
296     have been added to the source of pcretest. This apparently does useful
297     magic in relation to line terminators.
299     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
300     for the benefit of those environments where the "b" makes a difference.
302     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
303     to know about it. I have put a hack into configure.in that adds in code
304     to set GCC=yes if CC=icc. This seems to end up at a point in the
305     generated configure script that is early enough to affect the setting of
306     compiler options, which is what is needed, but I have no means of testing
307     whether it really works. (The user who reported this had patched the
308     generated configure script, which of course I cannot do.)
310     LATER: After change 22 below (new libtool files), the configure script
311     seems to know about icc (and also ecc). Therefore, I have commented out
312     this hack in configure.in.
314     7. Added support for pkg-config (2 patches were sent in).
316     8. Negated POSIX character classes that used a combination of internal tables
317     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
318     [[:^ascii]]. Typically, they would match almost any characters. The other
319     POSIX classes were not broken in this way.
321     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
322     to find the match, as PCRE was deluded into thinking that the match had to
323     start at the start point or following a newline. The same bug applied to
324     patterns with negative forward assertions or any backward assertions
325     preceding ".*" at the start, unless the pattern required a fixed first
326     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
328     10. In UTF-8 mode, when moving forwards in the subject after a failed match
329     starting at the last subject character, bytes beyond the end of the subject
330     string were read.
332     11. Renamed the variable "class" as "classbits" to make life easier for C++
333     users. (Previously there was a macro definition, but it apparently wasn't
334     enough.)
336     12. Added the new field "tables" to the extra data so that tables can be passed
337     in at exec time, or the internal tables can be re-selected. This allows
338     a compiled regex to be saved and re-used at a later time by a different
339     program that might have everything at different addresses.
341     13. Modified the pcre-config script so that, when run on Solaris, it shows a
342     -R library as well as a -L library.
344     14. The debugging options of pcretest (-d on the command line or D on a
345     pattern) showed incorrect output for anything following an extended class
346     that contained multibyte characters and which was followed by a quantifier.
348     15. Added optional support for general category Unicode character properties
349     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
350     support. It adds about 90K to the size of the library. The meanings of the
351     inbuilt class escapes such as \d and \s have NOT been changed.
353     16. Updated pcredemo.c to include calls to free() to release the memory for the
354     compiled pattern.
356     17. The generated file chartables.c was being created in the source directory
357     instead of in the building directory. This caused the build to fail if the
358     source directory was different from the building directory, and was
359     read-only.
361     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
362     file. No doubt somebody will tell me if they don't make sense... Also added
363     Dan Mooney's comments about building on OpenVMS.
365     19. Added support for partial matching via the PCRE_PARTIAL option for
366     pcre_exec() and the \P data escape in pcretest.
368     20. Extended pcretest with 3 new pattern features:
370     (i) A pattern option of the form ">rest-of-line" causes pcretest to
371     write the compiled pattern to the file whose name is "rest-of-line".
372     This is a straight binary dump of the data, with the saved pointer to
373     the character tables forced to be NULL. The study data, if any, is
374     written too. After writing, pcretest reads a new pattern.
376     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
377     compiled pattern from the given file. There must not be any
378     occurrences of "<" in the file name (pretty unlikely); if there are,
379     pcretest will instead treat the initial "<" as a pattern delimiter.
380     After reading in the pattern, pcretest goes on to read data lines as
381     usual.
383     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
384     and 16-bit fields in a compiled pattern, to simulate a pattern that
385     was compiled on a host of opposite endianness.
387     21. The pcre-exec() function can now cope with patterns that were compiled on
388     hosts of opposite endianness, with this restriction:
390     As for any compiled expression that is saved and used later, the tables
391     pointer field cannot be preserved; the extra_data field in the arguments
392     to pcre_exec() should be used to pass in a tables address if a value
393     other than the default internal tables were used at compile time.
395     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
396     now diagnosed as an error. Previously, most of the time, a negative number
397     would have been treated as zero, but if in addition "ovector" was passed as
398     NULL, a crash could occur.
400     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
401     new versions from the libtool 1.5 distribution (the last one is a copy of
402     a file called libtool.m4). This seems to have fixed the need to patch
403     "configure" to support Darwin 1.3 (which I used to do). However, I still
404     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
405     workstation).
407     24. Changed the PCRE licence to be the more standard "BSD" licence.
410 nigel 73 Version 4.5 01-Dec-03
411     ---------------------
413     1. There has been some re-arrangement of the code for the match() function so
414     that it can be compiled in a version that does not call itself recursively.
415     Instead, it keeps those local variables that need separate instances for
416     each "recursion" in a frame on the heap, and gets/frees frames whenever it
417     needs to "recurse". Keeping track of where control must go is done by means
418     of setjmp/longjmp. The whole thing is implemented by a set of macros that
419     hide most of the details from the main code, and operates only if
420     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
421     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
422     operating.
424     To make it easier for callers to provide specially tailored get/free
425     functions for this usage, two new functions, pcre_stack_malloc, and
426     pcre_stack_free, are used. They are always called in strict stacking order,
427     and the size of block requested is always the same.
429     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
430     PCRE has been compiled to use the stack or the heap for recursion. The
431     -C option of pcretest uses this to show which version is compiled.
433     A new data escape \S, is added to pcretest; it causes the amounts of store
434     obtained and freed by both kinds of malloc/free at match time to be added
435     to the output.
437     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
438     what's available on my current Linux desktop machine.
440     3. When matching a UTF-8 string, the test for a valid string at the start has
441     been extended. If start_offset is not zero, PCRE now checks that it points
442     to a byte that is the start of a UTF-8 character. If not, it returns
443     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
444     this is necessary because there may be backward assertions in the pattern.
445     When matching the same subject several times, it may save resources to use
446     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
448     4. The code for checking the validity of UTF-8 strings has been tightened so
449     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
450     containing "overlong sequences".
452     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
453     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
454     should have been "&", but it just so happened that all the cases this let
455     through by mistake were picked up later in the function.
457     6. I had used a variable called "isblank" - this is a C99 function, causing
458     some compilers to warn. To avoid this, I renamed it (as "blankclass").
460     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
461     prompting; (b) run "./pcretest /dev/null" at the start of the test script
462     so the version is shown; (c) stop "make test" echoing "./RunTest".
464     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
466     9. The prototype for memmove() for systems that don't have it was using
467     size_t, but the inclusion of the header that defines size_t was later. I've
468     moved the #includes for the C headers earlier to avoid this.
470     10. Added some adjustments to the code to make it easier to compiler on certain
471     special systems:
473     (a) Some "const" qualifiers were missing.
474     (b) Added the macro EXPORT before all exported functions; by default this
475     is defined to be empty.
476     (c) Changed the dftables auxiliary program (that builds chartables.c) so
477     that it reads its output file name as an argument instead of writing
478     to the standard output and assuming this can be redirected.
480     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
481     class containing characters with values greater than 255, PCRE compilation
482     went into a loop.
484     12. A recursive reference to a subpattern that was within another subpattern
485     that had a minimum quantifier of zero caused PCRE to crash. For example,
486     (x(y(?2))z)? provoked this bug with a subject that got as far as the
487     recursion. If the recursively-called subpattern itself had a zero repeat,
488     that was OK.
490     13. In pcretest, the buffer for reading a data line was set at 30K, but the
491     buffer into which it was copied (for escape processing) was still set at
492     1024, so long lines caused crashes.
494     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
495     "internal error: code overflow...". This applied to any character class
496     that was followed by a possessive quantifier.
498     15. Modified the Makefile to add libpcre.la as a prerequisite for
499     libpcreposix.la because I was told this is needed for a parallel build to
500     work.
502     16. If a pattern that contained .* following optional items at the start was
503     studied, the wrong optimizing data was generated, leading to matching
504     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
505     matching string must start with a or b or c. The correct conclusion for
506     this pattern is that a match can start with any character.
509 nigel 71 Version 4.4 13-Aug-03
510     ---------------------
512     1. In UTF-8 mode, a character class containing characters with values between
513     127 and 255 was not handled correctly if the compiled pattern was studied.
514     In fixing this, I have also improved the studying algorithm for such
515     classes (slightly).
517     2. Three internal functions had redundant arguments passed to them. Removal
518     might give a very teeny performance improvement.
520     3. Documentation bug: the value of the capture_top field in a callout is *one
521     more than* the number of the hightest numbered captured substring.
523     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
524     in incorrectly linking with a previously installed version. They now link
525     explicitly with libpcre.la.
527     5. configure.in no longer needs to recognize Cygwin specially.
529     6. A problem in pcre.in for Windows platforms is fixed.
531     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
532     pcretest, it used to include the size of the study block as part of its
533     output. Unfortunately, the structure contains a field that has a different
534     size on different hardware architectures. This meant that the tests that
535     showed this size failed. As the block is currently always of a fixed size,
536     this information isn't actually particularly useful in pcretest output, so
537     I have just removed it.
539     8. Three pre-processor statements accidentally did not start in column 1.
540     Sadly, there are *still* compilers around that complain, even though
541     standard C has not required this for well over a decade. Sigh.
543     9. In pcretest, the code for checking callouts passed small integers in the
544     callout_data field, which is a void * field. However, some picky compilers
545     complained about the casts involved for this on 64-bit systems. Now
546     pcretest passes the address of the small integer instead, which should get
547     rid of the warnings.
549     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
550     both compile and run time, and gives an error if an invalid UTF-8 sequence
551     is found. There is a option for disabling this check in cases where the
552     string is known to be correct and/or the maximum performance is wanted.
554     11. In response to a bug report, I changed one line in Makefile.in from
556     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
557     to
558     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
560     to look similar to other lines, but I have no way of telling whether this
561     is the right thing to do, as I do not use Windows. No doubt I'll get told
562     if it's wrong...
565 nigel 69 Version 4.3 21-May-03
566     ---------------------
568     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
569     Makefile.
571     2. Some refactoring to improve the quality of the code:
573     (i) The utf8_table... variables are now declared "const".
575     (ii) The code for \cx, which used the "case flipping" table to upper case
576     lower case letters, now just substracts 32. This is ASCII-specific,
577     but the whole concept of \cx is ASCII-specific, so it seems
578     reasonable.
580     (iii) PCRE was using its character types table to recognize decimal and
581     hexadecimal digits in the pattern. This is silly, because it handles
582     only 0-9, a-f, and A-F, but the character types table is locale-
583     specific, which means strange things might happen. A private
584     table is now used for this - though it costs 256 bytes, a table is
585     much faster than multiple explicit tests. Of course, the standard
586     character types table is still used for matching digits in subject
587     strings against \d.
589     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
590     ending in _t are). So I've renamed it as ESC_tee.
592     3. The first argument for regexec() in the POSIX wrapper should have been
593     defined as "const".
595     4. Changed pcretest to use malloc() for its buffers so that they can be
596     Electric Fenced for debugging.
598     5. There were several places in the code where, in UTF-8 mode, PCRE would try
599     to read one or more bytes before the start of the subject string. Often this
600     had no effect on PCRE's behaviour, but in some circumstances it could
601     provoke a segmentation fault.
603     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
604     to try to read one or more bytes before the start of the subject string.
606     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
607     UTF-8 support could misbehave in various ways if the subject string
608     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
609     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
610     back over UTF-8 characters.)
613 nigel 67 Version 4.2 14-Apr-03
614     ---------------------
616     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
618     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
619     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
620     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
621     [WIN_PREFIX]: new variable, "cyg" for Cygwin
622     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
623     and BUILD_EXEEXT
624     Note: automatic setting of the BUILD variables is not yet working
625     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
626     compile-time but not at link-time
627     [LINK]: use for linking executables only
628     make different versions for Windows and non-Windows
629     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
630     libraries
631     [LINK_FOR_BUILD]: new variable
632     [OBJEXT]: use throughout
633     [EXEEXT]: use throughout
634     <winshared>: new target
635     <wininstall>: new target
636     <dftables.o>: use native compiler
637     <dftables>: use native linker
638     <install>: handle Windows platform correctly
639     <clean>: ditto
640     <check>: ditto
641     copy DLL to top builddir before testing
643     As part of these changes, -no-undefined was removed again. This was reported
644     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
645     in any case.
647     3. Some tidies to get rid of compiler warnings:
649     . In the match_data structure, match_limit was an unsigned long int, whereas
650     match_call_count was an int. I've made them both unsigned long ints.
652     . In pcretest the fact that a const uschar * doesn't automatically cast to
653     a void * provoked a warning.
655     . Turning on some more compiler warnings threw up some "shadow" variables
656     and a few more missing casts.
658     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
659     option, a class that contained a single character with a value between 128
660     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
662     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
663     option, a class that contained several characters, but with at least one
664     whose value was between 128 and 255 caused PCRE to crash.
667 nigel 65 Version 4.1 12-Mar-03
668     ---------------------
669 nigel 63
670 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
671     needed, and a string in dftables.c that was longer than standard compilers are
672     required to support.
674     2. Compiling with Sun's compiler found a few more places where the code could
675     be tidied up in order to avoid warnings.
677     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
678     first of these names is deprecated in the latest Autoconf in favour of the name
679     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
680     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
681     analogy I have changed it to CFLAGS_FOR_BUILD.
683     4. Added -no-undefined to the linking command in the Makefile, because this is
684     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
685     linking step for the pcreposix library.
687     5. PCRE was failing to diagnose the case of two named groups with the same
688     name.
690     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
691     literal character that is needed in the subject for a match, and scans along to
692     ensure that it is present before embarking on the full matching process. This
693     saves time in cases of nested unlimited repeats that are never going to match.
694     Problem: the scan can take a lot of time if the subject is very long (e.g.
695     megabytes), thus penalizing straightforward matches. It is now done only if the
696     amount of subject to be scanned is less than 1000 bytes.
698     7. A lesser problem with the same optimization is that it was recording the
699     first character of an anchored pattern as "needed", thus provoking a search
700     right along the subject, even when the first match of the pattern was going to
701     fail. The "needed" character is now not set for anchored patterns, unless it
702     follows something in the pattern that is of non-fixed length. Thus, it still
703     fulfils its original purpose of finding quick non-matches in cases of nested
704     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
707     Version 4.0 17-Feb-03
708     ---------------------
710 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
711     extended to the end of string, PCRE compiled incorrect data. This could lead to
712     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
714     2. Moved to autoconf 2.53 and libtool 1.4.2.
716     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
717     the special perltest8 script is no longer needed - all the tests can be run
718     from a single perltest script.
720     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
721     by \s. It has now been removed in PCRE. This means it isn't recognized as
722     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
723     class [:space:] *does* include VT, thereby creating a mess.
725     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
726     space and tab.
728     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
729     its new features into the main test script, reducing the number of scripts.
731     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
732     were backward compatible, and made the (?i) apply to the whole pattern, as if
733     /i were given. Now it behaves more logically, and applies the option setting
734     only to what follows. PCRE has been changed to follow suit. However, if it
735     finds options settings right at the start of the pattern, it extracts them into
736     the global options, as before. Thus, they show up in the info data.
738     8. Added support for the \Q...\E escape sequence. Characters in between are
739     treated as literals. This is slightly different from Perl in that $ and @ are
740     also handled as literals inside the quotes. In Perl, they will cause variable
741     interpolation. Note the following examples:
743     Pattern PCRE matches Perl matches
745     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
746     \Qabc\$xyz\E abc\$xyz abc\$xyz
747     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
749     For compatibility with Perl, \Q...\E sequences are recognized inside character
750     classes as well as outside them.
752     9. Re-organized 3 code statements in pcretest to avoid "overflow in
753     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
754     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
755     signed/unsigned warnings.
757     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
758     option for pcretest, so I've replaced it by a simple function that does just
759     that job.
761     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
762     "pcregrep -".
764     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
765     Java package. This provides some syntactic sugar for simple cases of what my
766     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
767     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
768     item, you can use this simplified notation. Note that only makes sense with
769     greedy quantifiers. Consequently, the use of the possessive quantifier forces
770     greediness, whatever the setting of the PCRE_UNGREEDY option.
772     13. A change of greediness default within a pattern was not taking effect at
773     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
774     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
775     was abstracted outside.
777     14. PCRE now supports the \G assertion. It is true when the current matching
778     position is at the start point of the match. This differs from \A when the
779     starting offset is non-zero. Used with the /g option of pcretest (or similar
780     code), it works in the same way as it does for Perl's /g option. If all
781     alternatives of a regex begin with \G, the expression is anchored to the start
782     match position, and the "anchored" flag is set in the compiled expression.
784     15. Some bugs concerning the handling of certain option changes within patterns
785     have been fixed. These applied to options other than (?ims). For example,
786     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
787     been the other way round. Some of this was related to change 7 above.
789     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
790     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
791     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
792     POSIX classes only within a class (e.g. /[[:alpha:]]/).
794     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
795     mode. Unlike ".", it always matches newline, whatever the setting of
796     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
797     assertions. Perl allows it, but it doesn't (in general) work because it can't
798     calculate the length of the lookbehind. At least, that's the case for Perl
799     5.8.0 - I've been told they are going to document that it doesn't work in
800     future.
802     18. Added an error diagnosis for escapes that PCRE does not support: these are
803     \L, \l, \N, \P, \p, \U, \u, and \X.
805     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
806     reading past the end of the pattern in cases such as /[abcd/.
808     20. PCRE was getting more memory than necessary for patterns with classes that
809     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
811     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
812     compiling PCRE for use with Virtual Pascal.
814     22. Small fix to the Makefile to make it work properly if the build is done
815     outside the source tree.
817     23. Added a new extension: a condition to go with recursion. If a conditional
818     subpattern starts with (?(R) the "true" branch is used if recursion has
819     happened, whereas the "false" branch is used only at the top level.
821     24. When there was a very long string of literal characters (over 255 bytes
822     without UTF support, over 250 bytes with UTF support), the computation of how
823     much memory was required could be incorrect, leading to segfaults or other
824     strange effects.
826     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
827     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
828     there was a subsequent back reference to those brackets. This meant that, for
829     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
830     possible to check for precisely this case. All we can do is abandon the
831     optimization if .* occurs inside capturing brackets when there are any back
832     references whatsoever. (See below for a better fix that came later.)
834     26. The handling of the optimization for finding the first character of a
835     non-anchored pattern, and for finding a character that is required later in the
836     match were failing in some cases. This didn't break the matching; it just
837     failed to optimize when it could. The way this is done has been re-implemented.
839     27. Fixed typo in error message for invalid (?R item (it said "(?p").
841     28. Added a new feature that provides some of the functionality that Perl
842     provides with (?{...}). The facility is termed a "callout". The way it is done
843     in PCRE is for the caller to provide an optional function, by setting
844     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
845     global variable. By default it is unset, which disables all calling out. To get
846     the function called, the regex must include (?C) at appropriate points. This
847     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
848     This provides a means of identifying different callout points. When PCRE
849     reaches such a point in the regex, if pcre_callout has been set, the external
850     function is called. It is provided with data in a structure called
851     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
852     matching continues; if it returns a non-zero value, the match at the current
853     point fails. However, backtracking will occur if possible. [This was changed
854     later and other features added - see item 49 below.]
856     29. pcretest is upgraded to test the callout functionality. It provides a
857     callout function that displays information. By default, it shows the start of
858     the match and the current position in the text. There are some new data escapes
859     to vary what happens:
861     \C+ in addition, show current contents of captured substrings
862     \C- do not supply a callout function
863     \C!n return 1 when callout number n is reached
864     \C!n!m return 1 when callout number n is reached for the mth time
866     30. If pcregrep was called with the -l option and just a single file name, it
867     output "<stdin>" if a match was found, instead of the file name.
869     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
870     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
871     pcre_exec(). This saves a malloc/free per call. The default value of
872     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
873     when configuring.
875     32. The default maximum size of a compiled pattern is 64K. There have been a
876     few cases of people hitting this limit. The code now uses macros to handle the
877     storing of links as offsets within the compiled pattern. It defaults to 2-byte
878     links, but this can be changed to 3 or 4 bytes by --with-link-size when
879     configuring. Tests 2 and 5 work only with 2-byte links because they output
880     debugging information about compiled patterns.
882     33. Internal code re-arrangements:
884     (a) Moved the debugging function for printing out a compiled regex into
885     its own source file (printint.c) and used #include to pull it into
886     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
887     separate copies.
889     (b) Defined the list of op-code names for debugging as a macro in
890     internal.h so that it is next to the definition of the opcodes.
892     (c) Defined a table of op-code lengths for simpler skipping along compiled
893     code. This is again a macro in internal.h so that it is next to the
894     definition of the opcodes.
896     34. Added support for recursive calls to individual subpatterns, along the
897     lines of Robin Houston's patch (but implemented somewhat differently).
899     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
900     allow it to read and process whole directories in Win32. This code was
901     contributed by Lionel Fourquaux; it has not been tested by me.
903     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
904     used to name a group. Names consist of alphanumerics and underscores, and must
905     be unique. Back references use the syntax (?P=name) and recursive calls use
906     (?P>name) which is a PCRE extension to the Python extension. Groups still have
907     numbers. The function pcre_fullinfo() can be used after compilation to extract
908     a name/number map. There are three relevant calls:
910     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
911     PCRE_INFO_NAMECOUNT yields the number of entries
912     PCRE_INFO_NAMETABLE yields a pointer to the map.
914     The map is a vector of fixed-size entries. The size of each entry depends on
915     the length of the longest name used. The first two bytes of each entry are the
916     group number, most significant byte first. There follows the corresponding
917     name, zero terminated. The names are in alphabetical order.
919     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
920     case instead of 255. Making it the same both with and without UTF-8 support
921     means that the same test output works with both.
923     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
924     calling malloc() with a zero argument.
926     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
927     optimization. I've improved things by keeping a bitmap of backreferences with
928     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
929     fact referenced, the optimization can be applied. It is unlikely that a
930     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
931     the match to follow \n) will appear inside brackets with a number greater than
932     31, but if it does, any back reference > 31 suppresses the optimization.
934     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
935     of disabling numbered capturing parentheses. Any opening parenthesis that is
936     not followed by ? behaves as if it were followed by ?: but named parentheses
937     can still be used for capturing (and they will acquire numbers in the usual
938     way).
940     41. Redesigned the return codes from the match() function into yes/no/error so
941     that errors can be passed back from deep inside the nested calls. A malloc
942     failure while inside a recursive subpattern call now causes the
943     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
945     42. It is now possible to set a limit on the number of times the match()
946     function is called in a call to pcre_exec(). This facility makes it possible to
947     limit the amount of recursion and backtracking, though not in a directly
948     obvious way, because the match() function is used in a number of different
949     circumstances. The count starts from zero for each position in the subject
950     string (for non-anchored patterns). The default limit is, for compatibility, a
951     large number, namely 10 000 000. You can change this in two ways:
953     (a) When configuring PCRE before making, you can use --with-match-limit=n
954     to set a default value for the compiled library.
956     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
957     a different value is set. See 45 below.
959     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
961     43. Added a new function pcre_config(int, void *) to enable run-time extraction
962     of things that can be changed at compile time. The first argument specifies
963     what is wanted and the second points to where the information is to be placed.
964     The current list of available information is:
968     The output is an integer that is set to one if UTF-8 support is available;
969     otherwise it is set to zero.
973     The output is an integer that it set to the value of the code that is used for
974     newline. It is either LF (10) or CR (13).
978     The output is an integer that contains the number of bytes used for internal
979     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
983     The output is an integer that contains the threshold above which the POSIX
984     interface uses malloc() for output vectors. See item 31 above.
988     The output is an unsigned integer that contains the default limit of the number
989     of match() calls in a pcre_exec() execution. See 42 above.
991     44. pcretest has been upgraded by the addition of the -C option. This causes it
992     to extract all the available output from the new pcre_config() function, and to
993     output it. The program then exits immediately.
995     45. A need has arisen to pass over additional data with calls to pcre_exec() in
996     order to support additional features. One way would have been to define
997     pcre_exec2() (for example) with extra arguments, but this would not have been
998     extensible, and would also have required all calls to the original function to
999     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1000     is used for passing in "extra" data from pcre_study().
1002     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1003     contains the following fields:
1005     flags a bitmap indicating which of the following fields are set
1006     study_data opaque data from pcre_study()
1007     match_limit a way of specifying a limit on match() calls for a specific
1008     call to pcre_exec()
1009     callout_data data for callouts (see 49 below)
1011     The flag bits are also defined in pcre.h, and are
1017     The pcre_study() function now returns one of these new pcre_extra blocks, with
1018     the actual study data pointed to by the study_data field, and the
1019     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1020     before. That is, this change is entirely upwards-compatible and requires no
1021     change to existing code.
1023     If you want to pass in additional data to pcre_exec(), you can either place it
1024     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1025     block.
1027     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1028     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1029     times with different match limits, until it finds the minimum value needed for
1030     pcre_exec() to complete. The value is then output. This can be instructive; for
1031     most simple matches the number is quite small, but for pathological cases it
1032     gets very large very quickly.
1034     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1035     returns the size of the data block pointed to by the study_data field in a
1036     pcre_extra block, that is, the value that was passed as the argument to
1037     pcre_malloc() when PCRE was getting memory in which to place the information
1038     created by pcre_study(). The fourth argument should point to a size_t variable.
1039     pcretest has been extended so that this information is shown after a successful
1040     pcre_study() call when information about the compiled regex is being displayed.
1042     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1043     because what follows is always an absolute path. (Later: it turns out that this
1044     is more than cosmetic for MinGW, because it doesn't like empty path
1045     components.)
1047     49. Some changes have been made to the callout feature (see 28 above):
1049     (i) A callout function now has three choices for what it returns:
1051     0 => success, carry on matching
1052     > 0 => failure at this point, but backtrack if possible
1053     < 0 => serious error, return this value from pcre_exec()
1055     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1056     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1057     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1058     use by callout functions. It will never be used by PCRE itself.
1060     (ii) The pcre_extra structure (see 45 above) has a void * field called
1061     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1062     pcre_callout_block structure has a field of the same name. The contents of
1063     the field passed in the pcre_extra structure are passed to the callout
1064     function in the corresponding field in the callout block. This makes it
1065     easier to use the same callout-containing regex from multiple threads. For
1066     testing, the pcretest program has a new data escape
1068     \C*n pass the number n (may be negative) as callout_data
1070     If the callout function in pcretest receives a non-zero value as
1071     callout_data, it returns that value.
1073     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1074     there were some redundant $(CFLAGS) in commands that are now specified as
1075     $(LINK), which already includes $(CFLAGS).
1077     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1078     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1079     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1080     one-byte characters throughout. Note that case-insensitive matching applies
1081     only to characters whose values are less than 256. PCRE doesn't support the
1082     notion of cases for higher-valued characters.
1084     (i) A character class whose characters are all within 0-255 is handled as
1085     a bit map, and the map is inverted for negative classes. Previously, a
1086     character > 255 always failed to match such a class; however it should
1087     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1089     (ii) A negated character class with a single character < 255 is coded as
1090     "not this character" (OP_NOT). This wasn't working properly when the test
1091     character was multibyte, either singly or repeated.
1093     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1094     mode, for example: \x{100}{2,3}.
1096     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1097     singly or repeated) now correctly test multibyte characters. However,
1098     PCRE doesn't recognize any characters with values greater than 255 as
1099     digits, spaces, or word characters. Such characters always match \D, \S,
1100     and \W, and never match \d, \s, or \w.
1102     (v) Classes may now contain characters and character ranges with values
1103     greater than 255. For example: [ab\x{100}-\x{400}].
1105     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1106     PCRE in UTF-8 mode.
1108     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1109     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1110     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1111     value.)
1113     53. The single man page has become too large. I have therefore split it up into
1114     a number of separate man pages. These also give rise to individual HTML pages;
1115     these are now put in a separate directory, and there is an index.html page that
1116     lists them all. Some hyperlinking between the pages has been installed.
1118     54. Added convenience functions for handling named capturing parentheses.
1120     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1121     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1122     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1123     are faulted.
1125     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1126     calling configure. These values are used when compiling the dftables.c program
1127     which is run to generate the source of the default character tables. They
1128     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1129     you will need to set these values.
1131     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1134     Version 3.9 02-Jan-02
1135 nigel 61 ---------------------
1137     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1139     2. If --disable-static was given, the building process failed when trying to
1140     build pcretest and pcregrep. (For some reason it was using libtool to compile
1141     them, which is not right, as they aren't part of the library.)
1144 nigel 59 Version 3.8 18-Dec-01
1145     ---------------------
1147     1. The experimental UTF-8 code was completely screwed up. It was packing the
1148     bytes in the wrong order. How dumb can you get?
1151 nigel 57 Version 3.7 29-Oct-01
1152     ---------------------
1154     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1155     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1156     this didn't happen under Solaris 8, where I normally test things.
1158 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1159     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1160     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1161     this fix an hour or so after the initial 3.7 release.)
1162 nigel 57
1163 nigel 59
1164 nigel 55 Version 3.6 23-Oct-01
1165     ---------------------
1167     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1168     offsets passed as NULL with zero offset count.
1170     2. The config.guess and config.sub files had not been updated when I moved to
1171     the latest autoconf.
1174 nigel 53 Version 3.5 15-Aug-01
1175     ---------------------
1176 nigel 5
1177 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1178     had been forgotten.
1180     2. By using declared but undefined structures, we can avoid using "void"
1181     definitions in pcre.h while keeping the internal definitions of the structures
1182     private.
1184     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1185     user point of view, this means that both static and shared libraries are built
1186     by default, but this can be individually controlled. More of the work of
1187     handling this static/shared cases is now inside libtool instead of PCRE's make
1188     file.
1190     4. The pcretest utility is now installed along with pcregrep because it is
1191     useful for users (to test regexs) and by doing this, it automatically gets
1192     relinked by libtool. The documentation has been turned into a man page, so
1193     there are now .1, .txt, and .html versions in /doc.
1195     5. Upgrades to pcregrep:
1196     (i) Added long-form option names like gnu grep.
1197     (ii) Added --help to list all options with an explanatory phrase.
1198     (iii) Added -r, --recursive to recurse into sub-directories.
1199     (iv) Added -f, --file to read patterns from a file.
1201     6. pcre_exec() was referring to its "code" argument before testing that
1202     argument for NULL (and giving an error if it was NULL).
1204     7. Upgraded Makefile.in to allow for compiling in a different directory from
1205     the source directory.
1207     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1208     options bits, the pointer it was passed was to an int instead of to an unsigned
1209     long int. This mattered only on 64-bit systems.
1211     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1212     generated) instead of pcre.in, which it its source. Also made the same change
1213     in several of the .c files.
1215     10. A new release of gcc defines printf() as a macro, which broke pcretest
1216     because it had an ifdef in the middle of a string argument for printf(). Fixed
1217     by using separate calls to printf().
1219     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1220     script, to force use of CR or LF instead of \n in the source. On non-Unix
1221     systems, the value can be set in config.h.
1223     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1224     absolute limit. Changed the text of the error message to make this clear, and
1225     likewise updated the man page.
1227     13. The limit of 99 on the number of capturing subpatterns has been removed.
1228     The new limit is 65535, which I hope will not be a "real" limit.
1231 nigel 51 Version 3.4 22-Aug-00
1232     ---------------------
1234     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1236     2. Diagnose condition (?(0) as an error instead of crashing on matching.
1239 nigel 49 Version 3.3 01-Aug-00
1240     ---------------------
1242     1. If an octal character was given, but the value was greater than \377, it
1243     was not getting masked to the least significant bits, as documented. This could
1244     lead to crashes in some systems.
1246     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
1247     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
1249     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
1250     These just pass their arguments on to (pcre_free)(), but they are provided
1251     because some uses of PCRE bind it to non-C systems that can call its functions,
1252     but cannot call free() or pcre_free() directly.
1254     4. Add "make test" as a synonym for "make check". Corrected some comments in
1255     the Makefile.
1257     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
1258     Makefile.
1260     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
1261     command called pgrep for grepping around the active processes.
1263     7. Added the beginnings of support for UTF-8 character strings.
1265     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
1266     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
1267     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
1268     out for the ar command.)
1271 nigel 47 Version 3.2 12-May-00
1272     ---------------------
1274     This is purely a bug fixing release.
1276     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
1277     of ZA. This was just one example of several cases that could provoke this bug,
1278     which was introduced by change 9 of version 2.00. The code for breaking
1279     infinite loops after an iteration that matches an empty string was't working
1280     correctly.
1282     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
1283     when matched against abbab (for example). After matching an empty string, it
1284     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
1285     caused it to match further down the string than it should.
1287     3. The code contained an inclusion of sys/types.h. It isn't clear why this
1288     was there because it doesn't seem to be needed, and it causes trouble on some
1289     systems, as it is not a Standard C header. It has been removed.
1291     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
1292     were reported on the Macintosh. The changes were from
1294     while ((c = *(++ptr)) != 0 && c != '\n');
1295     to
1296     while ((c = *(++ptr)) != 0 && c != '\n') ;
1298     Totally extraordinary, but if that's what it takes...
1300     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
1301     available. Added HAVE_BCOPY and an autoconf test for it; if neither
1302     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
1303     assumes the way PCRE uses memmove() (always moving upwards).
1305     6. PCRE is being used in one environment where strchr() is not available. There
1306     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
1307     faster code anyway.
1310 nigel 45 Version 3.1 09-Feb-00
1311     ---------------------
1313     The only change in this release is the fixing of some bugs in Makefile.in for
1314     the "install" target:
1316     (1) It was failing to install pcreposix.h.
1318     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
1321 nigel 43 Version 3.0 01-Feb-00
1322     ---------------------
1323 nigel 41
1324     1. Add support for the /+ modifier to perltest (to output $` like it does in
1325     pcretest).
1327     2. Add support for the /g modifier to perltest.
1329     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
1330     matches null strings.
1332     4. Fix perltest so that it doesn't do unwanted things when fed an empty
1333     pattern. Perl treats empty patterns specially - it reuses the most recent
1334     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
1335     effect.
1337     5. The POSIX interface was broken in that it was just handing over the POSIX
1338     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
1339     required a bigger vector, with some working space on the end. This means that
1340     the POSIX wrapper now has to get and free some memory, and copy the results.
1342 nigel 43 6. Added some simple autoconf support, placing the test data and the
1343     documentation in separate directories, re-organizing some of the
1344     information files, and making it build pcre-config (a GNU standard). Also added
1345     libtool support for building PCRE as a shared library, which is now the
1346     default.
1347 nigel 41
1348 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
1349     09 are not valid octal constants. Single digits will be used for minor values
1350     less than 10.
1352     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
1353     existing programs that set these in the POSIX interface can use PCRE without
1354     modification.
1356     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
1357     return all that pcre_info() returns, plus additional data. The pcre_info()
1358     function is retained for compatibility, but is considered to be obsolete.
1360     10. Added experimental recursion feature (?R) to handle one common case that
1361     Perl 5.6 will be able to do with (?p{...}).
1363     11. Added support for POSIX character classes like [:alpha:], which Perl is
1364     adopting.
1367 nigel 39 Version 2.08 31-Aug-99
1368     ----------------------
1370     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
1371     trying to match at the startoffset position, but instead was moving forward to
1372     the next newline as if a previous match had failed.
1374     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
1375     and could get into a loop if a null string was matched other than at the start
1376     of the subject.
1378     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
1379     be distinguished at compile time, and for completeness also added PCRE_DATE.
1381     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
1382     in GnuWin32 environments.
1385 nigel 37 Version 2.07 29-Jul-99
1386     ----------------------
1388     1. The documentation is now supplied in plain text form and HTML as well as in
1389     the form of man page sources.
1391     2. C++ compilers don't like assigning (void *) values to other pointer types.
1392     In particular this affects malloc(). Although there is no problem in Standard
1393     C, I've put in casts to keep C++ compilers happy.
1395     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
1396     should be (const char *).
1398     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
1399     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
1400     However, I haven't made this a standard facility. The documentation doesn't
1401     mention it, and the Makefile doesn't support it.
1403     5. The Makefile now contains an "install" target, with editable destinations at
1404     the top of the file. The pcretest program is not installed.
1406     6. pgrep -V now gives the PCRE version number and date.
1408     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
1409     causing the entire string to be ignored, instead of just the last character.
1411     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
1412     non-matching string, it can take a very, very long time, even for strings of
1413     quite modest length, because of the nested recursion. PCRE now does better in
1414     some of these cases. It does this by remembering the last required literal
1415     character in the pattern, and pre-searching the subject to ensure it is present
1416     before running the real match. In other words, it applies a heuristic to detect
1417     some types of certain failure quickly, and in the above example, if presented
1418     with a string that has no trailing " it gives "no match" very quickly.
1420     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
1421     other alternatives are tried instead.
1424 nigel 35 Version 2.06 09-Jun-99
1425     ----------------------
1427     1. Change pcretest's output for amount of store used to show just the code
1428     space, because the remainder (the data block) varies in size between 32-bit and
1429     64-bit systems.
1431     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
1432     start matching at. This allows lookbehinds to work when searching for multiple
1433     occurrences in a string.
1435     3. Added additional options to pcretest for testing multiple occurrences:
1437     /+ outputs the rest of the string that follows a match
1438     /g loops for multiple occurrences, using the new startoffset argument
1439     /G loops for multiple occurrences by passing an incremented pointer
1441     4. PCRE wasn't doing the "first character" optimization for patterns starting
1442     with \b or \B, though it was doing it for other lookbehind assertions. That is,
1443     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
1444     the letter 'x'. On long subject strings, this gives a significant speed-up.
1447 nigel 33 Version 2.05 21-Apr-99
1448     ----------------------
1450     1. Changed the type of magic_number from int to long int so that it works
1451     properly on 16-bit systems.
1453     2. Fixed a bug which caused patterns starting with .* not to work correctly
1454     when the subject string contained newline characters. PCRE was assuming
1455     anchoring for such patterns in all cases, which is not correct because .* will
1456     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
1457     DOTALL is set at top level; otherwise it knows that patterns starting with .*
1458     must be retried after every newline in the subject.
1461 nigel 31 Version 2.04 18-Feb-99
1462     ----------------------
1464     1. For parenthesized subpatterns with repeats whose minimum was zero, the
1465     computation of the store needed to hold the pattern was incorrect (too large).
1466     If such patterns were nested a few deep, this could multiply and become a real
1467     problem.
1469     2. Added /M option to pcretest to show the memory requirement of a specific
1470     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
1472     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
1473     compiled in such a way that the backtracking after subsequent failure was
1474     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
1475     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
1478 nigel 29 Version 2.03 02-Feb-99
1479     ----------------------
1481     1. Fixed typo and small mistake in man page.
1483 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
1484     LICENCE file containing the conditions.
1485 nigel 29
1486     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
1487     Perl, that is the internal \ allows the delimiter to be included in the
1488     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
1489     the final delimiter, add \ to the end of the pattern (to test the error).
1491     4. Added the convenience functions for extracting substrings after a successful
1492     match. Updated pcretest to make it able to test these functions.
1495 nigel 27 Version 2.02 14-Jan-99
1496     ----------------------
1498     1. Initialized the working variables associated with each extraction so that
1499     their saving and restoring doesn't refer to uninitialized store.
1501     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
1502     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
1503     fix the problem.
1505     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
1506     calls, and wasn't printing the correct value for compiling calls. Increased the
1507     default value of LOOPREPEAT, and the number of significant figures in the
1508     times.
1510     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
1512     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
1513     a building problem on Windows NT with a FAT file system.
1516 nigel 25 Version 2.01 21-Oct-98
1517     ----------------------
1519     1. Changed the API for pcre_compile() to allow for the provision of a pointer
1520     to character tables built by pcre_maketables() in the current locale. If NULL
1521     is passed, the default tables are used.
1524 nigel 23 Version 2.00 24-Sep-98
1525 nigel 21 ----------------------
1527 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
1528     it any more.
1530     2. Allow quantification of (?>) groups, and make it work correctly.
1532     3. The first character computation wasn't working for (?>) groups.
1534     4. Correct the implementation of \Z (it is permitted to match on the \n at the
1535     end of the subject) and add 5.005's \z, which really does match only at the
1536     very end of the subject.
1538     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
1540     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
1541     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
1542     localized options. All options to pcre_study() were also removed.
1544     7. Add other new features from 5.005:
1546     $(?<= positive lookbehind
1547     $(?<! negative lookbehind
1548     (?imsx-imsx) added the unsetting capability
1549     such a setting is global if at outer level; local otherwise
1550     (?imsx-imsx:) non-capturing groups with option setting
1551     (?(cond)re|re) conditional pattern matching
1553     A backreference to itself in a repeated group matches the previous
1554     captured string.
1556     8. General tidying up of studying (both automatic and via "study")
1557     consequential on the addition of new assertions.
1559     9. As in 5.005, unlimited repeated groups that could match an empty substring
1560     are no longer faulted at compile time. Instead, the loop is forcibly broken at
1561     runtime if any iteration does actually match an empty substring.
1563     10. Include the RunTest script in the distribution.
1565     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
1566     discrepancies, some of which were old and were also with respect to 5.004. They
1567     have now been fixed.
1570     Version 1.09 28-Apr-98
1571     ----------------------
1573 nigel 21 1. A negated single character class followed by a quantifier with a minimum
1574     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
1575     program crashes, or just wrong answers. This did not apply to negated classes
1576     containing more than one character, or to minima other than one.
1579 nigel 19 Version 1.08 27-Mar-98
1580     ----------------------
1582     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
1584     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
1585     latter must appear before anything that relies on it in the pattern.
1588 nigel 17 Version 1.07 16-Feb-98
1589     ----------------------
1591     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
1592     repeat of a potentially empty string).
1595 nigel 15 Version 1.06 23-Jan-98
1596     ----------------------
1598     1. Added Markus Oberhumer's little patches for C++.
1600     2. Literal strings longer than 255 characters were broken.
1603 nigel 13 Version 1.05 23-Dec-97
1604     ----------------------
1606     1. Negated character classes containing more than one character were failing if
1607     PCRE_CASELESS was set at run time.
1610 nigel 11 Version 1.04 19-Dec-97
1611     ----------------------
1613     1. Corrected the man page, where some "const" qualifiers had been omitted.
1615     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
1616     input syntax.
1618     3. Fixed memory leak which occurred when a regex with back references was
1619     matched with an offsets vector that wasn't big enough. The temporary memory
1620     that is used in this case wasn't being freed if the match failed.
1622     4. Tidied pcretest to ensure it frees memory that it gets.
1624     5. Temporary memory was being obtained in the case where the passed offsets
1625     vector was exactly big enough.
1627     6. Corrected definition of offsetof() from change 5 below.
1629     7. I had screwed up change 6 below and broken the rules for the use of
1630     setjmp(). Now fixed.
1633 nigel 9 Version 1.03 18-Dec-97
1634     ----------------------
1636     1. A erroneous regex with a missing opening parenthesis was correctly
1637     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
1638     on some systems.
1640     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
1641     it was reported that one broken compiler failed on the former because "code" is
1642     also an independent variable.
1644     3. The erroneous regex a[]b caused an array overrun reference.
1646     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
1647     fail on data ending with that character. (It was going on too far, and checking
1648     the next character, typically a binary zero.) This was specific to the
1649     optimized code for single-character negative classes.
1651     5. Added a contributed patch from the TIN world which does the following:
1653     + Add an undef for memmove, in case the the system defines a macro for it.
1655     + Add a definition of offsetof(), in case there isn't one. (I don't know
1656     the reason behind this - offsetof() is part of the ANSI standard - but
1657     it does no harm).
1659     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
1660     most of the places where whitespace preceded '#'. I have given up and
1661     allowed the remaining 2 cases to be at the margin.
1663     + Rename some variables in pcre to eliminate shadowing. This seems very
1664     pedantic, but does no harm, of course.
1666     6. Moved the call to setjmp() into its own function, to get rid of warnings
1667     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
1669     7. Constructs such as \d{8,} were compiling into the equivalent of
1670 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
1671 nigel 9 outcome, but in this particular case used more store than had been allocated,
1672     which caused the bug to be discovered because it threw up an internal error.
1674     8. The debugging code in both pcre and pcretest for outputting the compiled
1675     form of a regex was going wrong in the case of back references followed by
1676     curly-bracketed repeats.
1679 nigel 7 Version 1.02 12-Dec-97
1680     ----------------------
1682     1. Typos in pcre.3 and comments in the source fixed.
1684     2. Applied a contributed patch to get rid of places where it used to remove
1685     'const' from variables, and fixed some signed/unsigned and uninitialized
1686     variable warnings.
1688     3. Added the "runtest" target to Makefile.
1690     4. Set default compiler flag to -O2 rather than just -O.
1693 nigel 5 Version 1.01 19-Nov-97
1694     ----------------------
1696     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
1697     like /([ab]*)*/, that is, for classes with more than one character in them.
1699     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
1700     as /((?>a*))*/ (a PCRE_EXTRA facility).
1703     Version 1.00 18-Nov-97
1704     ----------------------
1706     1. Added compile-time macros to support systems such as SunOS4 which don't have
1707     memmove() or strerror() but have other things that can be used instead.
1709     2. Arranged that "make clean" removes the executables.
1712 nigel 3 Version 0.99 27-Oct-97
1713     ----------------------
1715     1. Fixed bug in code for optimizing classes with only one character. It was
1716     initializing a 32-byte map regardless, which could cause it to run off the end
1717     of the memory it had got.
1719     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
1722     Version 0.98 22-Oct-97
1723     ----------------------
1725     1. Fixed bug in code for handling temporary memory usage when there are more
1726     back references than supplied space in the ovector. This could cause segfaults.
1729     Version 0.97 21-Oct-97
1730     ----------------------
1732     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
1734     2. Optimized negated single characters not to use a bit map.
1736     3. Brought error texts together as macro definitions; clarified some of them;
1737     fixed one that was wrong - it said "range out of order" when it meant "invalid
1738     escape sequence".
1740     4. Changed some char * arguments to const char *.
1742     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
1744     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
1745     pcretest.
1748     Version 0.96 16-Oct-97
1749     ----------------------
1751     1. Added a simple "pgrep" utility to the distribution.
1753     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
1754     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
1755     where "ddd" means "one or more decimal digits".
1757     3. Fixed serious bug. If a pattern had a back reference, but the call to
1758     pcre_exec() didn't supply a large enough ovector to record the related
1759     identifying subpattern, the match always failed. PCRE now remembers the number
1760     of the largest back reference, and gets some temporary memory in which to save
1761     the offsets during matching if necessary, in order to ensure that
1762     backreferences always work.
1764     4. Increased the compatibility with Perl in a number of ways:
1766     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
1767     to request this handling. The option can be set at compile or exec time.
1769     (b) $ matches before a terminating newline by default; an option
1770     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
1771     mode). The option can be set at compile or exec time.
1773     (c) The handling of \ followed by a digit other than 0 is now supposed to be
1774     the same as Perl's. If the decimal number it represents is less than 10
1775     or there aren't that many previous left capturing parentheses, an octal
1776     escape is read. Inside a character class, it's always an octal escape,
1777     even if it is a single digit.
1779     (d) An escaped but undefined alphabetic character is taken as a literal,
1780     unless PCRE_EXTRA is set. Currently this just reserves the remaining
1781     escapes.
1783     (e) {0} is now permitted. (The previous item is removed from the compiled
1784     pattern).
1786     5. Changed all the names of code files so that the basic parts are no longer
1787     than 10 characters, and abolished the teeny "globals.c" file.
1789     6. Changed the handling of character classes; they are now done with a 32-byte
1790     bit map always.
1792     7. Added the -d and /D options to pcretest to make it possible to look at the
1793     internals of compilation without having to recompile pcre.
1796     Version 0.95 23-Sep-97
1797     ----------------------
1799     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
1800     \x20 at the start of a run of normal characters. These were being treated as
1801     real characters, instead of the source characters being re-checked.
1804     Version 0.94 18-Sep-97
1805     ----------------------
1807     1. The functions are now thread-safe, with the caveat that the global variables
1808     containing pointers to malloc() and free() or alternative functions are the
1809     same for all threads.
1811     2. Get pcre_study() to generate a bitmap of initial characters for non-
1812     anchored patterns when this is possible, and use it if passed to pcre_exec().
1815     Version 0.93 15-Sep-97
1816     ----------------------
1818     1. /(b)|(:+)/ was computing an incorrect first character.
1820     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
1821     but not actually doing anything yet.
1823     3. Treat "-" characters in classes that cannot be part of ranges as literals,
1824     as Perl does (e.g. [-az] or [az-]).
1826     4. Set the anchored flag if a branch starts with .* or .*? because that tests
1827     all possible positions.
1829     5. Split up into different modules to avoid including unneeded functions in a
1830     compiled binary. However, compile and exec are still in one module. The "study"
1831     function is split off.
1833     6. The character tables are now in a separate module whose source is generated
1834     by an auxiliary program - but can then be edited by hand if required. There are
1835     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
1836     toupper() in the code.
1838     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
1839     make them global. Abolish the function for setting them, as the caller can now
1840     set them directly.
1843     Version 0.92 11-Sep-97
1844     ----------------------
1846     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
1847     (e.g. /a{1,3}/) was broken (I mis-optimized it).
1849     2. Caseless matching was not working in character classes if the characters in
1850     the pattern were in upper case.
1852     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
1854     4. Make PCRE_ANCHORED public and accept as a compile option.
1856     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
1857     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
1858     pass them.
1860     6. Give an error if bad option bits passed at compile or run time.
1862     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
1863     pcretest to cause it to pass that flag.
1865     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
1866     options, and the first character, if set.
1868     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
1871     Version 0.91 10-Sep-97
1872     ----------------------
1874     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
1875     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
1877     2. PCRE was looping on encountering an indefinitely repeated back reference to
1878     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
1879     Perl does - treats the match as successful.
1881     ****

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