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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 77 Version 6.0 07-Jun-05
5     ---------------------
6    
7     1. Some minor internal re-organization to help with my DFA experiments.
8    
9     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
10     didn't matter for the library itself when fully configured, but did matter
11     when compiling without UCP support, or within Exim, where the ucp files are
12     not imported.
13    
14     3. Refactoring of the library code to split up the various functions into
15     different source modules. The addition of the new DFA matching code (see
16     below) to a single monolithic source would have made it really too
17     unwieldy, quite apart from causing all the code to be include in a
18     statically linked application, when only some functions are used. This is
19     relevant even without the DFA addition now that patterns can be compiled in
20     one application and matched in another.
21    
22     The downside of splitting up is that there have to be some external
23     functions and data tables that are used internally in different modules of
24     the library but which are not part of the API. These have all had their
25     names changed to start with "_pcre_" so that they are unlikely to clash
26     with other external names.
27    
28     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
29     a different (DFA) algorithm. Although it is slower than the original
30     function, it does have some advantages for certain types of matching
31     problem.
32    
33     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
34     including restarting after a partial match.
35    
36     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
37     defined when compiling for Windows was sent to me. I have put it into the
38     code, though I have no means of testing or verifying it.
39    
40     7. Added the pcre_refcount() auxiliary function.
41    
42     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
43     match before or at the first newline in the subject string. In pcretest,
44     the /f option on a pattern can be used to set this.
45    
46     9. A repeated \w when used in UTF-8 mode with characters greater than 256
47     would behave wrongly. This has been present in PCRE since release 4.0.
48    
49     10. A number of changes to the pcregrep command:
50    
51     (a) Refactored how -x works; insert ^(...)$ instead of setting
52     PCRE_ANCHORED and checking the length, in preparation for adding
53     something similar for -w.
54    
55     (b) Added the -w (match as a word) option.
56    
57     (c) Refactored the way lines are read and buffered so as to have more
58     than one at a time available.
59    
60     (d) Implemented a pcregrep test script.
61    
62     (e) Added the -M (multiline match) option. This allows patterns to match
63     over several lines of the subject. The buffering ensures that at least
64     8K, or the rest of the document (whichever is the shorter) is available
65     for matching (and similarly the previous 8K for lookbehind assertions).
66    
67     (f) Changed the --help output so that it now says
68    
69     -w, --word-regex(p)
70    
71     instead of two lines, one with "regex" and the other with "regexp"
72     because that confused at least one person since the short forms are the
73     same. (This required a bit of code, as the output is generated
74     automatically from a table. It wasn't just a text change.)
75    
76     (g) -- can be used to terminate pcregrep options if the next thing isn't an
77     option but starts with a hyphen. Could be a pattern or a path name
78     starting with a hyphen, for instance.
79    
80     (h) "-" can be given as a file name to represent stdin.
81    
82     (i) When file names are being printed, "(standard input)" is used for
83     the standard input, for compatibility with GNU grep. Previously
84     "<stdin>" was used.
85    
86     (j) The option --label=xxx can be used to supply a name to be used for
87     stdin when file names are being printed. There is no short form.
88    
89     (k) Re-factored the options decoding logic because we are going to add
90     two more options that take data. Such options can now be given in four
91     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
92    
93     (l) Added the -A, -B, and -C options for requesting that lines of context
94     around matches be printed.
95    
96     (m) Added the -L option to print the names of files that do not contain
97     any matching lines, that is, the complement of -l.
98    
99     (n) The return code is 2 if any file cannot be opened, but pcregrep does
100     continue to scan other files.
101    
102     (o) The -s option was incorrectly implemented. For compatibility with other
103     greps, it now suppresses the error message for a non-existent or non-
104     accessible file (but not the return code). There is a new option called
105     -q that suppresses the output of matching lines, which was what -s was
106     previously doing.
107    
108     (p) Added --include and --exclude options to specify files for inclusion
109     and exclusion when recursing.
110    
111     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
112     Hopefully, it now does.
113    
114     12. Missing cast in pcre_study().
115    
116     13. Added an "uninstall" target to the makefile.
117    
118     14. Replaced "extern" in the function prototypes in Makefile.in with
119     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
120     world, but is set differently for Windows.
121    
122     15. Added a second compiling function called pcre_compile2(). The only
123     difference is that it has an extra argument, which is a pointer to an
124     integer error code. When there is a compile-time failure, this is set
125     non-zero, in addition to the error test pointer being set to point to an
126     error message. The new argument may be NULL if no error number is required
127     (but then you may as well call pcre_compile(), which is now just a
128     wrapper). This facility is provided because some applications need a
129     numeric error indication, but it has also enabled me to tidy up the way
130     compile-time errors are handled in the POSIX wrapper.
131    
132     16. Added VPATH=.libs to the makefile; this should help when building with one
133     prefix path and installing with another. (Or so I'm told by someone who
134     knows more about this stuff than I do.)
135    
136     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
137     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
138     match everything, including newlines. This is not POSIX-compatible, but
139     somebody wanted the feature. From pcretest it can be activated by using
140     both the P and the s flags.
141    
142     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
143    
144     19. libpcre.pc was being incorrectly installed as executable.
145    
146     20. A couple of places in pcretest check for end-of-line by looking for '\n';
147     it now also looks for '\r' so that it will work unmodified on Windows.
148    
149     21. Added Google's contributed C++ wrapper to the distribution.
150    
151     22. Added some untidy missing memory free() calls in pcretest, to keep
152     Electric Fence happy when testing.
153    
154    
155    
156 nigel 75 Version 5.0 13-Sep-04
157     ---------------------
158    
159     1. Internal change: literal characters are no longer packed up into items
160     containing multiple characters in a single byte-string. Each character
161     is now matched using a separate opcode. However, there may be more than one
162     byte in the character in UTF-8 mode.
163    
164     2. The pcre_callout_block structure has two new fields: pattern_position and
165     next_item_length. These contain the offset in the pattern to the next match
166     item, and its length, respectively.
167    
168     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
169     insertion of callouts before each pattern item. Added the /C option to
170     pcretest to make use of this.
171    
172     4. On the advice of a Windows user, the lines
173    
174     #if defined(_WIN32) || defined(WIN32)
175     _setmode( _fileno( stdout ), 0x8000 );
176     #endif /* defined(_WIN32) || defined(WIN32) */
177    
178     have been added to the source of pcretest. This apparently does useful
179     magic in relation to line terminators.
180    
181     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
182     for the benefit of those environments where the "b" makes a difference.
183    
184     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
185     to know about it. I have put a hack into configure.in that adds in code
186     to set GCC=yes if CC=icc. This seems to end up at a point in the
187     generated configure script that is early enough to affect the setting of
188     compiler options, which is what is needed, but I have no means of testing
189     whether it really works. (The user who reported this had patched the
190     generated configure script, which of course I cannot do.)
191    
192     LATER: After change 22 below (new libtool files), the configure script
193     seems to know about icc (and also ecc). Therefore, I have commented out
194     this hack in configure.in.
195    
196     7. Added support for pkg-config (2 patches were sent in).
197    
198     8. Negated POSIX character classes that used a combination of internal tables
199     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
200     [[:^ascii]]. Typically, they would match almost any characters. The other
201     POSIX classes were not broken in this way.
202    
203     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
204     to find the match, as PCRE was deluded into thinking that the match had to
205     start at the start point or following a newline. The same bug applied to
206     patterns with negative forward assertions or any backward assertions
207     preceding ".*" at the start, unless the pattern required a fixed first
208     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
209    
210     10. In UTF-8 mode, when moving forwards in the subject after a failed match
211     starting at the last subject character, bytes beyond the end of the subject
212     string were read.
213    
214     11. Renamed the variable "class" as "classbits" to make life easier for C++
215     users. (Previously there was a macro definition, but it apparently wasn't
216     enough.)
217    
218     12. Added the new field "tables" to the extra data so that tables can be passed
219     in at exec time, or the internal tables can be re-selected. This allows
220     a compiled regex to be saved and re-used at a later time by a different
221     program that might have everything at different addresses.
222    
223     13. Modified the pcre-config script so that, when run on Solaris, it shows a
224     -R library as well as a -L library.
225    
226     14. The debugging options of pcretest (-d on the command line or D on a
227     pattern) showed incorrect output for anything following an extended class
228     that contained multibyte characters and which was followed by a quantifier.
229    
230     15. Added optional support for general category Unicode character properties
231     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
232     support. It adds about 90K to the size of the library. The meanings of the
233     inbuilt class escapes such as \d and \s have NOT been changed.
234    
235     16. Updated pcredemo.c to include calls to free() to release the memory for the
236     compiled pattern.
237    
238     17. The generated file chartables.c was being created in the source directory
239     instead of in the building directory. This caused the build to fail if the
240     source directory was different from the building directory, and was
241     read-only.
242    
243     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
244     file. No doubt somebody will tell me if they don't make sense... Also added
245     Dan Mooney's comments about building on OpenVMS.
246    
247     19. Added support for partial matching via the PCRE_PARTIAL option for
248     pcre_exec() and the \P data escape in pcretest.
249    
250     20. Extended pcretest with 3 new pattern features:
251    
252     (i) A pattern option of the form ">rest-of-line" causes pcretest to
253     write the compiled pattern to the file whose name is "rest-of-line".
254     This is a straight binary dump of the data, with the saved pointer to
255     the character tables forced to be NULL. The study data, if any, is
256     written too. After writing, pcretest reads a new pattern.
257    
258     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
259     compiled pattern from the given file. There must not be any
260     occurrences of "<" in the file name (pretty unlikely); if there are,
261     pcretest will instead treat the initial "<" as a pattern delimiter.
262     After reading in the pattern, pcretest goes on to read data lines as
263     usual.
264    
265     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
266     and 16-bit fields in a compiled pattern, to simulate a pattern that
267     was compiled on a host of opposite endianness.
268    
269     21. The pcre-exec() function can now cope with patterns that were compiled on
270     hosts of opposite endianness, with this restriction:
271    
272     As for any compiled expression that is saved and used later, the tables
273     pointer field cannot be preserved; the extra_data field in the arguments
274     to pcre_exec() should be used to pass in a tables address if a value
275     other than the default internal tables were used at compile time.
276    
277     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
278     now diagnosed as an error. Previously, most of the time, a negative number
279     would have been treated as zero, but if in addition "ovector" was passed as
280     NULL, a crash could occur.
281    
282     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
283     new versions from the libtool 1.5 distribution (the last one is a copy of
284     a file called libtool.m4). This seems to have fixed the need to patch
285     "configure" to support Darwin 1.3 (which I used to do). However, I still
286     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
287     workstation).
288    
289     24. Changed the PCRE licence to be the more standard "BSD" licence.
290    
291    
292 nigel 73 Version 4.5 01-Dec-03
293     ---------------------
294    
295     1. There has been some re-arrangement of the code for the match() function so
296     that it can be compiled in a version that does not call itself recursively.
297     Instead, it keeps those local variables that need separate instances for
298     each "recursion" in a frame on the heap, and gets/frees frames whenever it
299     needs to "recurse". Keeping track of where control must go is done by means
300     of setjmp/longjmp. The whole thing is implemented by a set of macros that
301     hide most of the details from the main code, and operates only if
302     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
303     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
304     operating.
305    
306     To make it easier for callers to provide specially tailored get/free
307     functions for this usage, two new functions, pcre_stack_malloc, and
308     pcre_stack_free, are used. They are always called in strict stacking order,
309     and the size of block requested is always the same.
310    
311     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
312     PCRE has been compiled to use the stack or the heap for recursion. The
313     -C option of pcretest uses this to show which version is compiled.
314    
315     A new data escape \S, is added to pcretest; it causes the amounts of store
316     obtained and freed by both kinds of malloc/free at match time to be added
317     to the output.
318    
319     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
320     what's available on my current Linux desktop machine.
321    
322     3. When matching a UTF-8 string, the test for a valid string at the start has
323     been extended. If start_offset is not zero, PCRE now checks that it points
324     to a byte that is the start of a UTF-8 character. If not, it returns
325     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
326     this is necessary because there may be backward assertions in the pattern.
327     When matching the same subject several times, it may save resources to use
328     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
329    
330     4. The code for checking the validity of UTF-8 strings has been tightened so
331     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
332     containing "overlong sequences".
333    
334     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
335     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
336     should have been "&", but it just so happened that all the cases this let
337     through by mistake were picked up later in the function.
338    
339     6. I had used a variable called "isblank" - this is a C99 function, causing
340     some compilers to warn. To avoid this, I renamed it (as "blankclass").
341    
342     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
343     prompting; (b) run "./pcretest /dev/null" at the start of the test script
344     so the version is shown; (c) stop "make test" echoing "./RunTest".
345    
346     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
347    
348     9. The prototype for memmove() for systems that don't have it was using
349     size_t, but the inclusion of the header that defines size_t was later. I've
350     moved the #includes for the C headers earlier to avoid this.
351    
352     10. Added some adjustments to the code to make it easier to compiler on certain
353     special systems:
354    
355     (a) Some "const" qualifiers were missing.
356     (b) Added the macro EXPORT before all exported functions; by default this
357     is defined to be empty.
358     (c) Changed the dftables auxiliary program (that builds chartables.c) so
359     that it reads its output file name as an argument instead of writing
360     to the standard output and assuming this can be redirected.
361    
362     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
363     class containing characters with values greater than 255, PCRE compilation
364     went into a loop.
365    
366     12. A recursive reference to a subpattern that was within another subpattern
367     that had a minimum quantifier of zero caused PCRE to crash. For example,
368     (x(y(?2))z)? provoked this bug with a subject that got as far as the
369     recursion. If the recursively-called subpattern itself had a zero repeat,
370     that was OK.
371    
372     13. In pcretest, the buffer for reading a data line was set at 30K, but the
373     buffer into which it was copied (for escape processing) was still set at
374     1024, so long lines caused crashes.
375    
376     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
377     "internal error: code overflow...". This applied to any character class
378     that was followed by a possessive quantifier.
379    
380     15. Modified the Makefile to add libpcre.la as a prerequisite for
381     libpcreposix.la because I was told this is needed for a parallel build to
382     work.
383    
384     16. If a pattern that contained .* following optional items at the start was
385     studied, the wrong optimizing data was generated, leading to matching
386     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
387     matching string must start with a or b or c. The correct conclusion for
388     this pattern is that a match can start with any character.
389    
390    
391 nigel 71 Version 4.4 13-Aug-03
392     ---------------------
393    
394     1. In UTF-8 mode, a character class containing characters with values between
395     127 and 255 was not handled correctly if the compiled pattern was studied.
396     In fixing this, I have also improved the studying algorithm for such
397     classes (slightly).
398    
399     2. Three internal functions had redundant arguments passed to them. Removal
400     might give a very teeny performance improvement.
401    
402     3. Documentation bug: the value of the capture_top field in a callout is *one
403     more than* the number of the hightest numbered captured substring.
404    
405     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
406     in incorrectly linking with a previously installed version. They now link
407     explicitly with libpcre.la.
408    
409     5. configure.in no longer needs to recognize Cygwin specially.
410    
411     6. A problem in pcre.in for Windows platforms is fixed.
412    
413     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
414     pcretest, it used to include the size of the study block as part of its
415     output. Unfortunately, the structure contains a field that has a different
416     size on different hardware architectures. This meant that the tests that
417     showed this size failed. As the block is currently always of a fixed size,
418     this information isn't actually particularly useful in pcretest output, so
419     I have just removed it.
420    
421     8. Three pre-processor statements accidentally did not start in column 1.
422     Sadly, there are *still* compilers around that complain, even though
423     standard C has not required this for well over a decade. Sigh.
424    
425     9. In pcretest, the code for checking callouts passed small integers in the
426     callout_data field, which is a void * field. However, some picky compilers
427     complained about the casts involved for this on 64-bit systems. Now
428     pcretest passes the address of the small integer instead, which should get
429     rid of the warnings.
430    
431     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
432     both compile and run time, and gives an error if an invalid UTF-8 sequence
433     is found. There is a option for disabling this check in cases where the
434     string is known to be correct and/or the maximum performance is wanted.
435    
436     11. In response to a bug report, I changed one line in Makefile.in from
437    
438     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
439     to
440     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
441    
442     to look similar to other lines, but I have no way of telling whether this
443     is the right thing to do, as I do not use Windows. No doubt I'll get told
444     if it's wrong...
445    
446    
447 nigel 69 Version 4.3 21-May-03
448     ---------------------
449    
450     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
451     Makefile.
452    
453     2. Some refactoring to improve the quality of the code:
454    
455     (i) The utf8_table... variables are now declared "const".
456    
457     (ii) The code for \cx, which used the "case flipping" table to upper case
458     lower case letters, now just substracts 32. This is ASCII-specific,
459     but the whole concept of \cx is ASCII-specific, so it seems
460     reasonable.
461    
462     (iii) PCRE was using its character types table to recognize decimal and
463     hexadecimal digits in the pattern. This is silly, because it handles
464     only 0-9, a-f, and A-F, but the character types table is locale-
465     specific, which means strange things might happen. A private
466     table is now used for this - though it costs 256 bytes, a table is
467     much faster than multiple explicit tests. Of course, the standard
468     character types table is still used for matching digits in subject
469     strings against \d.
470    
471     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
472     ending in _t are). So I've renamed it as ESC_tee.
473    
474     3. The first argument for regexec() in the POSIX wrapper should have been
475     defined as "const".
476    
477     4. Changed pcretest to use malloc() for its buffers so that they can be
478     Electric Fenced for debugging.
479    
480     5. There were several places in the code where, in UTF-8 mode, PCRE would try
481     to read one or more bytes before the start of the subject string. Often this
482     had no effect on PCRE's behaviour, but in some circumstances it could
483     provoke a segmentation fault.
484    
485     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
486     to try to read one or more bytes before the start of the subject string.
487    
488     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
489     UTF-8 support could misbehave in various ways if the subject string
490     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
491     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
492     back over UTF-8 characters.)
493    
494    
495 nigel 67 Version 4.2 14-Apr-03
496     ---------------------
497    
498     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
499    
500     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
501     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
502     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
503     [WIN_PREFIX]: new variable, "cyg" for Cygwin
504     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
505     and BUILD_EXEEXT
506     Note: automatic setting of the BUILD variables is not yet working
507     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
508     compile-time but not at link-time
509     [LINK]: use for linking executables only
510     make different versions for Windows and non-Windows
511     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
512     libraries
513     [LINK_FOR_BUILD]: new variable
514     [OBJEXT]: use throughout
515     [EXEEXT]: use throughout
516     <winshared>: new target
517     <wininstall>: new target
518     <dftables.o>: use native compiler
519     <dftables>: use native linker
520     <install>: handle Windows platform correctly
521     <clean>: ditto
522     <check>: ditto
523     copy DLL to top builddir before testing
524    
525     As part of these changes, -no-undefined was removed again. This was reported
526     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
527     in any case.
528    
529     3. Some tidies to get rid of compiler warnings:
530    
531     . In the match_data structure, match_limit was an unsigned long int, whereas
532     match_call_count was an int. I've made them both unsigned long ints.
533    
534     . In pcretest the fact that a const uschar * doesn't automatically cast to
535     a void * provoked a warning.
536    
537     . Turning on some more compiler warnings threw up some "shadow" variables
538     and a few more missing casts.
539    
540     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
541     option, a class that contained a single character with a value between 128
542     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
543    
544     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
545     option, a class that contained several characters, but with at least one
546     whose value was between 128 and 255 caused PCRE to crash.
547    
548    
549 nigel 65 Version 4.1 12-Mar-03
550     ---------------------
551 nigel 63
552 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
553     needed, and a string in dftables.c that was longer than standard compilers are
554     required to support.
555    
556     2. Compiling with Sun's compiler found a few more places where the code could
557     be tidied up in order to avoid warnings.
558    
559     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
560     first of these names is deprecated in the latest Autoconf in favour of the name
561     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
562     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
563     analogy I have changed it to CFLAGS_FOR_BUILD.
564    
565     4. Added -no-undefined to the linking command in the Makefile, because this is
566     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
567     linking step for the pcreposix library.
568    
569     5. PCRE was failing to diagnose the case of two named groups with the same
570     name.
571    
572     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
573     literal character that is needed in the subject for a match, and scans along to
574     ensure that it is present before embarking on the full matching process. This
575     saves time in cases of nested unlimited repeats that are never going to match.
576     Problem: the scan can take a lot of time if the subject is very long (e.g.
577     megabytes), thus penalizing straightforward matches. It is now done only if the
578     amount of subject to be scanned is less than 1000 bytes.
579    
580     7. A lesser problem with the same optimization is that it was recording the
581     first character of an anchored pattern as "needed", thus provoking a search
582     right along the subject, even when the first match of the pattern was going to
583     fail. The "needed" character is now not set for anchored patterns, unless it
584     follows something in the pattern that is of non-fixed length. Thus, it still
585     fulfils its original purpose of finding quick non-matches in cases of nested
586     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
587    
588    
589     Version 4.0 17-Feb-03
590     ---------------------
591    
592 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
593     extended to the end of string, PCRE compiled incorrect data. This could lead to
594     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
595    
596     2. Moved to autoconf 2.53 and libtool 1.4.2.
597    
598     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
599     the special perltest8 script is no longer needed - all the tests can be run
600     from a single perltest script.
601    
602     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
603     by \s. It has now been removed in PCRE. This means it isn't recognized as
604     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
605     class [:space:] *does* include VT, thereby creating a mess.
606    
607     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
608     space and tab.
609    
610     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
611     its new features into the main test script, reducing the number of scripts.
612    
613     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
614     were backward compatible, and made the (?i) apply to the whole pattern, as if
615     /i were given. Now it behaves more logically, and applies the option setting
616     only to what follows. PCRE has been changed to follow suit. However, if it
617     finds options settings right at the start of the pattern, it extracts them into
618     the global options, as before. Thus, they show up in the info data.
619    
620     8. Added support for the \Q...\E escape sequence. Characters in between are
621     treated as literals. This is slightly different from Perl in that $ and @ are
622     also handled as literals inside the quotes. In Perl, they will cause variable
623     interpolation. Note the following examples:
624    
625     Pattern PCRE matches Perl matches
626    
627     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
628     \Qabc\$xyz\E abc\$xyz abc\$xyz
629     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
630    
631     For compatibility with Perl, \Q...\E sequences are recognized inside character
632     classes as well as outside them.
633    
634     9. Re-organized 3 code statements in pcretest to avoid "overflow in
635     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
636     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
637     signed/unsigned warnings.
638    
639     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
640     option for pcretest, so I've replaced it by a simple function that does just
641     that job.
642    
643     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
644     "pcregrep -".
645    
646     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
647     Java package. This provides some syntactic sugar for simple cases of what my
648     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
649     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
650     item, you can use this simplified notation. Note that only makes sense with
651     greedy quantifiers. Consequently, the use of the possessive quantifier forces
652     greediness, whatever the setting of the PCRE_UNGREEDY option.
653    
654     13. A change of greediness default within a pattern was not taking effect at
655     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
656     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
657     was abstracted outside.
658    
659     14. PCRE now supports the \G assertion. It is true when the current matching
660     position is at the start point of the match. This differs from \A when the
661     starting offset is non-zero. Used with the /g option of pcretest (or similar
662     code), it works in the same way as it does for Perl's /g option. If all
663     alternatives of a regex begin with \G, the expression is anchored to the start
664     match position, and the "anchored" flag is set in the compiled expression.
665    
666     15. Some bugs concerning the handling of certain option changes within patterns
667     have been fixed. These applied to options other than (?ims). For example,
668     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
669     been the other way round. Some of this was related to change 7 above.
670    
671     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
672     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
673     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
674     POSIX classes only within a class (e.g. /[[:alpha:]]/).
675    
676     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
677     mode. Unlike ".", it always matches newline, whatever the setting of
678     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
679     assertions. Perl allows it, but it doesn't (in general) work because it can't
680     calculate the length of the lookbehind. At least, that's the case for Perl
681     5.8.0 - I've been told they are going to document that it doesn't work in
682     future.
683    
684     18. Added an error diagnosis for escapes that PCRE does not support: these are
685     \L, \l, \N, \P, \p, \U, \u, and \X.
686    
687     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
688     reading past the end of the pattern in cases such as /[abcd/.
689    
690     20. PCRE was getting more memory than necessary for patterns with classes that
691     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
692    
693     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
694     compiling PCRE for use with Virtual Pascal.
695    
696     22. Small fix to the Makefile to make it work properly if the build is done
697     outside the source tree.
698    
699     23. Added a new extension: a condition to go with recursion. If a conditional
700     subpattern starts with (?(R) the "true" branch is used if recursion has
701     happened, whereas the "false" branch is used only at the top level.
702    
703     24. When there was a very long string of literal characters (over 255 bytes
704     without UTF support, over 250 bytes with UTF support), the computation of how
705     much memory was required could be incorrect, leading to segfaults or other
706     strange effects.
707    
708     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
709     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
710     there was a subsequent back reference to those brackets. This meant that, for
711     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
712     possible to check for precisely this case. All we can do is abandon the
713     optimization if .* occurs inside capturing brackets when there are any back
714     references whatsoever. (See below for a better fix that came later.)
715    
716     26. The handling of the optimization for finding the first character of a
717     non-anchored pattern, and for finding a character that is required later in the
718     match were failing in some cases. This didn't break the matching; it just
719     failed to optimize when it could. The way this is done has been re-implemented.
720    
721     27. Fixed typo in error message for invalid (?R item (it said "(?p").
722    
723     28. Added a new feature that provides some of the functionality that Perl
724     provides with (?{...}). The facility is termed a "callout". The way it is done
725     in PCRE is for the caller to provide an optional function, by setting
726     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
727     global variable. By default it is unset, which disables all calling out. To get
728     the function called, the regex must include (?C) at appropriate points. This
729     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
730     This provides a means of identifying different callout points. When PCRE
731     reaches such a point in the regex, if pcre_callout has been set, the external
732     function is called. It is provided with data in a structure called
733     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
734     matching continues; if it returns a non-zero value, the match at the current
735     point fails. However, backtracking will occur if possible. [This was changed
736     later and other features added - see item 49 below.]
737    
738     29. pcretest is upgraded to test the callout functionality. It provides a
739     callout function that displays information. By default, it shows the start of
740     the match and the current position in the text. There are some new data escapes
741     to vary what happens:
742    
743     \C+ in addition, show current contents of captured substrings
744     \C- do not supply a callout function
745     \C!n return 1 when callout number n is reached
746     \C!n!m return 1 when callout number n is reached for the mth time
747    
748     30. If pcregrep was called with the -l option and just a single file name, it
749     output "<stdin>" if a match was found, instead of the file name.
750    
751     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
752     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
753     pcre_exec(). This saves a malloc/free per call. The default value of
754     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
755     when configuring.
756    
757     32. The default maximum size of a compiled pattern is 64K. There have been a
758     few cases of people hitting this limit. The code now uses macros to handle the
759     storing of links as offsets within the compiled pattern. It defaults to 2-byte
760     links, but this can be changed to 3 or 4 bytes by --with-link-size when
761     configuring. Tests 2 and 5 work only with 2-byte links because they output
762     debugging information about compiled patterns.
763    
764     33. Internal code re-arrangements:
765    
766     (a) Moved the debugging function for printing out a compiled regex into
767     its own source file (printint.c) and used #include to pull it into
768     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
769     separate copies.
770    
771     (b) Defined the list of op-code names for debugging as a macro in
772     internal.h so that it is next to the definition of the opcodes.
773    
774     (c) Defined a table of op-code lengths for simpler skipping along compiled
775     code. This is again a macro in internal.h so that it is next to the
776     definition of the opcodes.
777    
778     34. Added support for recursive calls to individual subpatterns, along the
779     lines of Robin Houston's patch (but implemented somewhat differently).
780    
781     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
782     allow it to read and process whole directories in Win32. This code was
783     contributed by Lionel Fourquaux; it has not been tested by me.
784    
785     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
786     used to name a group. Names consist of alphanumerics and underscores, and must
787     be unique. Back references use the syntax (?P=name) and recursive calls use
788     (?P>name) which is a PCRE extension to the Python extension. Groups still have
789     numbers. The function pcre_fullinfo() can be used after compilation to extract
790     a name/number map. There are three relevant calls:
791    
792     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
793     PCRE_INFO_NAMECOUNT yields the number of entries
794     PCRE_INFO_NAMETABLE yields a pointer to the map.
795    
796     The map is a vector of fixed-size entries. The size of each entry depends on
797     the length of the longest name used. The first two bytes of each entry are the
798     group number, most significant byte first. There follows the corresponding
799     name, zero terminated. The names are in alphabetical order.
800    
801     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
802     case instead of 255. Making it the same both with and without UTF-8 support
803     means that the same test output works with both.
804    
805     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
806     calling malloc() with a zero argument.
807    
808     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
809     optimization. I've improved things by keeping a bitmap of backreferences with
810     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
811     fact referenced, the optimization can be applied. It is unlikely that a
812     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
813     the match to follow \n) will appear inside brackets with a number greater than
814     31, but if it does, any back reference > 31 suppresses the optimization.
815    
816     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
817     of disabling numbered capturing parentheses. Any opening parenthesis that is
818     not followed by ? behaves as if it were followed by ?: but named parentheses
819     can still be used for capturing (and they will acquire numbers in the usual
820     way).
821    
822     41. Redesigned the return codes from the match() function into yes/no/error so
823     that errors can be passed back from deep inside the nested calls. A malloc
824     failure while inside a recursive subpattern call now causes the
825     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
826    
827     42. It is now possible to set a limit on the number of times the match()
828     function is called in a call to pcre_exec(). This facility makes it possible to
829     limit the amount of recursion and backtracking, though not in a directly
830     obvious way, because the match() function is used in a number of different
831     circumstances. The count starts from zero for each position in the subject
832     string (for non-anchored patterns). The default limit is, for compatibility, a
833     large number, namely 10 000 000. You can change this in two ways:
834    
835     (a) When configuring PCRE before making, you can use --with-match-limit=n
836     to set a default value for the compiled library.
837    
838     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
839     a different value is set. See 45 below.
840    
841     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
842    
843     43. Added a new function pcre_config(int, void *) to enable run-time extraction
844     of things that can be changed at compile time. The first argument specifies
845     what is wanted and the second points to where the information is to be placed.
846     The current list of available information is:
847    
848     PCRE_CONFIG_UTF8
849    
850     The output is an integer that is set to one if UTF-8 support is available;
851     otherwise it is set to zero.
852    
853     PCRE_CONFIG_NEWLINE
854    
855     The output is an integer that it set to the value of the code that is used for
856     newline. It is either LF (10) or CR (13).
857    
858     PCRE_CONFIG_LINK_SIZE
859    
860     The output is an integer that contains the number of bytes used for internal
861     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
862    
863     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
864    
865     The output is an integer that contains the threshold above which the POSIX
866     interface uses malloc() for output vectors. See item 31 above.
867    
868     PCRE_CONFIG_MATCH_LIMIT
869    
870     The output is an unsigned integer that contains the default limit of the number
871     of match() calls in a pcre_exec() execution. See 42 above.
872    
873     44. pcretest has been upgraded by the addition of the -C option. This causes it
874     to extract all the available output from the new pcre_config() function, and to
875     output it. The program then exits immediately.
876    
877     45. A need has arisen to pass over additional data with calls to pcre_exec() in
878     order to support additional features. One way would have been to define
879     pcre_exec2() (for example) with extra arguments, but this would not have been
880     extensible, and would also have required all calls to the original function to
881     be mapped to the new one. Instead, I have chosen to extend the mechanism that
882     is used for passing in "extra" data from pcre_study().
883    
884     The pcre_extra structure is now exposed and defined in pcre.h. It currently
885     contains the following fields:
886    
887     flags a bitmap indicating which of the following fields are set
888     study_data opaque data from pcre_study()
889     match_limit a way of specifying a limit on match() calls for a specific
890     call to pcre_exec()
891     callout_data data for callouts (see 49 below)
892    
893     The flag bits are also defined in pcre.h, and are
894    
895     PCRE_EXTRA_STUDY_DATA
896     PCRE_EXTRA_MATCH_LIMIT
897     PCRE_EXTRA_CALLOUT_DATA
898    
899     The pcre_study() function now returns one of these new pcre_extra blocks, with
900     the actual study data pointed to by the study_data field, and the
901     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
902     before. That is, this change is entirely upwards-compatible and requires no
903     change to existing code.
904    
905     If you want to pass in additional data to pcre_exec(), you can either place it
906     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
907     block.
908    
909     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
910     data string contains the escape sequence \M, pcretest calls pcre_exec() several
911     times with different match limits, until it finds the minimum value needed for
912     pcre_exec() to complete. The value is then output. This can be instructive; for
913     most simple matches the number is quite small, but for pathological cases it
914     gets very large very quickly.
915    
916     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
917     returns the size of the data block pointed to by the study_data field in a
918     pcre_extra block, that is, the value that was passed as the argument to
919     pcre_malloc() when PCRE was getting memory in which to place the information
920     created by pcre_study(). The fourth argument should point to a size_t variable.
921     pcretest has been extended so that this information is shown after a successful
922     pcre_study() call when information about the compiled regex is being displayed.
923    
924     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
925     because what follows is always an absolute path. (Later: it turns out that this
926     is more than cosmetic for MinGW, because it doesn't like empty path
927     components.)
928    
929     49. Some changes have been made to the callout feature (see 28 above):
930    
931     (i) A callout function now has three choices for what it returns:
932    
933     0 => success, carry on matching
934     > 0 => failure at this point, but backtrack if possible
935     < 0 => serious error, return this value from pcre_exec()
936    
937     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
938     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
939     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
940     use by callout functions. It will never be used by PCRE itself.
941    
942     (ii) The pcre_extra structure (see 45 above) has a void * field called
943     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
944     pcre_callout_block structure has a field of the same name. The contents of
945     the field passed in the pcre_extra structure are passed to the callout
946     function in the corresponding field in the callout block. This makes it
947     easier to use the same callout-containing regex from multiple threads. For
948     testing, the pcretest program has a new data escape
949    
950     \C*n pass the number n (may be negative) as callout_data
951    
952     If the callout function in pcretest receives a non-zero value as
953     callout_data, it returns that value.
954    
955     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
956     there were some redundant $(CFLAGS) in commands that are now specified as
957     $(LINK), which already includes $(CFLAGS).
958    
959     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
960     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
961     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
962     one-byte characters throughout. Note that case-insensitive matching applies
963     only to characters whose values are less than 256. PCRE doesn't support the
964     notion of cases for higher-valued characters.
965    
966     (i) A character class whose characters are all within 0-255 is handled as
967     a bit map, and the map is inverted for negative classes. Previously, a
968     character > 255 always failed to match such a class; however it should
969     match if the class was a negative one (e.g. [^ab]). This has been fixed.
970    
971     (ii) A negated character class with a single character < 255 is coded as
972     "not this character" (OP_NOT). This wasn't working properly when the test
973     character was multibyte, either singly or repeated.
974    
975     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
976     mode, for example: \x{100}{2,3}.
977    
978     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
979     singly or repeated) now correctly test multibyte characters. However,
980     PCRE doesn't recognize any characters with values greater than 255 as
981     digits, spaces, or word characters. Such characters always match \D, \S,
982     and \W, and never match \d, \s, or \w.
983    
984     (v) Classes may now contain characters and character ranges with values
985     greater than 255. For example: [ab\x{100}-\x{400}].
986    
987     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
988     PCRE in UTF-8 mode.
989    
990     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
991     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
992     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
993     value.)
994    
995     53. The single man page has become too large. I have therefore split it up into
996     a number of separate man pages. These also give rise to individual HTML pages;
997     these are now put in a separate directory, and there is an index.html page that
998     lists them all. Some hyperlinking between the pages has been installed.
999    
1000     54. Added convenience functions for handling named capturing parentheses.
1001    
1002     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1003     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1004     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1005     are faulted.
1006    
1007     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1008     calling configure. These values are used when compiling the dftables.c program
1009     which is run to generate the source of the default character tables. They
1010     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1011     you will need to set these values.
1012    
1013     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1014    
1015    
1016     Version 3.9 02-Jan-02
1017 nigel 61 ---------------------
1018    
1019     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1020    
1021     2. If --disable-static was given, the building process failed when trying to
1022     build pcretest and pcregrep. (For some reason it was using libtool to compile
1023     them, which is not right, as they aren't part of the library.)
1024    
1025    
1026 nigel 59 Version 3.8 18-Dec-01
1027     ---------------------
1028    
1029     1. The experimental UTF-8 code was completely screwed up. It was packing the
1030     bytes in the wrong order. How dumb can you get?
1031    
1032    
1033 nigel 57 Version 3.7 29-Oct-01
1034     ---------------------
1035    
1036     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1037     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1038     this didn't happen under Solaris 8, where I normally test things.
1039    
1040 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1041     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1042     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1043     this fix an hour or so after the initial 3.7 release.)
1044 nigel 57
1045 nigel 59
1046 nigel 55 Version 3.6 23-Oct-01
1047     ---------------------
1048    
1049     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1050     offsets passed as NULL with zero offset count.
1051    
1052     2. The config.guess and config.sub files had not been updated when I moved to
1053     the latest autoconf.
1054    
1055    
1056 nigel 53 Version 3.5 15-Aug-01
1057     ---------------------
1058 nigel 5
1059 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1060     had been forgotten.
1061    
1062     2. By using declared but undefined structures, we can avoid using "void"
1063     definitions in pcre.h while keeping the internal definitions of the structures
1064     private.
1065    
1066     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1067     user point of view, this means that both static and shared libraries are built
1068     by default, but this can be individually controlled. More of the work of
1069     handling this static/shared cases is now inside libtool instead of PCRE's make
1070     file.
1071    
1072     4. The pcretest utility is now installed along with pcregrep because it is
1073     useful for users (to test regexs) and by doing this, it automatically gets
1074     relinked by libtool. The documentation has been turned into a man page, so
1075     there are now .1, .txt, and .html versions in /doc.
1076    
1077     5. Upgrades to pcregrep:
1078     (i) Added long-form option names like gnu grep.
1079     (ii) Added --help to list all options with an explanatory phrase.
1080     (iii) Added -r, --recursive to recurse into sub-directories.
1081     (iv) Added -f, --file to read patterns from a file.
1082    
1083     6. pcre_exec() was referring to its "code" argument before testing that
1084     argument for NULL (and giving an error if it was NULL).
1085    
1086     7. Upgraded Makefile.in to allow for compiling in a different directory from
1087     the source directory.
1088    
1089     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1090     options bits, the pointer it was passed was to an int instead of to an unsigned
1091     long int. This mattered only on 64-bit systems.
1092    
1093     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1094     generated) instead of pcre.in, which it its source. Also made the same change
1095     in several of the .c files.
1096    
1097     10. A new release of gcc defines printf() as a macro, which broke pcretest
1098     because it had an ifdef in the middle of a string argument for printf(). Fixed
1099     by using separate calls to printf().
1100    
1101     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1102     script, to force use of CR or LF instead of \n in the source. On non-Unix
1103     systems, the value can be set in config.h.
1104    
1105     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1106     absolute limit. Changed the text of the error message to make this clear, and
1107     likewise updated the man page.
1108    
1109     13. The limit of 99 on the number of capturing subpatterns has been removed.
1110     The new limit is 65535, which I hope will not be a "real" limit.
1111    
1112    
1113 nigel 51 Version 3.4 22-Aug-00
1114     ---------------------
1115    
1116     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1117    
1118     2. Diagnose condition (?(0) as an error instead of crashing on matching.
1119    
1120    
1121 nigel 49 Version 3.3 01-Aug-00
1122     ---------------------
1123    
1124     1. If an octal character was given, but the value was greater than \377, it
1125     was not getting masked to the least significant bits, as documented. This could
1126     lead to crashes in some systems.
1127    
1128     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
1129     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
1130    
1131     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
1132     These just pass their arguments on to (pcre_free)(), but they are provided
1133     because some uses of PCRE bind it to non-C systems that can call its functions,
1134     but cannot call free() or pcre_free() directly.
1135    
1136     4. Add "make test" as a synonym for "make check". Corrected some comments in
1137     the Makefile.
1138    
1139     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
1140     Makefile.
1141    
1142     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
1143     command called pgrep for grepping around the active processes.
1144    
1145     7. Added the beginnings of support for UTF-8 character strings.
1146    
1147     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
1148     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
1149     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
1150     out for the ar command.)
1151    
1152    
1153 nigel 47 Version 3.2 12-May-00
1154     ---------------------
1155    
1156     This is purely a bug fixing release.
1157    
1158     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
1159     of ZA. This was just one example of several cases that could provoke this bug,
1160     which was introduced by change 9 of version 2.00. The code for breaking
1161     infinite loops after an iteration that matches an empty string was't working
1162     correctly.
1163    
1164     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
1165     when matched against abbab (for example). After matching an empty string, it
1166     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
1167     caused it to match further down the string than it should.
1168    
1169     3. The code contained an inclusion of sys/types.h. It isn't clear why this
1170     was there because it doesn't seem to be needed, and it causes trouble on some
1171     systems, as it is not a Standard C header. It has been removed.
1172    
1173     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
1174     were reported on the Macintosh. The changes were from
1175    
1176     while ((c = *(++ptr)) != 0 && c != '\n');
1177     to
1178     while ((c = *(++ptr)) != 0 && c != '\n') ;
1179    
1180     Totally extraordinary, but if that's what it takes...
1181    
1182     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
1183     available. Added HAVE_BCOPY and an autoconf test for it; if neither
1184     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
1185     assumes the way PCRE uses memmove() (always moving upwards).
1186    
1187     6. PCRE is being used in one environment where strchr() is not available. There
1188     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
1189     faster code anyway.
1190    
1191    
1192 nigel 45 Version 3.1 09-Feb-00
1193     ---------------------
1194    
1195     The only change in this release is the fixing of some bugs in Makefile.in for
1196     the "install" target:
1197    
1198     (1) It was failing to install pcreposix.h.
1199    
1200     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
1201    
1202    
1203 nigel 43 Version 3.0 01-Feb-00
1204     ---------------------
1205 nigel 41
1206     1. Add support for the /+ modifier to perltest (to output $` like it does in
1207     pcretest).
1208    
1209     2. Add support for the /g modifier to perltest.
1210    
1211     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
1212     matches null strings.
1213    
1214     4. Fix perltest so that it doesn't do unwanted things when fed an empty
1215     pattern. Perl treats empty patterns specially - it reuses the most recent
1216     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
1217     effect.
1218    
1219     5. The POSIX interface was broken in that it was just handing over the POSIX
1220     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
1221     required a bigger vector, with some working space on the end. This means that
1222     the POSIX wrapper now has to get and free some memory, and copy the results.
1223    
1224 nigel 43 6. Added some simple autoconf support, placing the test data and the
1225     documentation in separate directories, re-organizing some of the
1226     information files, and making it build pcre-config (a GNU standard). Also added
1227     libtool support for building PCRE as a shared library, which is now the
1228     default.
1229 nigel 41
1230 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
1231     09 are not valid octal constants. Single digits will be used for minor values
1232     less than 10.
1233    
1234     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
1235     existing programs that set these in the POSIX interface can use PCRE without
1236     modification.
1237    
1238     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
1239     return all that pcre_info() returns, plus additional data. The pcre_info()
1240     function is retained for compatibility, but is considered to be obsolete.
1241    
1242     10. Added experimental recursion feature (?R) to handle one common case that
1243     Perl 5.6 will be able to do with (?p{...}).
1244    
1245     11. Added support for POSIX character classes like [:alpha:], which Perl is
1246     adopting.
1247    
1248    
1249 nigel 39 Version 2.08 31-Aug-99
1250     ----------------------
1251    
1252     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
1253     trying to match at the startoffset position, but instead was moving forward to
1254     the next newline as if a previous match had failed.
1255    
1256     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
1257     and could get into a loop if a null string was matched other than at the start
1258     of the subject.
1259    
1260     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
1261     be distinguished at compile time, and for completeness also added PCRE_DATE.
1262    
1263     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
1264     in GnuWin32 environments.
1265    
1266    
1267 nigel 37 Version 2.07 29-Jul-99
1268     ----------------------
1269    
1270     1. The documentation is now supplied in plain text form and HTML as well as in
1271     the form of man page sources.
1272    
1273     2. C++ compilers don't like assigning (void *) values to other pointer types.
1274     In particular this affects malloc(). Although there is no problem in Standard
1275     C, I've put in casts to keep C++ compilers happy.
1276    
1277     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
1278     should be (const char *).
1279    
1280     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
1281     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
1282     However, I haven't made this a standard facility. The documentation doesn't
1283     mention it, and the Makefile doesn't support it.
1284    
1285     5. The Makefile now contains an "install" target, with editable destinations at
1286     the top of the file. The pcretest program is not installed.
1287    
1288     6. pgrep -V now gives the PCRE version number and date.
1289    
1290     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
1291     causing the entire string to be ignored, instead of just the last character.
1292    
1293     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
1294     non-matching string, it can take a very, very long time, even for strings of
1295     quite modest length, because of the nested recursion. PCRE now does better in
1296     some of these cases. It does this by remembering the last required literal
1297     character in the pattern, and pre-searching the subject to ensure it is present
1298     before running the real match. In other words, it applies a heuristic to detect
1299     some types of certain failure quickly, and in the above example, if presented
1300     with a string that has no trailing " it gives "no match" very quickly.
1301    
1302     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
1303     other alternatives are tried instead.
1304    
1305    
1306 nigel 35 Version 2.06 09-Jun-99
1307     ----------------------
1308    
1309     1. Change pcretest's output for amount of store used to show just the code
1310     space, because the remainder (the data block) varies in size between 32-bit and
1311     64-bit systems.
1312    
1313     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
1314     start matching at. This allows lookbehinds to work when searching for multiple
1315     occurrences in a string.
1316    
1317     3. Added additional options to pcretest for testing multiple occurrences:
1318    
1319     /+ outputs the rest of the string that follows a match
1320     /g loops for multiple occurrences, using the new startoffset argument
1321     /G loops for multiple occurrences by passing an incremented pointer
1322    
1323     4. PCRE wasn't doing the "first character" optimization for patterns starting
1324     with \b or \B, though it was doing it for other lookbehind assertions. That is,
1325     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
1326     the letter 'x'. On long subject strings, this gives a significant speed-up.
1327    
1328    
1329 nigel 33 Version 2.05 21-Apr-99
1330     ----------------------
1331    
1332     1. Changed the type of magic_number from int to long int so that it works
1333     properly on 16-bit systems.
1334    
1335     2. Fixed a bug which caused patterns starting with .* not to work correctly
1336     when the subject string contained newline characters. PCRE was assuming
1337     anchoring for such patterns in all cases, which is not correct because .* will
1338     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
1339     DOTALL is set at top level; otherwise it knows that patterns starting with .*
1340     must be retried after every newline in the subject.
1341    
1342    
1343 nigel 31 Version 2.04 18-Feb-99
1344     ----------------------
1345    
1346     1. For parenthesized subpatterns with repeats whose minimum was zero, the
1347     computation of the store needed to hold the pattern was incorrect (too large).
1348     If such patterns were nested a few deep, this could multiply and become a real
1349     problem.
1350    
1351     2. Added /M option to pcretest to show the memory requirement of a specific
1352     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
1353    
1354     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
1355     compiled in such a way that the backtracking after subsequent failure was
1356     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
1357     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
1358    
1359    
1360 nigel 29 Version 2.03 02-Feb-99
1361     ----------------------
1362    
1363     1. Fixed typo and small mistake in man page.
1364    
1365 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
1366     LICENCE file containing the conditions.
1367 nigel 29
1368     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
1369     Perl, that is the internal \ allows the delimiter to be included in the
1370     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
1371     the final delimiter, add \ to the end of the pattern (to test the error).
1372    
1373     4. Added the convenience functions for extracting substrings after a successful
1374     match. Updated pcretest to make it able to test these functions.
1375    
1376    
1377 nigel 27 Version 2.02 14-Jan-99
1378     ----------------------
1379    
1380     1. Initialized the working variables associated with each extraction so that
1381     their saving and restoring doesn't refer to uninitialized store.
1382    
1383     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
1384     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
1385     fix the problem.
1386    
1387     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
1388     calls, and wasn't printing the correct value for compiling calls. Increased the
1389     default value of LOOPREPEAT, and the number of significant figures in the
1390     times.
1391    
1392     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
1393    
1394     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
1395     a building problem on Windows NT with a FAT file system.
1396    
1397    
1398 nigel 25 Version 2.01 21-Oct-98
1399     ----------------------
1400    
1401     1. Changed the API for pcre_compile() to allow for the provision of a pointer
1402     to character tables built by pcre_maketables() in the current locale. If NULL
1403     is passed, the default tables are used.
1404    
1405    
1406 nigel 23 Version 2.00 24-Sep-98
1407 nigel 21 ----------------------
1408    
1409 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
1410     it any more.
1411    
1412     2. Allow quantification of (?>) groups, and make it work correctly.
1413    
1414     3. The first character computation wasn't working for (?>) groups.
1415    
1416     4. Correct the implementation of \Z (it is permitted to match on the \n at the
1417     end of the subject) and add 5.005's \z, which really does match only at the
1418     very end of the subject.
1419    
1420     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
1421    
1422     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
1423     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
1424     localized options. All options to pcre_study() were also removed.
1425    
1426     7. Add other new features from 5.005:
1427    
1428     $(?<= positive lookbehind
1429     $(?<! negative lookbehind
1430     (?imsx-imsx) added the unsetting capability
1431     such a setting is global if at outer level; local otherwise
1432     (?imsx-imsx:) non-capturing groups with option setting
1433     (?(cond)re|re) conditional pattern matching
1434    
1435     A backreference to itself in a repeated group matches the previous
1436     captured string.
1437    
1438     8. General tidying up of studying (both automatic and via "study")
1439     consequential on the addition of new assertions.
1440    
1441     9. As in 5.005, unlimited repeated groups that could match an empty substring
1442     are no longer faulted at compile time. Instead, the loop is forcibly broken at
1443     runtime if any iteration does actually match an empty substring.
1444    
1445     10. Include the RunTest script in the distribution.
1446    
1447     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
1448     discrepancies, some of which were old and were also with respect to 5.004. They
1449     have now been fixed.
1450    
1451    
1452     Version 1.09 28-Apr-98
1453     ----------------------
1454    
1455 nigel 21 1. A negated single character class followed by a quantifier with a minimum
1456     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
1457     program crashes, or just wrong answers. This did not apply to negated classes
1458     containing more than one character, or to minima other than one.
1459    
1460    
1461 nigel 19 Version 1.08 27-Mar-98
1462     ----------------------
1463    
1464     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
1465    
1466     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
1467     latter must appear before anything that relies on it in the pattern.
1468    
1469    
1470 nigel 17 Version 1.07 16-Feb-98
1471     ----------------------
1472    
1473     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
1474     repeat of a potentially empty string).
1475    
1476    
1477 nigel 15 Version 1.06 23-Jan-98
1478     ----------------------
1479    
1480     1. Added Markus Oberhumer's little patches for C++.
1481    
1482     2. Literal strings longer than 255 characters were broken.
1483    
1484    
1485 nigel 13 Version 1.05 23-Dec-97
1486     ----------------------
1487    
1488     1. Negated character classes containing more than one character were failing if
1489     PCRE_CASELESS was set at run time.
1490    
1491    
1492 nigel 11 Version 1.04 19-Dec-97
1493     ----------------------
1494    
1495     1. Corrected the man page, where some "const" qualifiers had been omitted.
1496    
1497     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
1498     input syntax.
1499    
1500     3. Fixed memory leak which occurred when a regex with back references was
1501     matched with an offsets vector that wasn't big enough. The temporary memory
1502     that is used in this case wasn't being freed if the match failed.
1503    
1504     4. Tidied pcretest to ensure it frees memory that it gets.
1505    
1506     5. Temporary memory was being obtained in the case where the passed offsets
1507     vector was exactly big enough.
1508    
1509     6. Corrected definition of offsetof() from change 5 below.
1510    
1511     7. I had screwed up change 6 below and broken the rules for the use of
1512     setjmp(). Now fixed.
1513    
1514    
1515 nigel 9 Version 1.03 18-Dec-97
1516     ----------------------
1517    
1518     1. A erroneous regex with a missing opening parenthesis was correctly
1519     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
1520     on some systems.
1521    
1522     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
1523     it was reported that one broken compiler failed on the former because "code" is
1524     also an independent variable.
1525    
1526     3. The erroneous regex a[]b caused an array overrun reference.
1527    
1528     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
1529     fail on data ending with that character. (It was going on too far, and checking
1530     the next character, typically a binary zero.) This was specific to the
1531     optimized code for single-character negative classes.
1532    
1533     5. Added a contributed patch from the TIN world which does the following:
1534    
1535     + Add an undef for memmove, in case the the system defines a macro for it.
1536    
1537     + Add a definition of offsetof(), in case there isn't one. (I don't know
1538     the reason behind this - offsetof() is part of the ANSI standard - but
1539     it does no harm).
1540    
1541     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
1542     most of the places where whitespace preceded '#'. I have given up and
1543     allowed the remaining 2 cases to be at the margin.
1544    
1545     + Rename some variables in pcre to eliminate shadowing. This seems very
1546     pedantic, but does no harm, of course.
1547    
1548     6. Moved the call to setjmp() into its own function, to get rid of warnings
1549     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
1550    
1551     7. Constructs such as \d{8,} were compiling into the equivalent of
1552 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
1553 nigel 9 outcome, but in this particular case used more store than had been allocated,
1554     which caused the bug to be discovered because it threw up an internal error.
1555    
1556     8. The debugging code in both pcre and pcretest for outputting the compiled
1557     form of a regex was going wrong in the case of back references followed by
1558     curly-bracketed repeats.
1559    
1560    
1561 nigel 7 Version 1.02 12-Dec-97
1562     ----------------------
1563    
1564     1. Typos in pcre.3 and comments in the source fixed.
1565    
1566     2. Applied a contributed patch to get rid of places where it used to remove
1567     'const' from variables, and fixed some signed/unsigned and uninitialized
1568     variable warnings.
1569    
1570     3. Added the "runtest" target to Makefile.
1571    
1572     4. Set default compiler flag to -O2 rather than just -O.
1573    
1574    
1575 nigel 5 Version 1.01 19-Nov-97
1576     ----------------------
1577    
1578     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
1579     like /([ab]*)*/, that is, for classes with more than one character in them.
1580    
1581     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
1582     as /((?>a*))*/ (a PCRE_EXTRA facility).
1583    
1584    
1585     Version 1.00 18-Nov-97
1586     ----------------------
1587    
1588     1. Added compile-time macros to support systems such as SunOS4 which don't have
1589     memmove() or strerror() but have other things that can be used instead.
1590    
1591     2. Arranged that "make clean" removes the executables.
1592    
1593    
1594 nigel 3 Version 0.99 27-Oct-97
1595     ----------------------
1596    
1597     1. Fixed bug in code for optimizing classes with only one character. It was
1598     initializing a 32-byte map regardless, which could cause it to run off the end
1599     of the memory it had got.
1600    
1601     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
1602    
1603    
1604     Version 0.98 22-Oct-97
1605     ----------------------
1606    
1607     1. Fixed bug in code for handling temporary memory usage when there are more
1608     back references than supplied space in the ovector. This could cause segfaults.
1609    
1610    
1611     Version 0.97 21-Oct-97
1612     ----------------------
1613    
1614     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
1615    
1616     2. Optimized negated single characters not to use a bit map.
1617    
1618     3. Brought error texts together as macro definitions; clarified some of them;
1619     fixed one that was wrong - it said "range out of order" when it meant "invalid
1620     escape sequence".
1621    
1622     4. Changed some char * arguments to const char *.
1623    
1624     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
1625    
1626     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
1627     pcretest.
1628    
1629    
1630     Version 0.96 16-Oct-97
1631     ----------------------
1632    
1633     1. Added a simple "pgrep" utility to the distribution.
1634    
1635     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
1636     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
1637     where "ddd" means "one or more decimal digits".
1638    
1639     3. Fixed serious bug. If a pattern had a back reference, but the call to
1640     pcre_exec() didn't supply a large enough ovector to record the related
1641     identifying subpattern, the match always failed. PCRE now remembers the number
1642     of the largest back reference, and gets some temporary memory in which to save
1643     the offsets during matching if necessary, in order to ensure that
1644     backreferences always work.
1645    
1646     4. Increased the compatibility with Perl in a number of ways:
1647    
1648     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
1649     to request this handling. The option can be set at compile or exec time.
1650    
1651     (b) $ matches before a terminating newline by default; an option
1652     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
1653     mode). The option can be set at compile or exec time.
1654    
1655     (c) The handling of \ followed by a digit other than 0 is now supposed to be
1656     the same as Perl's. If the decimal number it represents is less than 10
1657     or there aren't that many previous left capturing parentheses, an octal
1658     escape is read. Inside a character class, it's always an octal escape,
1659     even if it is a single digit.
1660    
1661     (d) An escaped but undefined alphabetic character is taken as a literal,
1662     unless PCRE_EXTRA is set. Currently this just reserves the remaining
1663     escapes.
1664    
1665     (e) {0} is now permitted. (The previous item is removed from the compiled
1666     pattern).
1667    
1668     5. Changed all the names of code files so that the basic parts are no longer
1669     than 10 characters, and abolished the teeny "globals.c" file.
1670    
1671     6. Changed the handling of character classes; they are now done with a 32-byte
1672     bit map always.
1673    
1674     7. Added the -d and /D options to pcretest to make it possible to look at the
1675     internals of compilation without having to recompile pcre.
1676    
1677    
1678     Version 0.95 23-Sep-97
1679     ----------------------
1680    
1681     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
1682     \x20 at the start of a run of normal characters. These were being treated as
1683     real characters, instead of the source characters being re-checked.
1684    
1685    
1686     Version 0.94 18-Sep-97
1687     ----------------------
1688    
1689     1. The functions are now thread-safe, with the caveat that the global variables
1690     containing pointers to malloc() and free() or alternative functions are the
1691     same for all threads.
1692    
1693     2. Get pcre_study() to generate a bitmap of initial characters for non-
1694     anchored patterns when this is possible, and use it if passed to pcre_exec().
1695    
1696    
1697     Version 0.93 15-Sep-97
1698     ----------------------
1699    
1700     1. /(b)|(:+)/ was computing an incorrect first character.
1701    
1702     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
1703     but not actually doing anything yet.
1704    
1705     3. Treat "-" characters in classes that cannot be part of ranges as literals,
1706     as Perl does (e.g. [-az] or [az-]).
1707    
1708     4. Set the anchored flag if a branch starts with .* or .*? because that tests
1709     all possible positions.
1710    
1711     5. Split up into different modules to avoid including unneeded functions in a
1712     compiled binary. However, compile and exec are still in one module. The "study"
1713     function is split off.
1714    
1715     6. The character tables are now in a separate module whose source is generated
1716     by an auxiliary program - but can then be edited by hand if required. There are
1717     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
1718     toupper() in the code.
1719    
1720     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
1721     make them global. Abolish the function for setting them, as the caller can now
1722     set them directly.
1723    
1724    
1725     Version 0.92 11-Sep-97
1726     ----------------------
1727    
1728     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
1729     (e.g. /a{1,3}/) was broken (I mis-optimized it).
1730    
1731     2. Caseless matching was not working in character classes if the characters in
1732     the pattern were in upper case.
1733    
1734     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
1735    
1736     4. Make PCRE_ANCHORED public and accept as a compile option.
1737    
1738     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
1739     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
1740     pass them.
1741    
1742     6. Give an error if bad option bits passed at compile or run time.
1743    
1744     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
1745     pcretest to cause it to pass that flag.
1746    
1747     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
1748     options, and the first character, if set.
1749    
1750     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
1751    
1752    
1753     Version 0.91 10-Sep-97
1754     ----------------------
1755    
1756     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
1757     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
1758    
1759     2. PCRE was looping on encountering an indefinitely repeated back reference to
1760     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
1761     Perl does - treats the match as successful.
1762    
1763     ****

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