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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 6.0 07-Jun-05
5    ---------------------
7     1. Some minor internal re-organization to help with my DFA experiments.
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.
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.
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.
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.
33     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
34        including restarting after a partial match.
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.
40     7. Added the pcre_refcount() auxiliary function.
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.
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.
49    10. A number of changes to the pcregrep command:
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.
55        (b) Added the -w (match as a word) option.
57        (c) Refactored the way lines are read and buffered so as to have more
58            than one at a time available.
60        (d) Implemented a pcregrep test script.
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).
67        (f) Changed the --help output so that it now says
69              -w, --word-regex(p)
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.)
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.
80        (h) "-" can be given as a file name to represent stdin.
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.
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.
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".
93        (l) Added the -A, -B, and -C options for requesting that lines of context
94            around matches be printed.
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.
99        (n) The return code is 2 if any file cannot be opened, but pcregrep does
100            continue to scan other files.
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.
108        (p) Added --include and --exclude options to specify files for inclusion
109            and exclusion when recursing.
111    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
112        Hopefully, it now does.
114    12. Missing cast in pcre_study().
116    13. Added an "uninstall" target to the makefile.
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.
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.
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.)
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.
142    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
144    19. libpcre.pc was being incorrectly installed as executable.
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.
149    21. Added Google's contributed C++ wrapper to the distribution.
151    22. Added some untidy missing memory free() calls in pcretest, to keep
152        Electric Fence happy when testing.
156    Version 5.0 13-Sep-04
157    ---------------------
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.
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.
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.
172     4. On the advice of a Windows user, the lines
174          #if defined(_WIN32) || defined(WIN32)
175          _setmode( _fileno( stdout ), 0x8000 );
176          #endif  /* defined(_WIN32) || defined(WIN32) */
178        have been added to the source of pcretest. This apparently does useful
179        magic in relation to line terminators.
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.
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.)
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.
196     7. Added support for pkg-config (2 patches were sent in).
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.
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.
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.
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.)
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.
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.
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.
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.
235    16. Updated pcredemo.c to include calls to free() to release the memory for the
236        compiled pattern.
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.
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.
247    19. Added support for partial matching via the PCRE_PARTIAL option for
248        pcre_exec() and the \P data escape in pcretest.
250    20. Extended pcretest with 3 new pattern features:
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.
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.
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.
269    21. The pcre-exec() function can now cope with patterns that were compiled on
270        hosts of opposite endianness, with this restriction:
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.
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.
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).
289    24. Changed the PCRE licence to be the more standard "BSD" licence.
292    Version 4.5 01-Dec-03
293    ---------------------
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.
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.
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.
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.
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.
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.
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".
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.
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").
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".
346     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
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.
352    10. Added some adjustments to the code to make it easier to compiler on certain
353        special systems:
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.
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.
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.
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.
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.
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.
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.
391    Version 4.4 13-Aug-03
392    ---------------------
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).
399     2. Three internal functions had redundant arguments passed to them. Removal
400        might give a very teeny performance improvement.
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.
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.
409     5. configure.in no longer needs to recognize Cygwin specially.
411     6. A problem in pcre.in for Windows platforms is fixed.
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.
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.
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.
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.
436    11. In response to a bug report, I changed one line in Makefile.in from
438            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
439        to
440            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
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...
447    Version 4.3 21-May-03
448    ---------------------
450    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
451       Makefile.
453    2. Some refactoring to improve the quality of the code:
455       (i)   The utf8_table... variables are now declared "const".
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.
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.
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.
474    3. The first argument for regexec() in the POSIX wrapper should have been
475       defined as "const".
477    4. Changed pcretest to use malloc() for its buffers so that they can be
478       Electric Fenced for debugging.
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.
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.
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.)
495    Version 4.2 14-Apr-03
496    ---------------------
498    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
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
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.
529    3. Some tidies to get rid of compiler warnings:
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.
534       . In pcretest the fact that a const uschar * doesn't automatically cast to
535         a void * provoked a warning.
537       . Turning on some more compiler warnings threw up some "shadow" variables
538         and a few more missing casts.
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.
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.
549    Version 4.1 12-Mar-03
550    ---------------------
552    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.
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.
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.
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.
569    5. PCRE was failing to diagnose the case of two named groups with the same
570    name.
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.
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/.
589    Version 4.0 17-Feb-03
590    ---------------------
592    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.
596    2. Moved to autoconf 2.53 and libtool 1.4.2.
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.
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.
607    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
608    space and tab.
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.
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.
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:
625        Pattern            PCRE matches      Perl matches
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
631    For compatibility with Perl, \Q...\E sequences are recognized inside character
632    classes as well as outside them.
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.
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.
643    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
644    "pcregrep -".
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.
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.
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.
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.
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:]]/).
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.
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.
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/.
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/.
693    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
694    compiling PCRE for use with Virtual Pascal.
696    22. Small fix to the Makefile to make it work properly if the build is done
697    outside the source tree.
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.
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.
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.)
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.
721    27. Fixed typo in error message for invalid (?R item (it said "(?p").
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.]
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:
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
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.
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.
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.
764    33. Internal code re-arrangements:
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.
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.
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.
778    34. Added support for recursive calls to individual subpatterns, along the
779    lines of Robin Houston's patch (but implemented somewhat differently).
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.
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:
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.
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.
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.
805    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
806    calling malloc() with a zero argument.
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.
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).
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.
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:
835    (a) When configuring PCRE before making, you can use --with-match-limit=n
836        to set a default value for the compiled library.
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.
841    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
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:
850    The output is an integer that is set to one if UTF-8 support is available;
851    otherwise it is set to zero.
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).
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.
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.
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.
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.
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().
884    The pcre_extra structure is now exposed and defined in pcre.h. It currently
885    contains the following fields:
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)
893    The flag bits are also defined in pcre.h, and are
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.
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.
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.
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.
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.)
929    49. Some changes have been made to the callout feature (see 28 above):
931    (i)  A callout function now has three choices for what it returns:
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()
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.
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
950           \C*n        pass the number n (may be negative) as callout_data
952         If the callout function in pcretest receives a non-zero value as
953         callout_data, it returns that value.
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).
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.
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.
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.
975    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
976          mode, for example: \x{100}{2,3}.
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.
984    (v)   Classes may now contain characters and character ranges with values
985          greater than 255. For example: [ab\x{100}-\x{400}].
987    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
988          PCRE in UTF-8 mode.
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.)
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.
1000    54. Added convenience functions for handling named capturing parentheses.
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.
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.
1013    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1016    Version 3.9 02-Jan-02
1017    ---------------------
1019    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
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.)
1026    Version 3.8 18-Dec-01
1027    ---------------------
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?
1033    Version 3.7 29-Oct-01
1034    ---------------------
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.
1040    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.)
1046    Version 3.6 23-Oct-01
1047    ---------------------
1049    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1050    offsets passed as NULL with zero offset count.
1052    2. The config.guess and config.sub files had not been updated when I moved to
1053    the latest autoconf.
1056    Version 3.5 15-Aug-01
1057    ---------------------
1059    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1060    had been forgotten.
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.
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.
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.
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.
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).
1086    7. Upgraded Makefile.in to allow for compiling in a different directory from
1087    the source directory.
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.
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.
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().
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.
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.
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.
1113    Version 3.4 22-Aug-00
1114    ---------------------
1116    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1118    2. Diagnose condition (?(0) as an error instead of crashing on matching.
1121  Version 3.3 01-Aug-00  Version 3.3 01-Aug-00
1122  ---------------------  ---------------------

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