\ UTF-8 handling                                       12dec04py

\ Copyright (C) 2004,2005,2006 Free Software Foundation, Inc.

\ This file is part of Gforth.

\ Gforth is free software; you can redistribute it and/or
\ modify it under the terms of the GNU General Public License
\ as published by the Free Software Foundation; either version 2
\ of the License, or (at your option) any later version.

\ This program is distributed in the hope that it will be useful,
\ but WITHOUT ANY WARRANTY; without even the implied warranty of
\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
\ GNU General Public License for more details.

\ You should have received a copy of the GNU General Public License
\ along with this program; if not, write to the Free Software
\ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.

\ short: u8 means utf-8 encoded address

s" malformed UTF-8 character" exception Constant UTF-8-err

$80 Value max-single-byte

: u8len ( u8 -- n )
    dup      max-single-byte u< IF  drop 1  EXIT  THEN \ special case ASCII
    $800  2 >r
    BEGIN  2dup u>=  WHILE  5 lshift r> 1+ >r  dup 0= UNTIL  THEN
    2drop r> ;

: u8@+ ( u8addr -- u8addr' u )
    count  dup max-single-byte u< ?EXIT  \ special case ASCII
    dup $C2 u< IF  UTF-8-err throw  THEN  \ malformed character
    $7F and  $40 >r
    BEGIN  dup r@ and  WHILE  r@ xor
	    6 lshift r> 5 lshift >r >r count
	    dup $C0 and $80 <> IF   UTF-8-err throw  THEN
	    $3F and r> or
    REPEAT  rdrop ;

: u8!+ ( u u8addr -- u8addr' )
    over max-single-byte u< IF  tuck c! 1+  EXIT  THEN \ special case ASCII
    >r 0 swap  $3F
    BEGIN  2dup u>  WHILE
	    2/ >r  dup $3F and $80 or swap 6 rshift r>
    REPEAT  $7F xor 2* or  r>
    BEGIN   over $80 u>= WHILE  tuck c! 1+  REPEAT  nip ;

\ plug-in so that char and '<char> work for UTF-8

[ifundef] char@ \ !! bootstrapping help
    Defer char@ ( addr u -- char addr' u' )
    :noname  over c@ -rot 1 /string ; IS char@
[then]

:noname  ( addr u -- char addr' u' )
    \ !! the if here seems to work around some breakage, but not
    \ entirely; e.g., try 'ç' with LANG=C.
    dup 1 u<= IF defers char@ EXIT THEN
    over + >r u8@+ swap r> over - ; IS char@

\ scan to next/previous character

\ alternative names: u8char+ u8char-

: u8>> ( u8addr -- u8addr' )  u8@+ drop ;
: u8<< ( u8addr -- u8addr' )
    BEGIN  1- dup c@ $C0 and max-single-byte <>  UNTIL ;

\ utf key and emit

Defer check-xy  ' noop IS check-xy

: u8key ( -- u )
    defers key dup max-single-byte u< ?EXIT  \ special case ASCII
    dup $FF = ?EXIT  \ special resize character
    dup $C2 u< IF  UTF-8-err throw  THEN  \ malformed character
    $7F and  $40 >r
    BEGIN  dup r@ and  WHILE  r@ xor
	    6 lshift r> 5 lshift >r >r defers key
	    dup $C0 and $80 <> IF  UTF-8-err throw  THEN
	    $3F and r> or
    REPEAT  rdrop ;

: u8emit ( u -- )
    dup max-single-byte u< IF  defers emit  EXIT  THEN \ special case ASCII
    0 swap  $3F
    BEGIN  2dup u>  WHILE
	    2/ >r  dup $3F and $80 or swap 6 rshift r>
    REPEAT  $7F xor 2* or
    BEGIN   dup $80 u>= WHILE  defers emit  REPEAT  drop ;

\ utf-8 stuff for xchars

: u8string+ ( xcaddr u -- xcaddr u' )
    over + u8>> over - ;
: u8string- ( xcaddr u -- xcaddr u' )
    over + u8<< over - ;

: +u8string ( xc-addr1 u1 -- xc-addr2 u2 )
    over dup u8>> swap - /string ;
: -u8string ( xc-addr1 u1 -- xc-addr2 u2 )
    over dup u8<< swap - /string ;

: u8@ ( c-addr -- u )
    u8@+ nip ;

: u8!+? ( xc xc-addr1 u1 -- xc-addr2 u2 f )
    >r over u8len r@ over u< if ( xc xc-addr1 len r: u1 )
	\ not enough space
	drop nip r> false
    else
	>r u8!+ r> r> swap - true
    then ;

: u8addrlen ( u8-addr -- u )
    \ length of UTF-8 char starting at u8-addr (accesses only u8-addr)
    c@
    dup $80 u< if drop 1 exit endif
    dup $c0 u< if UTF-8-err throw endif
    dup $e0 u< if drop 2 exit endif
    dup $f0 u< if drop 3 exit endif
    dup $f8 u< if drop 4 exit endif
    dup $fc u< if drop 5 exit endif
    dup $fe u< if drop 6 exit endif
    UTF-8-err throw ;

: -u8trailing-garbage ( addr u1 -- addr u2 )
    2dup + dup u8<< ( addr u1 end1 end2 )
    2dup dup u8addrlen + = if \ last character ok
	2drop
    else
	nip nip over -
    then ;

[IFUNDEF] wcwidth
: wc,3 ( n low high -- )  1+ , , , ;

Create wc-table \ derived from wcwidth source code, for UCS32
0 0300 0357 wc,3
0 035D 036F wc,3
0 0483 0486 wc,3
0 0488 0489 wc,3
0 0591 05A1 wc,3
0 05A3 05B9 wc,3
0 05BB 05BD wc,3
0 05BF 05BF wc,3
0 05C1 05C2 wc,3
0 05C4 05C4 wc,3
0 0600 0603 wc,3
0 0610 0615 wc,3
0 064B 0658 wc,3
0 0670 0670 wc,3
0 06D6 06E4 wc,3
0 06E7 06E8 wc,3
0 06EA 06ED wc,3
0 070F 070F wc,3
0 0711 0711 wc,3
0 0730 074A wc,3
0 07A6 07B0 wc,3
0 0901 0902 wc,3
0 093C 093C wc,3
0 0941 0948 wc,3
0 094D 094D wc,3
0 0951 0954 wc,3
0 0962 0963 wc,3
0 0981 0981 wc,3
0 09BC 09BC wc,3
0 09C1 09C4 wc,3
0 09CD 09CD wc,3
0 09E2 09E3 wc,3
0 0A01 0A02 wc,3
0 0A3C 0A3C wc,3
0 0A41 0A42 wc,3
0 0A47 0A48 wc,3
0 0A4B 0A4D wc,3
0 0A70 0A71 wc,3
0 0A81 0A82 wc,3
0 0ABC 0ABC wc,3
0 0AC1 0AC5 wc,3
0 0AC7 0AC8 wc,3
0 0ACD 0ACD wc,3
0 0AE2 0AE3 wc,3
0 0B01 0B01 wc,3
0 0B3C 0B3C wc,3
0 0B3F 0B3F wc,3
0 0B41 0B43 wc,3
0 0B4D 0B4D wc,3
0 0B56 0B56 wc,3
0 0B82 0B82 wc,3
0 0BC0 0BC0 wc,3
0 0BCD 0BCD wc,3
0 0C3E 0C40 wc,3
0 0C46 0C48 wc,3
0 0C4A 0C4D wc,3
0 0C55 0C56 wc,3
0 0CBC 0CBC wc,3
0 0CBF 0CBF wc,3
0 0CC6 0CC6 wc,3
0 0CCC 0CCD wc,3
0 0D41 0D43 wc,3
0 0D4D 0D4D wc,3
0 0DCA 0DCA wc,3
0 0DD2 0DD4 wc,3
0 0DD6 0DD6 wc,3
0 0E31 0E31 wc,3
0 0E34 0E3A wc,3
0 0E47 0E4E wc,3
0 0EB1 0EB1 wc,3
0 0EB4 0EB9 wc,3
0 0EBB 0EBC wc,3
0 0EC8 0ECD wc,3
0 0F18 0F19 wc,3
0 0F35 0F35 wc,3
0 0F37 0F37 wc,3
0 0F39 0F39 wc,3
0 0F71 0F7E wc,3
0 0F80 0F84 wc,3
0 0F86 0F87 wc,3
0 0F90 0F97 wc,3
0 0F99 0FBC wc,3
0 0FC6 0FC6 wc,3
0 102D 1030 wc,3
0 1032 1032 wc,3
0 1036 1037 wc,3
0 1039 1039 wc,3
0 1058 1059 wc,3
1 0000 1100 wc,3
2 1100 115f wc,3
0 1160 11FF wc,3
0 1712 1714 wc,3
0 1732 1734 wc,3
0 1752 1753 wc,3
0 1772 1773 wc,3
0 17B4 17B5 wc,3
0 17B7 17BD wc,3
0 17C6 17C6 wc,3
0 17C9 17D3 wc,3
0 17DD 17DD wc,3
0 180B 180D wc,3
0 18A9 18A9 wc,3
0 1920 1922 wc,3
0 1927 1928 wc,3
0 1932 1932 wc,3
0 1939 193B wc,3
0 200B 200F wc,3
0 202A 202E wc,3
0 2060 2063 wc,3
0 206A 206F wc,3
0 20D0 20EA wc,3
2 2329 232A wc,3
0 302A 302F wc,3
2 2E80 303E wc,3
0 3099 309A wc,3
2 3040 A4CF wc,3
2 AC00 D7A3 wc,3
2 F900 FAFF wc,3
0 FB1E FB1E wc,3
0 FE00 FE0F wc,3
0 FE20 FE23 wc,3
2 FE30 FE6F wc,3
0 FEFF FEFF wc,3
2 FF00 FF60 wc,3
2 FFE0 FFE6 wc,3
0 FFF9 FFFB wc,3
0 1D167 1D169 wc,3
0 1D173 1D182 wc,3
0 1D185 1D18B wc,3
0 1D1AA 1D1AD wc,3
2 20000 2FFFD wc,3
2 30000 3FFFD wc,3
0 E0001 E0001 wc,3
0 E0020 E007F wc,3
0 E0100 E01EF wc,3
here wc-table - Constant #wc-table

\ inefficient table walk:

: wcwidth ( xc -- n )
    wc-table #wc-table over + swap ?DO
	dup I 2@ within IF  I 2 cells + @  UNLOOP EXIT  THEN
    3 cells +LOOP  1 ;
[THEN]
    
: u8width ( xcaddr u -- n )
    0 rot rot over + swap ?DO
        I xc@+ swap >r wcwidth +
    r> I - +LOOP ;

: set-encoding-utf-8 ( -- )
    ['] u8emit is xemit
    ['] u8key is xkey
    ['] u8>> is xchar+
    ['] u8<< is xchar-
[ [IFDEF] xstring+ ]
    ['] u8string+ is xstring+
    ['] u8string- is xstring-
    ['] +u8string is +xstring
    ['] -u8string is -xstring
[ [THEN] ]
    ['] u8@ is xc@
    ['] u8!+? is xc!+?
    ['] u8@+ is xc@+
    ['] u8len is xc-size
[ [IFDEF] x-width ]
    ['] u8width is x-width
[ [THEN] ]
    ['] -u8trailing-garbage is -trailing-garbage
;

: utf-8-cold ( -- )
    s" LC_ALL" getenv 2dup d0= IF  2drop
	s" LC_CTYPE" getenv 2dup d0= IF  2drop
	    s" LANG" getenv 2dup d0= IF  2drop
		s" C"  THEN THEN THEN
    s" UTF-8" search nip nip
    IF  set-encoding-utf-8  ELSE  set-encoding-fixed-width  THEN ;

:noname ( -- )
    defers 'cold
    utf-8-cold
; is 'cold

utf-8-cold