Annotation of gforth/utf-8.fs, revision 1.22

1.1       pazsan      1: \ UTF-8 handling                                       12dec04py
                      2: 
1.18      anton       3: \ Copyright (C) 2004,2005 Free Software Foundation, Inc.
1.1       pazsan      4: 
                      5: \ This file is part of Gforth.
                      6: 
                      7: \ Gforth is free software; you can redistribute it and/or
                      8: \ modify it under the terms of the GNU General Public License
                      9: \ as published by the Free Software Foundation; either version 2
                     10: \ of the License, or (at your option) any later version.
                     11: 
                     12: \ This program is distributed in the hope that it will be useful,
                     13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
                     14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     15: \ GNU General Public License for more details.
                     16: 
                     17: \ You should have received a copy of the GNU General Public License
                     18: \ along with this program; if not, write to the Free Software
                     19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
                     20: 
                     21: \ short: u8 means utf-8 encoded address
                     22: 
1.7       pazsan     23: s" malformed UTF-8 character" exception Constant UTF-8-err
                     24: 
1.13      anton      25: $80 Value max-single-byte
1.10      pazsan     26: 
1.4       pazsan     27: : u8len ( u8 -- n )
1.13      anton      28:     dup      max-single-byte u< IF  drop 1  EXIT  THEN \ special case ASCII
1.1       pazsan     29:     $800  2 >r
1.17      pazsan     30:     BEGIN  2dup u>=  WHILE  5 lshift r> 1+ >r  dup 0= UNTIL  THEN
1.1       pazsan     31:     2drop r> ;
                     32: 
                     33: : u8@+ ( u8addr -- u8addr' u )
1.13      anton      34:     count  dup max-single-byte u< ?EXIT  \ special case ASCII
1.17      pazsan     35:     dup $C2 u< IF  UTF-8-err throw  THEN  \ malformed character
1.1       pazsan     36:     $7F and  $40 >r
                     37:     BEGIN  dup r@ and  WHILE  r@ xor
                     38:            6 lshift r> 5 lshift >r >r count
1.7       pazsan     39:            dup $C0 and $80 <> IF   UTF-8-err throw  THEN
1.1       pazsan     40:            $3F and r> or
                     41:     REPEAT  rdrop ;
                     42: 
                     43: : u8!+ ( u u8addr -- u8addr' )
1.13      anton      44:     over max-single-byte u< IF  tuck c! 1+  EXIT  THEN \ special case ASCII
1.1       pazsan     45:     >r 0 swap  $3F
                     46:     BEGIN  2dup u>  WHILE
                     47:            2/ >r  dup $3F and $80 or swap 6 rshift r>
                     48:     REPEAT  $7F xor 2* or  r>
                     49:     BEGIN   over $80 u>= WHILE  tuck c! 1+  REPEAT  nip ;
                     50: 
1.8       pazsan     51: \ plug-in so that char and '<char> work for UTF-8
                     52: 
1.9       anton      53: [ifundef] char@ \ !! bootstrapping help
                     54:     Defer char@ ( addr u -- char addr' u' )
                     55:     :noname  over c@ -rot 1 /string ; IS char@
                     56: [then]
                     57: 
1.8       pazsan     58: :noname  ( addr u -- char addr' u' )
1.9       anton      59:     \ !! the if here seems to work around some breakage, but not
                     60:     \ entirely; e.g., try '' with LANG=C.
                     61:     dup 1 u<= IF defers char@ EXIT THEN
1.8       pazsan     62:     over + >r u8@+ swap r> over - ; IS char@
                     63: 
1.1       pazsan     64: \ scan to next/previous character
                     65: 
1.13      anton      66: \ alternative names: u8char+ u8char-
                     67: 
1.12      pazsan     68: : u8>> ( u8addr -- u8addr' )  u8@+ drop ;
1.1       pazsan     69: : u8<< ( u8addr -- u8addr' )
1.13      anton      70:     BEGIN  1- dup c@ $C0 and max-single-byte <>  UNTIL ;
1.1       pazsan     71: 
                     72: \ utf key and emit
                     73: 
                     74: : u8key ( -- u )
1.13      anton      75:     defers key dup max-single-byte u< ?EXIT  \ special case ASCII
1.17      pazsan     76:     dup $C2 u< IF  UTF-8-err throw  THEN  \ malformed character
1.1       pazsan     77:     $7F and  $40 >r
                     78:     BEGIN  dup r@ and  WHILE  r@ xor
                     79:            6 lshift r> 5 lshift >r >r defers key
1.7       pazsan     80:            dup $C0 and $80 <> IF  UTF-8-err throw  THEN
1.1       pazsan     81:            $3F and r> or
                     82:     REPEAT  rdrop ;
                     83: 
                     84: : u8emit ( u -- )
1.13      anton      85:     dup max-single-byte u< IF  defers emit  EXIT  THEN \ special case ASCII
1.1       pazsan     86:     0 swap  $3F
                     87:     BEGIN  2dup u>  WHILE
                     88:            2/ >r  dup $3F and $80 or swap 6 rshift r>
                     89:     REPEAT  $7F xor 2* or
                     90:     BEGIN   dup $80 u>= WHILE  defers emit  REPEAT  drop ;
1.13      anton      91: 
                     92: \ utf-8 stuff for xchars
                     93: 
                     94: : +u8/string ( c-addr1 u1 -- c-addr2 u2 )
                     95:     over dup u8>> swap - /string ;
                     96: 
                     97: : -u8/string ( c-addr1 u1 -- c-addr2 u2 )
                     98:     over dup u8<< swap - /string ;
                     99: 
                    100: : u8@ ( c-addr -- u )
                    101:     u8@+ nip ;
                    102: 
                    103: : u8!+? ( xc xc-addr1 u1 -- xc-addr2 u2 f )
                    104:     >r over u8len r@ over u< if ( xc xc-addr1 len r: u1 )
                    105:        \ not enough space
                    106:        drop nip r> false
                    107:     else
                    108:        >r u8!+ r> r> swap - true
                    109:     then ;
                    110: 
                    111: : u8addrlen ( u8-addr -- u )
                    112:     \ length of UTF-8 char starting at u8-addr (accesses only u8-addr)
                    113:     c@
                    114:     dup $80 u< if drop 1 exit endif
                    115:     dup $c0 u< if UTF-8-err throw endif
                    116:     dup $e0 u< if drop 2 exit endif
                    117:     dup $f0 u< if drop 3 exit endif
                    118:     dup $f8 u< if drop 4 exit endif
                    119:     dup $fc u< if drop 5 exit endif
                    120:     dup $fe u< if drop 6 exit endif
                    121:     UTF-8-err throw ;
                    122: 
                    123: : -u8trailing-garbage ( addr u1 -- addr u2 )
                    124:     2dup + dup u8<< ( addr u1 end1 end2 )
                    125:     2dup dup u8addrlen + = if \ last character ok
                    126:        2drop
                    127:     else
                    128:        nip nip over -
                    129:     then ;
                    130: 
1.22    ! anton     131: [IFUNDEF] wcwidth
        !           132:     : wcwidth abort ;
        !           133: [THEN]
        !           134:     
1.19      pazsan    135: : u8width ( xcaddr u -- n )
                    136:     0 rot rot over + swap ?DO
1.22    ! anton     137:         I xc@+ swap >r wcwidth +
1.19      pazsan    138:     r> I - +LOOP ;
                    139: 
1.13      anton     140: : set-encoding-utf-8 ( -- )
                    141:     ['] u8emit is xemit
                    142:     ['] u8key is xkey
                    143:     ['] u8>> is xchar+
                    144:     ['] u8<< is xchar-
                    145:     ['] +u8/string is +x/string
                    146:     ['] -u8/string is -x/string
                    147:     ['] u8@ is xc@
                    148:     ['] u8!+? is xc!+?
                    149:     ['] u8@+ is xc@+
                    150:     ['] u8len is xc-size
1.20      pazsan    151: [ [IFDEF] x-width ]
1.19      pazsan    152:     ['] u8width is x-width
1.20      pazsan    153: [ [THEN] ]
1.13      anton     154:     ['] -u8trailing-garbage is -trailing-garbage
                    155: ;
1.1       pazsan    156: 
1.15      anton     157: : utf-8-cold ( -- )
1.16      pazsan    158:     s" LC_ALL" getenv 2dup d0= IF  2drop
                    159:        s" LC_CTYPE" getenv 2dup d0= IF  2drop
                    160:            s" LANG" getenv 2dup d0= IF  2drop
                    161:                s" C"  THEN THEN THEN
                    162:     s" UTF-8" search nip nip
1.15      anton     163:     IF  set-encoding-utf-8  ELSE  set-encoding-fixed-width  THEN ;
                    164: 
                    165: ' utf-8-cold INIT8 chained
                    166: 
                    167: utf-8-cold

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