Annotation of gforth/kernel/xchars.fs, revision 1.3

1.1       anton       1: \ extended characters (either 8bit or UTF-8, possibly other encodings)
                      2: \ and their fixed-size variant
                      3: 
                      4: \ Copyright (C) 2005 Free Software Foundation, Inc.
                      5: 
                      6: \ This file is part of Gforth.
                      7: 
                      8: \ Gforth is free software; you can redistribute it and/or
                      9: \ modify it under the terms of the GNU General Public License
                     10: \ as published by the Free Software Foundation; either version 2
                     11: \ of the License, or (at your option) any later version.
                     12: 
                     13: \ This program is distributed in the hope that it will be useful,
                     14: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
                     15: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     16: \ GNU General Public License for more details.
                     17: 
                     18: \ You should have received a copy of the GNU General Public License
                     19: \ along with this program; if not, write to the Free Software
                     20: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
                     21: 
                     22: \ We can do some of these (and possibly faster) by just using the
                     23: \ utf-8 words with an appropriate setting of max-single-byte, but I
                     24: \ like to see how an 8bit setting without UTF-8 stuff looks like.
                     25: 
                     26: DEFER XEMIT ( xc -- )
                     27: DEFER XKEY ( -- xc )
                     28: DEFER XCHAR+ ( xc-addr1 -- xc-addr2 )
                     29: DEFER XCHAR- ( xc-addr1 -- xc-addr2 )
                     30: DEFER +X/STRING ( xc-addr1 u1 -- xc-addr2 u2 )
                     31: DEFER -X/STRING ( xc-addr1 u1 -- xc-addr2 u2 )
                     32: DEFER XC@ ( xc-addr -- xc )
                     33: DEFER XC!+? ( xc xc-addr1 u1 -- xc-addr2 u2 f ) \ f if operation succeeded
                     34: DEFER XC@+ ( xc-addr1 -- xc-addr2 xc )
                     35: DEFER XC-SIZE ( xc -- u ) \ size in cs
                     36: DEFER -TRAILING-GARBAGE ( addr u1 -- addr u2 ) \ remove trailing incomplete xc
                     37: 
1.2       anton      38: \ derived words, faster implementations are probably possible
                     39: 
                     40: : X@+/string ( xc-addr1 u1 -- xc-addr2 u2 xc )
                     41:     \ !! check for errors?
                     42:     over >r +x/string
                     43:     r> xc@ ;
                     44: 
1.1       anton      45: \ fixed-size versions of these words
                     46: 
                     47: : char- ( c-addr1 -- c-addr2 )
                     48:     [ 1 chars ] literal - ;
                     49: 
                     50: : 1/string ( c-addr1 u1 -- c-addr2 u2 )
                     51:     1 /string ;
                     52: 
                     53: : -1/string ( c-addr1 u1 -- c-addr2 u2 )
                     54:     -1 /string ;
                     55: 
                     56: : c!+? ( c c-addr1 u1 -- c-addr2 u2 f )
1.3     ! anton      57:     dup 1 chars u< if \ or use < ?
        !            58:        rot drop false
        !            59:     else
1.1       anton      60:        >r dup >r c!
1.3     ! anton      61:        r> r> 1 /string true
1.1       anton      62:     then ;
                     63: 
                     64: : c-size ( c -- 1 )
                     65:     drop 1 ;
                     66: 
                     67: : set-encoding-fixed-width ( -- )
                     68:     ['] emit is xemit
                     69:     ['] key is xkey
                     70:     ['] char+ is xchar+
                     71:     ['] char- is xchar-
                     72:     ['] 1/string is +x/string
                     73:     ['] -1/string is -x/string
                     74:     ['] c@ is xc@
                     75:     ['] c!+? is xc!+?
                     76:     ['] count is xc@+
                     77:     ['] c-size is xc-size
                     78:     ['] noop is -trailing-garbage
                     79: ;

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