isleadb.gml

来自「开放源码的编译器open watcom 1.6.0版的源代码」· GML 代码 · 共 79 行

.func isleadbyte
#include <ctype.h>
int isleadbyte( int ch );
.ixfunc2 '&CharTest' &func
.funcend
.desc begin
The &func function tests if the argument
.arg ch
is a valid first byte of a multibyte character in the current code
page.
.np
For example, in code page 932, a valid lead byte is any byte in the
range 0x81 through 0x9F or 0xE0 through 0xFC.
.desc end
.return begin
The &func function returns a non-zero value when the argument is a
valid lead byte.
Otherwise, zero is returned.
.return end
.see begin
.im seeis &function.
.see end
.exmp begin
#include <stdio.h>
#include <ctype.h>
#include <mbctype.h>

const unsigned char chars[] = {
    ' ',
    '.',
    '1',
    'A',
    0x81,0x40, /* double-byte space */
    0x82,0x60, /* double-byte A */
    0x82,0xA6, /* double-byte Hiragana */
    0x83,0x42, /* double-byte Katakana */
    0xA1,      /* single-byte Katakana punctuation */
    0xA6,      /* single-byte Katakana alphabetic */
    0xDF,      /* single-byte Katakana alphabetic */
    0xE0,0xA1, /* double-byte Kanji */
    0x00
};
.exmp break
#define SIZE sizeof( chars ) / sizeof( char )
.exmp break
void main()
  {
    int   i;
.exmp break
    _setmbcp( 932 );
    for( i = 0; i < SIZE; i++ ) {
      printf( "%2.2x is %sa valid lead byte\n",
            chars[i],
            ( isleadbyte( chars[i] ) ) ? "" : "not " );
    }
  }
.exmp output
20 is not a valid lead byte
2e is not a valid lead byte
31 is not a valid lead byte
41 is not a valid lead byte
81 is a valid lead byte
40 is not a valid lead byte
82 is a valid lead byte
60 is not a valid lead byte
82 is a valid lead byte
a6 is not a valid lead byte
83 is a valid lead byte
42 is not a valid lead byte
a1 is not a valid lead byte
a6 is not a valid lead byte
df is not a valid lead byte
e0 is a valid lead byte
a1 is not a valid lead byte
00 is not a valid lead byte
.exmp end
.class WATCOM
.system