ref: 85e637db4543ca443a88bd7d0a1f1efe50a2aecb
dir: /str.myr/
use "die.use"
use "sys.use"
use "types.use"
pkg std =
const Badchar : char = -1 castto(char)
const nextc : (str : byte[,] -> [char, byte[,]])
;;
const nextc = {str
var len : size
var mask
var chr
var i
var c
var tmp
c = str[0]
if c & 0x80 == 0 /* ascii range */
len = 1
elif c & 0xe0 == 0xc0 /* 0b110x_xxxx */
len = 2
elif c & 0xf0 == 0xe0 /* 0b1110_xxxx */
len = 3
elif c & 0xf8 == 0xf0 /* 0b1111_0xxx */
len = 4
else
/* skip one char forward so we can try
resyncing the character stream */
-> (Badchar, str[1,str.len])
;;
mask = ((1 << (8 - len)) - 1) ^ 0xff
chr = c castto(uint32)
for i = 1; i < len; i++
tmp = str[i]
chr = chr << 8 | tmp castto(uint32)
;;
-> (chr castto(char), str[len, str.len])
}