On 2014-03-23 21:22:58 +0000, Andrei Alexandrescu
<[email protected]> said:
Here's a baseline: http://goo.gl/91vIGc. Destroy!
Optimizing for smallest assembly size:
dchar front(char[] s)
{
size_t bytesize;
dchar result;
switch (s[0])
{
case 0b00000000: .. case 0b01111111:
return s[0];
case 0b11000000: .. case 0b11011111:
return ((s[0] & 0b00011111) << 6) | (s[1] & 0b00011111);
case 0b11100000: .. case 0b11101111:
result = s[0] & 0b00001111;
bytesize = 3;
break;
case 0b11110000: .. case 0b11110111:
result = s[0] & 0b00000111;
bytesize = 4;
default:
return dchar.init;
}
foreach (i; 1..bytesize)
result = (result << 6) | (s[i] & 0b00111111);
return result;
}
--
Michel Fortin
[email protected]
http://michelf.ca
