Created
March 1, 2014 20:30
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How can I change this impl to work on &[u8] instead of ~[u8]
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| trait Bitbuf { | |
| fn read_bytes(&self, start: uint, len: uint) -> u64; | |
| fn write_bytes(&mut self, start: uint, len: uint, data: u64); | |
| } | |
| // An implementation on a bare buffer | |
| //impl<'a> Bitbuf for &'a [u8] { | |
| impl Bitbuf for ~[u8] { | |
| fn read_bytes(&self, start: uint, len: uint) -> u64 { | |
| let mut data = 0; | |
| for i in range(0, len) { | |
| data |= ( self[start+i] as u64 ) << ( 8 * i ); | |
| } | |
| data | |
| } | |
| fn write_bytes(&mut self, start: uint, len: uint, data: u64) { | |
| for i in range(0, len) { | |
| self[start+i] = ( data >> ( 8 * i ) ) as u8; | |
| } | |
| } | |
| } | |
| #[test] | |
| fn test_read_bytes() { | |
| let bytes: ~[u8] = ~[0,1,2,3,4,5,6,7,8,9,0xA,0xB,0xC,0xD,0xE,0xF]; | |
| for i in range(0u,0xE) { | |
| assert_eq!(bytes.read_bytes(i, 2), ((i as u64) | ((i+1 << 8) as u64))); | |
| } | |
| assert_eq!(bytes.read_bytes(0, 8), 0x0706050403020100u64); | |
| assert_eq!(bytes.read_bytes(8, 8), 0x0F0E0D0C0B0A0908u64); | |
| } | |
| #[test] | |
| fn test_write_bytes() { | |
| let mut bytes: ~[u8] = ~[0, ..8]; | |
| bytes.write_bytes(0, 8, 0x0706050403020100u64); | |
| assert_eq!(bytes, ~[0,1,2,3,4,5,6,7]); | |
| let mut bytes: ~[u8] = ~[0, ..16]; | |
| bytes.write_bytes(8,8,0x0F0E0D0C0B0A0908u64); | |
| assert_eq!(bytes, ~[0,0, 0, 0, 0, 0, 0, 0, | |
| 8,9,0xA,0xB,0xC,0xD,0xE,0xF]); | |
| } |
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trait Bitbuf {
fn read_bytes(&self, start: uint, len: uint) -> u64;
fn write_bytes(&mut self, start: uint, len: uint, data: u64);
}
// An implementation on a bare buffer
impl<'a> Bitbuf for &'a mut [u8] {
fn read_bytes(&self, start: uint, len: uint) -> u64 {
let mut data = 0;
for i in range(0, len) {
data |= ( self[start+i] as u64 ) << ( 8 * i );
}
data
}
fn write_bytes(&mut self, start: uint, len: uint, data: u64) {
for i in range(0, len) {
self[start+i] = ( data >> ( 8 * i ) ) as u8;
}
}
}
impl<'a> Bitbuf for &'a [u8] {
fn read_bytes(&self, start: uint, len: uint) -> u64 {
let mut data = 0;
for i in range(0, len) {
data |= ( self[start+i] as u64 ) << ( 8 * i );
}
data
}
fn write_bytes(&mut self, _: uint, _: uint, _: u64) {
fail!("Can't write immutable buffer");
}
}
[test]
fn test_read_bytes() {
let bytes: ~[u8] = ~[0,1,2,3,4,5,6,7,8,9,0xA,0xB,0xC,0xD,0xE,0xF];
for i in range(0u,0xE) {
assert_eq!(bytes.read_bytes(i, 2), ((i as u64) | ((i+1 << 8) as u64)));
}
assert_eq!(bytes.read_bytes(0, 8), 0x0706050403020100u64);
assert_eq!(bytes.read_bytes(8, 8), 0x0F0E0D0C0B0A0908u64);
}
[test]
fn test_write_bytes() {
let mut bytes: ~[u8] = ~[0, ..8];
bytes.as_mut_slice().write_bytes(0, 8, 0x0706050403020100u64);
assert_eq!(bytes, ~[0,1,2,3,4,5,6,7]);
let mut bytes: ~[u8] = ~[0, ..16];
bytes.as_mut_slice().write_bytes(8,8,0x0F0E0D0C0B0A0908u64);
assert_eq!(bytes, ~[0,0, 0, 0, 0, 0, 0, 0,
8,9,0xA,0xB,0xC,0xD,0xE,0xF]);
}