Joel Galenson | 8249a3d | 2021-06-21 14:01:00 -0700 | [diff] [blame^] | 1 | use core::convert::TryInto; |
| 2 | |
| 3 | pub trait ByteOrder { |
| 4 | fn read_u16(buf: &[u8]) -> u16; |
| 5 | fn read_u32(buf: &[u8]) -> u32; |
| 6 | fn read_u64(buf: &[u8]) -> u64; |
| 7 | fn read_uint(buf: &[u8], nbytes: usize) -> u64; |
| 8 | fn write_u16(buf: &mut [u8], n: u16); |
| 9 | fn write_u32(buf: &mut [u8], n: u32); |
| 10 | fn write_u64(buf: &mut [u8], n: u64); |
| 11 | fn write_uint(buf: &mut [u8], n: u64, nbytes: usize); |
| 12 | } |
| 13 | |
| 14 | pub enum BigEndian {} |
| 15 | pub enum LittleEndian {} |
| 16 | pub enum NativeEndian {} |
| 17 | |
| 18 | macro_rules! impl_endian { |
| 19 | ($t:ty, $from_endian:ident, $to_endian:ident) => { |
| 20 | impl ByteOrder for $t { |
| 21 | #[inline] |
| 22 | fn read_u16(buf: &[u8]) -> u16 { |
| 23 | u16::$from_endian(buf[0..2].try_into().unwrap()) |
| 24 | } |
| 25 | |
| 26 | #[inline] |
| 27 | fn read_u32(buf: &[u8]) -> u32 { |
| 28 | u32::$from_endian(buf[0..4].try_into().unwrap()) |
| 29 | } |
| 30 | |
| 31 | #[inline] |
| 32 | fn read_u64(buf: &[u8]) -> u64 { |
| 33 | u64::$from_endian(buf[0..8].try_into().unwrap()) |
| 34 | } |
| 35 | |
| 36 | #[inline] |
| 37 | fn read_uint(buf: &[u8], nbytes: usize) -> u64 { |
| 38 | let mut dst = [0u8; 8]; |
| 39 | dst[..nbytes].copy_from_slice(&buf[..nbytes]); |
| 40 | u64::$from_endian(dst) |
| 41 | } |
| 42 | |
| 43 | #[inline] |
| 44 | fn write_u16(buf: &mut [u8], n: u16) { |
| 45 | buf[0..2].copy_from_slice(&n.$to_endian()[..]); |
| 46 | } |
| 47 | |
| 48 | #[inline] |
| 49 | fn write_u32(buf: &mut [u8], n: u32) { |
| 50 | buf[0..4].copy_from_slice(&n.$to_endian()[..]); |
| 51 | } |
| 52 | |
| 53 | #[inline] |
| 54 | fn write_u64(buf: &mut [u8], n: u64) { |
| 55 | buf[0..8].copy_from_slice(&n.$to_endian()[..]); |
| 56 | } |
| 57 | |
| 58 | #[inline] |
| 59 | fn write_uint(buf: &mut [u8], n: u64, nbytes: usize) { |
| 60 | buf[..nbytes].copy_from_slice(&n.$to_endian()[..nbytes]); |
| 61 | } |
| 62 | } |
| 63 | }; |
| 64 | } |
| 65 | |
| 66 | impl_endian! { |
| 67 | BigEndian, from_be_bytes, to_be_bytes |
| 68 | } |
| 69 | |
| 70 | impl_endian! { |
| 71 | LittleEndian, from_le_bytes, to_le_bytes |
| 72 | } |
| 73 | |
| 74 | impl_endian! { |
| 75 | NativeEndian, from_ne_bytes, to_ne_bytes |
| 76 | } |