use crate::imp_crc;
imp_crc!(u16);
#[inline]
fn update_slice_by_4<'a>(
mut crc: u16, mut bytes: &'a [u8], lut: &[[u16; 256]], reflect: bool,
) -> (u16, &'a [u8]) {
const STEP: usize = 4;
assert!(lut.len() >= STEP);
if reflect {
while bytes.len() >= STEP {
crc = lut[0x0][bytes[0x3] as usize]
^ lut[0x1][bytes[0x2] as usize]
^ lut[0x2][bytes[0x1] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0x3][bytes[0x0] as usize ^ (crc & 0xFF) as usize];
bytes = &bytes[STEP..];
}
} else {
while bytes.len() >= STEP {
crc = lut[0x3][bytes[0x0] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0x2][bytes[0x1] as usize ^ (crc & 0xFF) as usize]
^ lut[0x1][bytes[0x2] as usize]
^ lut[0x0][bytes[0x3] as usize];
bytes = &bytes[STEP..];
}
}
(crc, bytes)
}
#[inline]
fn update_slice_by_8<'a>(
mut crc: u16, mut bytes: &'a [u8], lut: &[[u16; 256]], reflect: bool,
) -> (u16, &'a [u8]) {
const STEP: usize = 8;
assert!(lut.len() >= STEP);
if reflect {
while bytes.len() >= STEP {
crc = lut[0x0][bytes[0x7] as usize]
^ lut[0x1][bytes[0x6] as usize]
^ lut[0x2][bytes[0x5] as usize]
^ lut[0x3][bytes[0x4] as usize]
^ lut[0x4][bytes[0x3] as usize]
^ lut[0x5][bytes[0x2] as usize]
^ lut[0x6][bytes[0x1] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0x7][bytes[0x0] as usize ^ (crc & 0xFF) as usize];
bytes = &bytes[STEP..];
}
} else {
while bytes.len() >= STEP {
crc = lut[0x7][bytes[0x0] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0x6][bytes[0x1] as usize ^ (crc & 0xFF) as usize]
^ lut[0x5][bytes[0x2] as usize]
^ lut[0x4][bytes[0x3] as usize]
^ lut[0x3][bytes[0x4] as usize]
^ lut[0x2][bytes[0x5] as usize]
^ lut[0x1][bytes[0x6] as usize]
^ lut[0x0][bytes[0x7] as usize];
bytes = &bytes[STEP..];
}
}
(crc, bytes)
}
#[inline]
fn update_slice_by_16<'a>(
mut crc: u16, mut bytes: &'a [u8], lut: &[[u16; 256]], reflect: bool,
) -> (u16, &'a [u8]) {
const STEP: usize = 16;
assert!(lut.len() >= STEP);
if reflect {
while bytes.len() >= STEP {
crc = lut[0x0][bytes[0xf] as usize]
^ lut[0x1][bytes[0xe] as usize]
^ lut[0x2][bytes[0xd] as usize]
^ lut[0x3][bytes[0xc] as usize]
^ lut[0x4][bytes[0xb] as usize]
^ lut[0x5][bytes[0xa] as usize]
^ lut[0x6][bytes[0x9] as usize]
^ lut[0x7][bytes[0x8] as usize]
^ lut[0x8][bytes[0x7] as usize]
^ lut[0x9][bytes[0x6] as usize]
^ lut[0xa][bytes[0x5] as usize]
^ lut[0xb][bytes[0x4] as usize]
^ lut[0xc][bytes[0x3] as usize]
^ lut[0xd][bytes[0x2] as usize]
^ lut[0xe][bytes[0x1] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0xf][bytes[0x0] as usize ^ (crc & 0xFF) as usize];
bytes = &bytes[STEP..];
}
} else {
while bytes.len() >= STEP {
crc = lut[0xf][bytes[0x0] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0xe][bytes[0x1] as usize ^ (crc & 0xFF) as usize]
^ lut[0xd][bytes[0x2] as usize]
^ lut[0xc][bytes[0x3] as usize]
^ lut[0xb][bytes[0x4] as usize]
^ lut[0xa][bytes[0x5] as usize]
^ lut[0x9][bytes[0x6] as usize]
^ lut[0x8][bytes[0x7] as usize]
^ lut[0x7][bytes[0x8] as usize]
^ lut[0x6][bytes[0x9] as usize]
^ lut[0x5][bytes[0xa] as usize]
^ lut[0x4][bytes[0xb] as usize]
^ lut[0x3][bytes[0xc] as usize]
^ lut[0x2][bytes[0xd] as usize]
^ lut[0x1][bytes[0xe] as usize]
^ lut[0x0][bytes[0xf] as usize];
bytes = &bytes[STEP..];
}
}
(crc, bytes)
}
#[inline]
fn update_slice_by_32<'a>(
mut crc: u16, mut bytes: &'a [u8], lut: &[[u16; 256]], reflect: bool,
) -> (u16, &'a [u8]) {
const STEP: usize = 32;
assert!(lut.len() >= STEP);
if reflect {
while bytes.len() >= STEP {
crc = lut[0x00][bytes[0x1f] as usize]
^ lut[0x01][bytes[0x1e] as usize]
^ lut[0x02][bytes[0x1d] as usize]
^ lut[0x03][bytes[0x1c] as usize]
^ lut[0x04][bytes[0x1b] as usize]
^ lut[0x05][bytes[0x1a] as usize]
^ lut[0x06][bytes[0x19] as usize]
^ lut[0x07][bytes[0x18] as usize]
^ lut[0x08][bytes[0x17] as usize]
^ lut[0x09][bytes[0x16] as usize]
^ lut[0x0a][bytes[0x15] as usize]
^ lut[0x0b][bytes[0x14] as usize]
^ lut[0x0c][bytes[0x13] as usize]
^ lut[0x0d][bytes[0x12] as usize]
^ lut[0x0e][bytes[0x11] as usize]
^ lut[0x0f][bytes[0x10] as usize]
^ lut[0x10][bytes[0x0f] as usize]
^ lut[0x11][bytes[0x0e] as usize]
^ lut[0x12][bytes[0x0d] as usize]
^ lut[0x13][bytes[0x0c] as usize]
^ lut[0x14][bytes[0x0b] as usize]
^ lut[0x15][bytes[0x0a] as usize]
^ lut[0x16][bytes[0x09] as usize]
^ lut[0x17][bytes[0x08] as usize]
^ lut[0x18][bytes[0x07] as usize]
^ lut[0x19][bytes[0x06] as usize]
^ lut[0x1a][bytes[0x05] as usize]
^ lut[0x1b][bytes[0x04] as usize]
^ lut[0x1c][bytes[0x03] as usize]
^ lut[0x1d][bytes[0x02] as usize]
^ lut[0x1e][bytes[0x01] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0x1f][bytes[0x00] as usize ^ (crc & 0xFF) as usize];
bytes = &bytes[STEP..];
}
} else {
while bytes.len() >= STEP {
crc = lut[0x1f][bytes[0x00] as usize ^ ((crc >> 0x08) & 0xFF) as usize]
^ lut[0x1e][bytes[0x01] as usize ^ (crc & 0xFF) as usize]
^ lut[0x1d][bytes[0x02] as usize]
^ lut[0x1c][bytes[0x03] as usize]
^ lut[0x1b][bytes[0x04] as usize]
^ lut[0x1a][bytes[0x05] as usize]
^ lut[0x19][bytes[0x06] as usize]
^ lut[0x18][bytes[0x07] as usize]
^ lut[0x17][bytes[0x08] as usize]
^ lut[0x16][bytes[0x09] as usize]
^ lut[0x15][bytes[0x0a] as usize]
^ lut[0x14][bytes[0x0b] as usize]
^ lut[0x13][bytes[0x0c] as usize]
^ lut[0x12][bytes[0x0d] as usize]
^ lut[0x11][bytes[0x0e] as usize]
^ lut[0x10][bytes[0x0f] as usize]
^ lut[0x0f][bytes[0x10] as usize]
^ lut[0x0e][bytes[0x11] as usize]
^ lut[0x0d][bytes[0x12] as usize]
^ lut[0x0c][bytes[0x13] as usize]
^ lut[0x0b][bytes[0x14] as usize]
^ lut[0x0a][bytes[0x15] as usize]
^ lut[0x09][bytes[0x16] as usize]
^ lut[0x08][bytes[0x17] as usize]
^ lut[0x07][bytes[0x18] as usize]
^ lut[0x06][bytes[0x19] as usize]
^ lut[0x05][bytes[0x1a] as usize]
^ lut[0x04][bytes[0x1b] as usize]
^ lut[0x03][bytes[0x1c] as usize]
^ lut[0x02][bytes[0x1d] as usize]
^ lut[0x01][bytes[0x1e] as usize]
^ lut[0x00][bytes[0x1f] as usize];
bytes = &bytes[STEP..];
}
}
(crc, bytes)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::internals::MAX_SLICES;
const SLICES: usize = MAX_SLICES;
#[test]
fn with_reflect() {
const POLY: u16 = 0x1021;
const INIT: u16 = 0x0000;
const REFLECT: bool = true;
const XOR_OUT: u16 = 0x0000;
const WIDTH: u8 = 16;
const SAMPLES: [(&str, u16); 8] = [
("", 0x0000),
("0", 0x3183),
("012", 0x3B45),
("0123456", 0xC7B7),
("123456789", 0x2189),
("0123456789ABCDE", 0x9FFE),
("0123456789ABCDEFGHIJKLMNOPQRSTU", 0x19D4),
("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", 0xDC1A),
];
let lut32 = make_lut_32(WIDTH, POLY, REFLECT);
let lut256 = make_lut_256(WIDTH, POLY, REFLECT);
let lut256x_n = make_lut_256x_n::<SLICES>(WIDTH, POLY, REFLECT);
for sample in SAMPLES {
assert_eq!(
update_no_lut(INIT, WIDTH, POLY, REFLECT, sample.0.as_bytes()) ^ XOR_OUT,
sample.1
);
assert_eq!(
update_lut_32(INIT, sample.0.as_bytes(), &lut32, REFLECT) ^ XOR_OUT,
sample.1
);
assert_eq!(
update_lut_256(INIT, sample.0.as_bytes(), &lut256, REFLECT) ^ XOR_OUT,
sample.1
);
assert_eq!(
update_lut_256x_n::<SLICES>(INIT, sample.0.as_bytes(), &lut256x_n, REFLECT)
^ XOR_OUT,
sample.1
);
}
}
#[test]
fn without_reflect() {
const POLY: u16 = 0xC867;
const INIT: u16 = 0xFFFF;
const REFLECT: bool = false;
const XOR_OUT: u16 = 0x0000;
const WIDTH: u8 = 16;
const SAMPLES: [(&str, u16); 8] = [
("", 0xFFFF),
("0", 0x0528),
("012", 0x1E42),
("0123456", 0x998F),
("123456789", 0x4C06),
("0123456789ABCDE", 0x86F3),
("0123456789ABCDEFGHIJKLMNOPQRSTU", 0xCDB1),
("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", 0x53EC),
];
let lut32 = make_lut_32(WIDTH, POLY, REFLECT);
let lut256 = make_lut_256(WIDTH, POLY, REFLECT);
let lut256x_n = make_lut_256x_n::<SLICES>(WIDTH, POLY, REFLECT);
for sample in SAMPLES {
assert_eq!(
update_no_lut(INIT, WIDTH, POLY, REFLECT, sample.0.as_bytes()) ^ XOR_OUT,
sample.1
);
assert_eq!(
update_lut_32(INIT, sample.0.as_bytes(), &lut32, REFLECT) ^ XOR_OUT,
sample.1
);
assert_eq!(
update_lut_256(INIT, sample.0.as_bytes(), &lut256, REFLECT) ^ XOR_OUT,
sample.1
);
assert_eq!(
update_lut_256x_n::<SLICES>(INIT, sample.0.as_bytes(), &lut256x_n, REFLECT)
^ XOR_OUT,
sample.1
);
}
}
}