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lossy compression

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Crispy 2024-04-12 18:47:40 +02:00
parent 242724d7fd
commit 8bfeb6d2f3
4 changed files with 194 additions and 37 deletions
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34
encoder/src/util.rs
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@ -107,13 +107,17 @@ pub fn render_images(left: &Frame, right: &Frame) {
}
pub fn rle_255_encode(raw: &[u8]) -> Vec<u8> {
rle_encode(raw, 255)
}
pub fn rle_encode(raw: &[u8], max: u8) -> Vec<u8> {
let mut encoded = Vec::new();
let mut last_val = 0;
let mut run = 0;
for &val in raw {
if val != last_val || run == 255 {
if val != last_val || run == max {
encoded.push(run);
if run == 255 && val == last_val {
if run == max && val == last_val {
encoded.push(0);
}
run = 1;
@ -126,7 +130,31 @@ pub fn rle_255_encode(raw: &[u8]) -> Vec<u8> {
encoded
}
pub fn rle_255_decode_until(encoded: &[u8], max_size: usize) -> (usize, Vec<u8>) {
pub fn pack_nybbles(mut nybbles: Vec<u8>) -> Vec<u8> {
if nybbles.len() % 2 == 1 {
nybbles.push(0);
}
assert!(nybbles.iter().all(|&n| n < 16));
let mut packed = Vec::with_capacity(nybbles.len() / 2);
for i in 0..(nybbles.len() / 2) {
let upper = nybbles[i * 2] << 4;
let lower = nybbles[i * 2 + 1] & 15;
let byte = upper | lower;
packed.push(byte);
}
packed
}
pub fn unpack_nybbles(packed: &[u8]) -> Vec<u8> {
let mut nybbles = Vec::with_capacity(packed.len() * 2);
for &p in packed {
nybbles.push(p >> 4);
nybbles.push(p & 15);
}
nybbles
}
pub fn rle_255_decode(encoded: &[u8], max_size: usize) -> (usize, Vec<u8>) {
let mut raw = Vec::new();
let mut val = 0;
let mut consumed_bytes = 0;