Files
squoosh/codecs/rotate/rotate.rs

114 lines
3.6 KiB
Rust

use std::slice::{from_raw_parts, from_raw_parts_mut};
// This function is taken from Zachary Dremann
// https://github.com/GoogleChromeLabs/squoosh/pull/462
trait HardUnwrap<T> {
fn unwrap_hard(self) -> T;
}
impl<T> HardUnwrap<T> for Option<T> {
#[cfg(not(debug_assertions))]
#[inline]
fn unwrap_hard(self) -> T {
match self {
Some(t) => t,
None => std::process::abort(),
}
}
#[cfg(debug_assertions)]
fn unwrap_hard(self) -> T {
self.unwrap()
}
}
const TILE_SIZE: usize = 16;
fn get_buffers<'a>(width: usize, height: usize) -> (&'a [u32], &'a mut [u32]) {
let num_pixels = width * height;
let in_b: &[u32];
let out_b: &mut [u32];
unsafe {
in_b = from_raw_parts::<u32>(8 as *const u32, num_pixels);
out_b = from_raw_parts_mut::<u32>((num_pixels * 4 + 8) as *mut u32, num_pixels);
}
return (in_b, out_b);
}
#[inline(never)]
fn rotate_0(width: usize, height: usize) {
let (in_b, out_b) = get_buffers(width, height);
for (in_p, out_p) in in_b.iter().zip(out_b.iter_mut()) {
*out_p = *in_p;
}
}
#[inline(never)]
fn rotate_90(width: usize, height: usize) {
let (in_b, out_b) = get_buffers(width, height);
let new_width = height;
let _new_height = width;
for y_start in (0..height).step_by(TILE_SIZE) {
for x_start in (0..width).step_by(TILE_SIZE) {
for y in y_start..(y_start + TILE_SIZE).min(height) {
let in_offset = y * width;
let in_bounds = if x_start + TILE_SIZE < width {
(in_offset + x_start)..(in_offset + x_start + TILE_SIZE)
} else {
(in_offset + x_start)..(in_offset + width)
};
let in_chunk = in_b.get(in_bounds).unwrap_hard();
for (x, in_p) in in_chunk.iter().enumerate() {
let new_x = (new_width - 1) - y;
let new_y = x + x_start;
*out_b.get_mut(new_y * new_width + new_x).unwrap_hard() = *in_p;
}
}
}
}
}
#[inline(never)]
fn rotate_180(width: usize, height: usize) {
let (in_b, out_b) = get_buffers(width, height);
for (in_p, out_p) in in_b.iter().zip(out_b.iter_mut().rev()) {
*out_p = *in_p;
}
}
#[inline(never)]
fn rotate_270(width: usize, height: usize) {
let (in_b, out_b) = get_buffers(width, height);
let new_width = height;
let new_height = width;
for y_start in (0..height).step_by(TILE_SIZE) {
for x_start in (0..width).step_by(TILE_SIZE) {
for y in y_start..(y_start + TILE_SIZE).min(height) {
let in_offset = y * width;
let in_bounds = if x_start + TILE_SIZE < width {
(in_offset + x_start)..(in_offset + x_start + TILE_SIZE)
} else {
(in_offset + x_start)..(in_offset + width)
};
let in_chunk = in_b.get(in_bounds).unwrap_hard();
for (x, in_p) in in_chunk.iter().enumerate() {
let new_x = y;
let new_y = new_height - 1 - (x_start + x);
*out_b.get_mut(new_y * new_width + new_x).unwrap_hard() = *in_p;
}
}
}
}
}
#[no_mangle]
fn rotate(width: usize, height: usize, rotate: usize) {
match rotate {
0 => rotate_0(width, height),
90 => rotate_90(width, height),
180 => rotate_180(width, height),
270 => rotate_270(width, height),
_ => std::process::abort(),
}
}