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gdevcon25/rust/decoder/src/lib.rs

32 lines
994 B
Rust

use std::{mem::transmute, slice};
use zune_jpeg::{zune_core::{colorspace::ColorSpace, options::DecoderOptions}, JpegDecoder};
#[no_mangle]
pub extern "C" fn add(a: u64, b: u64) -> u64 {
a + b
}
#[no_mangle]
/// decode jpeg image of given length
///
/// image format is 0RGB
pub extern "C" fn decode(image: &mut u32, packet: &u8, length: u32) -> u64 {
let packet = unsafe {slice::from_raw_parts(packet, length as usize)};
let image: &mut [u8; 4*320*240] = unsafe{transmute(image)};
let options = DecoderOptions::new_fast().jpeg_set_out_colorspace(ColorSpace::RGB);
let Ok(mut frame) = JpegDecoder::new_with_options(packet, options).decode() else {
return 1; // decoder failure
};
// convert from RGB to 0RGB (and swap endianness)
for (buffer, image) in frame.chunks_exact_mut(3).zip(image.chunks_exact_mut(4)) {
image[0] = buffer[2];
image[1] = buffer[1];
image[2] = buffer[0];
image[3] = 0;
}
0 // success
}