qoi/libqoi/src/lib.rs

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use anyhow::{ensure, Result};
use c_vec::CVec;
use libc::{c_int, c_void};
mod ffi {
use libc::{c_int, c_uchar, c_uint, c_void};
#[derive(Debug, Copy, Clone, Default)]
#[repr(C)]
#[allow(non_camel_case_types)]
pub struct qoi_desc {
pub width: c_uint,
pub height: c_uint,
pub channels: c_uchar,
pub colorspace: c_uchar,
}
extern "C" {
pub fn qoi_encode(
data: *const c_void, desc: *const qoi_desc, out_len: *mut c_int,
) -> *mut c_void;
pub fn qoi_decode(
data: *const c_void, size: c_int, desc: *mut qoi_desc, channels: c_int,
) -> *mut c_void;
}
}
pub use ffi::qoi_desc;
pub fn qoi_encode(data: &[u8], width: u32, height: u32, channels: u8) -> Result<CVec<u8>> {
let desc =
qoi_desc { width: width as _, height: height as _, channels: channels as _, colorspace: 0 };
let mut out_len: c_int = 0;
let out_ptr =
unsafe { ffi::qoi_encode(data.as_ptr().cast(), &desc as *const _, &mut out_len as *mut _) };
ensure!(!out_ptr.is_null(), "qoi.h: qoi_encode() returned null pointer");
ensure!(out_len > 0, "qoi.h: qoi_encode() returned non-positive out_len");
let vec = unsafe {
CVec::new_with_dtor(out_ptr.cast::<u8>(), out_len as _, |p| libc::free(p.cast::<c_void>()))
};
Ok(vec)
}
pub fn qoi_decode(data: &[u8], channels: u8) -> Result<(qoi_desc, CVec<u8>)> {
let mut desc = qoi_desc::default();
let out_ptr = unsafe {
ffi::qoi_decode(data.as_ptr() as _, data.len() as _, &mut desc as *mut _, channels as _)
};
ensure!(!out_ptr.is_null(), "qoi.h: qoi_decode() returned null pointer");
let out_len = (desc.width as usize)
.saturating_mul(desc.height as usize)
.saturating_mul(channels as usize);
let vec = unsafe {
CVec::new_with_dtor(out_ptr.cast::<u8>(), out_len, |p| libc::free(p.cast::<c_void>()))
};
Ok((desc, vec))
}