Further decoder reworks + add qoi_decode_to_buf()
This commit is contained in:
Ivan Smirnov
parent
343f11bccf
commit
acdd29060c
138
src/decode.rs
138
src/decode.rs
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@ -15,81 +15,104 @@ const QOI_OP_RUN_END: u8 = QOI_OP_RUN | 0x3d; // <- note, 0x3d (not 0x3f)
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const QOI_OP_DIFF_END: u8 = QOI_OP_DIFF | 0x3f;
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const QOI_OP_LUMA_END: u8 = QOI_OP_LUMA | 0x3f;
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pub fn qoi_decode_impl<const N: usize, const RGBA: bool>(
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data: &[u8], n_pixels: usize,
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) -> Result<Vec<u8>>
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#[inline(always)]
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pub const fn hash_pixel<const N: usize>(px: [u8; N]) -> u8 {
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let r = px[0].wrapping_mul(3);
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let g = px[1].wrapping_mul(5);
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let b = px[2].wrapping_mul(7);
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let a = (if N == 4 { px[3] } else { 0xff }).wrapping_mul(11);
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r.wrapping_add(g).wrapping_add(b).wrapping_add(a) & 0x3f
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}
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macro_rules! decode {
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(rgb: $r:expr, $g:expr, $b:expr => $px:expr) => {
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$px[0] = $r;
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$px[1] = $g;
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$px[2] = $b;
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};
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(diff: $b1:expr => $px:expr) => {
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$px[0] = $px[0].wrapping_add(($b1 >> 4) & 0x03).wrapping_sub(2);
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$px[1] = $px[1].wrapping_add(($b1 >> 2) & 0x03).wrapping_sub(2);
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$px[2] = $px[2].wrapping_add($b1 & 0x03).wrapping_sub(2);
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};
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(luma: $b1:expr, $b2:expr => $px:expr) => {
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let vg = ($b1 & 0x3f).wrapping_sub(32);
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let vg_8 = vg.wrapping_sub(8);
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let vr = vg_8.wrapping_add(($b2 >> 4) & 0x0f);
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let vb = vg_8.wrapping_add($b2 & 0x0f);
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$px[0] = $px[0].wrapping_add(vr);
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$px[1] = $px[1].wrapping_add(vg);
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$px[2] = $px[2].wrapping_add(vb);
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};
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}
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#[inline]
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fn qoi_decode_impl_slice<const N: usize, const RGBA: bool>(
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data: &[u8], out: &mut [u8],
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) -> Result<()>
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where
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Pixel<N>: SupportedChannels,
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[u8; N]: Pod,
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{
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if unlikely(data.len() < QOI_HEADER_SIZE + QOI_PADDING_SIZE) {
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return Err(Error::InputBufferTooSmall {
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size: data.len(),
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required: QOI_HEADER_SIZE + QOI_PADDING_SIZE,
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});
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let mut pixels = cast_slice_mut::<_, [u8; N]>(out);
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let mut data = data;
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let mut index = [[0_u8; N]; 256];
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let mut px = [0_u8; N];
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if N == 4 {
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px[3] = 0xff;
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}
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let mut out = vec![0; n_pixels * N]; // unnecessary zero-init, but w/e
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let mut pixels = cast_slice_mut::<_, [u8; N]>(&mut out);
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let mut data = &data[QOI_HEADER_SIZE..];
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let mut index = [Pixel::<N>::new(); 256];
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let mut px = Pixel::<N>::new().with_a(0xff);
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while let [px_out, ptail @ ..] = pixels {
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pixels = ptail;
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match data {
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[b1 @ QOI_OP_INDEX..=QOI_OP_INDEX_END, dtail @ ..] => {
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px = index[usize::from(*b1)];
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*px_out = px.into();
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px = index[*b1 as usize];
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*px_out = px;
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data = dtail;
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continue;
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}
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[QOI_OP_RGB, r, g, b, dtail @ ..] => {
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px = Pixel::from_rgb(Pixel::from_array([*r, *g, *b]), px.a_or(0xff));
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decode!(rgb: *r, *g, *b => px);
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data = dtail;
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}
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[QOI_OP_RGBA, r, g, b, a, dtail @ ..] if RGBA => {
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px = Pixel::from_array([*r, *g, *b, *a]);
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decode!(rgb: *r, *g, *b => px);
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if N == 4 {
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px[3] = *a;
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}
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data = dtail;
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}
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[b1 @ QOI_OP_RUN..=QOI_OP_RUN_END, dtail @ ..] => {
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*px_out = px.into();
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let run = usize::from(b1 & 0x3f).min(pixels.len());
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*px_out = px;
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let run = ((b1 & 0x3f) as usize).min(pixels.len());
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let (phead, ptail) = pixels.split_at_mut(run); // can't panic
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phead.fill(px.into());
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phead.fill(px);
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pixels = ptail;
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data = dtail;
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continue;
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}
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[b1 @ QOI_OP_DIFF..=QOI_OP_DIFF_END, dtail @ ..] => {
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px.rgb_add(
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((b1 >> 4) & 0x03).wrapping_sub(2),
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((b1 >> 2) & 0x03).wrapping_sub(2),
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(b1 & 0x03).wrapping_sub(2),
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);
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decode!(diff: b1 => px);
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data = dtail;
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}
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[b1 @ QOI_OP_LUMA..=QOI_OP_LUMA_END, b2, dtail @ ..] => {
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let vg = (b1 & 0x3f).wrapping_sub(32);
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let vg_8 = vg.wrapping_sub(8);
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let vr = vg_8.wrapping_add((b2 >> 4) & 0x0f);
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let vb = vg_8.wrapping_add(b2 & 0x0f);
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px.rgb_add(vr, vg, vb);
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decode!(luma: b1, b2 => px);
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data = dtail;
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}
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_ => {
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cold();
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if unlikely(data.len() < 8) {
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return Err(Error::UnexpectedBufferEnd);
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if unlikely(data.len() < QOI_PADDING_SIZE) {
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return Err(Error::UnexpectedBufferEnd); // TODO: remove InputDataSize err
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}
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}
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}
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index[usize::from(px.hash_index())] = px;
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*px_out = px.into();
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index[hash_pixel(px) as usize] = px;
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*px_out = px;
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}
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Ok(out)
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Ok(())
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}
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pub trait MaybeChannels {
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@ -110,6 +133,37 @@ impl MaybeChannels for Option<u8> {
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}
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}
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#[inline]
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fn qoi_decode_impl_slice_all(
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data: &[u8], out: &mut [u8], channels: u8, src_channels: u8,
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) -> Result<()> {
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match (channels, src_channels) {
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(3, 3) => qoi_decode_impl_slice::<3, false>(data, out),
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(3, 4) => qoi_decode_impl_slice::<3, true>(data, out),
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(4, 3) => qoi_decode_impl_slice::<4, false>(data, out),
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(4, 4) => qoi_decode_impl_slice::<4, true>(data, out),
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_ => {
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cold();
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return Err(Error::InvalidChannels { channels });
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}
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}
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}
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#[inline]
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pub fn qoi_decode_to_buf(
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mut out: impl AsMut<[u8]>, data: impl AsRef<[u8]>, channels: impl MaybeChannels,
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) -> Result<Header> {
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let (out, data) = (out.as_mut(), data.as_ref());
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let header = Header::decode(data)?;
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let channels = channels.maybe_channels().unwrap_or(header.channels);
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let size = header.n_pixels() * channels as usize;
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if unlikely(out.len() < size) {
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return Err(Error::OutputBufferTooSmall { size: out.len(), required: size });
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}
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let data = &data[QOI_HEADER_SIZE..]; // can't panic
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qoi_decode_impl_slice_all(data, out, header.channels, channels).map(|_| header)
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}
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#[inline]
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pub fn qoi_decode_to_vec(
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data: impl AsRef<[u8]>, channels: impl MaybeChannels,
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@ -117,13 +171,9 @@ pub fn qoi_decode_to_vec(
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let data = data.as_ref();
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let header = Header::decode(data)?;
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let channels = channels.maybe_channels().unwrap_or(header.channels);
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match (channels, header.channels) {
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(3, 3) => Ok((header, qoi_decode_impl::<3, false>(data, header.n_pixels())?)),
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(3, 4) => Ok((header, qoi_decode_impl::<3, true>(data, header.n_pixels())?)),
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(4, 3) => Ok((header, qoi_decode_impl::<4, false>(data, header.n_pixels())?)),
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(4, 4) => Ok((header, qoi_decode_impl::<4, true>(data, header.n_pixels())?)),
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_ => Err(Error::InvalidChannels { channels }),
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}
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let mut out = vec![0; header.n_pixels() * channels as usize];
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let data = &data[QOI_HEADER_SIZE..]; // can't panic
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qoi_decode_impl_slice_all(data, &mut out, header.channels, channels).map(|_| (header, out))
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}
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#[inline]
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