1 files changed, 210 insertions, 0 deletions
diff --git a/vendor/qoi/src/encode.rs b/vendor/qoi/src/encode.rs
new file mode 100644
index 0000000..0ed8476
--- /dev/null
+++ b/vendor/qoi/src/encode.rs
@@ -0,0 +1,210 @@
+#[cfg(any(feature = "std", feature = "alloc"))]
+use alloc::{vec, vec::Vec};
+use core::convert::TryFrom;
+#[cfg(feature = "std")]
+use std::io::Write;
+
+use bytemuck::Pod;
+
+use crate::consts::{QOI_HEADER_SIZE, QOI_OP_INDEX, QOI_OP_RUN, QOI_PADDING, QOI_PADDING_SIZE};
+use crate::error::{Error, Result};
+use crate::header::Header;
+use crate::pixel::{Pixel, SupportedChannels};
+use crate::types::{Channels, ColorSpace};
+#[cfg(feature = "std")]
+use crate::utils::GenericWriter;
+use crate::utils::{unlikely, BytesMut, Writer};
+
+#[allow(clippy::cast_possible_truncation, unused_assignments, unused_variables)]
+fn encode_impl<W: Writer, const N: usize>(mut buf: W, data: &[u8]) -> Result<usize>
+where
+    Pixel<N>: SupportedChannels,
+    [u8; N]: Pod,
+{
+    let cap = buf.capacity();
+
+    let mut index = [Pixel::new(); 256];
+    let mut px_prev = Pixel::new().with_a(0xff);
+    let mut hash_prev = px_prev.hash_index();
+    let mut run = 0_u8;
+    let mut px = Pixel::<N>::new().with_a(0xff);
+    let mut index_allowed = false;
+
+    let n_pixels = data.len() / N;
+
+    for (i, chunk) in data.chunks_exact(N).enumerate() {
+        px.read(chunk);
+        if px == px_prev {
+            run += 1;
+            if run == 62 || unlikely(i == n_pixels - 1) {
+                buf = buf.write_one(QOI_OP_RUN | (run - 1))?;
+                run = 0;
+            }
+        } else {
+            if run != 0 {
+                #[cfg(not(feature = "reference"))]
+                {
+                    // credits for the original idea: @zakarumych (had to be fixed though)
+                    buf = buf.write_one(if run == 1 && index_allowed {
+                        QOI_OP_INDEX | hash_prev
+                    } else {
+                        QOI_OP_RUN | (run - 1)
+                    })?;
+                }
+                #[cfg(feature = "reference")]
+                {
+                    buf = buf.write_one(QOI_OP_RUN | (run - 1))?;
+                }
+                run = 0;
+            }
+            index_allowed = true;
+            let px_rgba = px.as_rgba(0xff);
+            hash_prev = px_rgba.hash_index();
+            let index_px = &mut index[hash_prev as usize];
+            if *index_px == px_rgba {
+                buf = buf.write_one(QOI_OP_INDEX | hash_prev)?;
+            } else {
+                *index_px = px_rgba;
+                buf = px.encode_into(px_prev, buf)?;
+            }
+            px_prev = px;
+        }
+    }
+
+    buf = buf.write_many(&QOI_PADDING)?;
+    Ok(cap.saturating_sub(buf.capacity()))
+}
+
+#[inline]
+fn encode_impl_all<W: Writer>(out: W, data: &[u8], channels: Channels) -> Result<usize> {
+    match channels {
+        Channels::Rgb => encode_impl::<_, 3>(out, data),
+        Channels::Rgba => encode_impl::<_, 4>(out, data),
+    }
+}
+
+/// The maximum number of bytes the encoded image will take.
+///
+/// Can be used to pre-allocate the buffer to encode the image into.
+#[inline]
+pub fn encode_max_len(width: u32, height: u32, channels: impl Into<u8>) -> usize {
+    let (width, height) = (width as usize, height as usize);
+    let n_pixels = width.saturating_mul(height);
+    QOI_HEADER_SIZE
+        + n_pixels.saturating_mul(channels.into() as usize)
+        + n_pixels
+        + QOI_PADDING_SIZE
+}
+
+/// Encode the image into a pre-allocated buffer.
+///
+/// Returns the total number of bytes written.
+#[inline]
+pub fn encode_to_buf(
+    buf: impl AsMut<[u8]>, data: impl AsRef<[u8]>, width: u32, height: u32,
+) -> Result<usize> {
+    Encoder::new(&data, width, height)?.encode_to_buf(buf)
+}
+
+/// Encode the image into a newly allocated vector.
+#[cfg(any(feature = "alloc", feature = "std"))]
+#[inline]
+pub fn encode_to_vec(data: impl AsRef<[u8]>, width: u32, height: u32) -> Result<Vec<u8>> {
+    Encoder::new(&data, width, height)?.encode_to_vec()
+}
+
+/// Encode QOI images into buffers or into streams.
+pub struct Encoder<'a> {
+    data: &'a [u8],
+    header: Header,
+}
+
+impl<'a> Encoder<'a> {
+    /// Creates a new encoder from a given array of pixel data and image dimensions.
+    ///
+    /// The number of channels will be inferred automatically (the valid values
+    /// are 3 or 4). The color space will be set to sRGB by default.
+    #[inline]
+    #[allow(clippy::cast_possible_truncation)]
+    pub fn new(data: &'a (impl AsRef<[u8]> + ?Sized), width: u32, height: u32) -> Result<Self> {
+        let data = data.as_ref();
+        let mut header =
+            Header::try_new(width, height, Channels::default(), ColorSpace::default())?;
+        let size = data.len();
+        let n_channels = size / header.n_pixels();
+        if header.n_pixels() * n_channels != size {
+            return Err(Error::InvalidImageLength { size, width, height });
+        }
+        header.channels = Channels::try_from(n_channels.min(0xff) as u8)?;
+        Ok(Self { data, header })
+    }
+
+    /// Returns a new encoder with modified color space.
+    ///
+    /// Note: the color space doesn't affect encoding or decoding in any way, it's
+    /// a purely informative field that's stored in the image header.
+    #[inline]
+    pub const fn with_colorspace(mut self, colorspace: ColorSpace) -> Self {
+        self.header = self.header.with_colorspace(colorspace);
+        self
+    }
+
+    /// Returns the inferred number of channels.
+    #[inline]
+    pub const fn channels(&self) -> Channels {
+        self.header.channels
+    }
+
+    /// Returns the header that will be stored in the encoded image.
+    #[inline]
+    pub const fn header(&self) -> &Header {
+        &self.header
+    }
+
+    /// The maximum number of bytes the encoded image will take.
+    ///
+    /// Can be used to pre-allocate the buffer to encode the image into.
+    #[inline]
+    pub fn required_buf_len(&self) -> usize {
+        self.header.encode_max_len()
+    }
+
+    /// Encodes the image to a pre-allocated buffer and returns the number of bytes written.
+    ///
+    /// The minimum size of the buffer can be found via [`Encoder::required_buf_len`].
+    #[inline]
+    pub fn encode_to_buf(&self, mut buf: impl AsMut<[u8]>) -> Result<usize> {
+        let buf = buf.as_mut();
+        let size_required = self.required_buf_len();
+        if unlikely(buf.len() < size_required) {
+            return Err(Error::OutputBufferTooSmall { size: buf.len(), required: size_required });
+        }
+        let (head, tail) = buf.split_at_mut(QOI_HEADER_SIZE); // can't panic
+        head.copy_from_slice(&self.header.encode());
+        let n_written = encode_impl_all(BytesMut::new(tail), self.data, self.header.channels)?;
+        Ok(QOI_HEADER_SIZE + n_written)
+    }
+
+    /// Encodes the image into a newly allocated vector of bytes and returns it.
+    #[cfg(any(feature = "alloc", feature = "std"))]
+    #[inline]
+    pub fn encode_to_vec(&self) -> Result<Vec<u8>> {
+        let mut out = vec![0_u8; self.required_buf_len()];
+        let size = self.encode_to_buf(&mut out)?;
+        out.truncate(size);
+        Ok(out)
+    }
+
+    /// Encodes the image directly to a generic writer that implements [`Write`](std::io::Write).
+    ///
+    /// Note: while it's possible to pass a `&mut [u8]` slice here since it implements `Write`,
+    /// it would more effficient to use a specialized method instead: [`Encoder::encode_to_buf`].
+    #[cfg(feature = "std")]
+    #[inline]
+    pub fn encode_to_stream<W: Write>(&self, writer: &mut W) -> Result<usize> {
+        writer.write_all(&self.header.encode())?;
+        let n_written =
+            encode_impl_all(GenericWriter::new(writer), self.data, self.header.channels)?;
+        Ok(n_written + QOI_HEADER_SIZE)
+    }
+}