1 files changed, 120 insertions, 0 deletions
diff --git a/vendor/qoi/src/header.rs b/vendor/qoi/src/header.rs
new file mode 100644
index 0000000..ccdb1cc
--- /dev/null
+++ b/vendor/qoi/src/header.rs
@@ -0,0 +1,120 @@
+use core::convert::TryInto;
+
+use bytemuck::cast_slice;
+
+use crate::consts::{QOI_HEADER_SIZE, QOI_MAGIC, QOI_PIXELS_MAX};
+use crate::encode_max_len;
+use crate::error::{Error, Result};
+use crate::types::{Channels, ColorSpace};
+use crate::utils::unlikely;
+
+/// Image header: dimensions, channels, color space.
+///
+/// ### Notes
+/// A valid image header must satisfy the following conditions:
+/// * Both width and height must be non-zero.
+/// * Maximum number of pixels is 400Mp (=4e8 pixels).
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Header {
+    /// Image width in pixels
+    pub width: u32,
+    /// Image height in pixels
+    pub height: u32,
+    /// Number of 8-bit channels per pixel
+    pub channels: Channels,
+    /// Color space (informative field, doesn't affect encoding)
+    pub colorspace: ColorSpace,
+}
+
+impl Default for Header {
+    #[inline]
+    fn default() -> Self {
+        Self {
+            width: 1,
+            height: 1,
+            channels: Channels::default(),
+            colorspace: ColorSpace::default(),
+        }
+    }
+}
+
+impl Header {
+    /// Creates a new header and validates image dimensions.
+    #[inline]
+    pub const fn try_new(
+        width: u32, height: u32, channels: Channels, colorspace: ColorSpace,
+    ) -> Result<Self> {
+        let n_pixels = (width as usize).saturating_mul(height as usize);
+        if unlikely(n_pixels == 0 || n_pixels > QOI_PIXELS_MAX) {
+            return Err(Error::InvalidImageDimensions { width, height });
+        }
+        Ok(Self { width, height, channels, colorspace })
+    }
+
+    /// Creates a new header with modified channels.
+    #[inline]
+    pub const fn with_channels(mut self, channels: Channels) -> Self {
+        self.channels = channels;
+        self
+    }
+
+    /// Creates a new header with modified color space.
+    #[inline]
+    pub const fn with_colorspace(mut self, colorspace: ColorSpace) -> Self {
+        self.colorspace = colorspace;
+        self
+    }
+
+    /// Serializes the header into a bytes array.
+    #[inline]
+    pub(crate) fn encode(&self) -> [u8; QOI_HEADER_SIZE] {
+        let mut out = [0; QOI_HEADER_SIZE];
+        out[..4].copy_from_slice(&QOI_MAGIC.to_be_bytes());
+        out[4..8].copy_from_slice(&self.width.to_be_bytes());
+        out[8..12].copy_from_slice(&self.height.to_be_bytes());
+        out[12] = self.channels.into();
+        out[13] = self.colorspace.into();
+        out
+    }
+
+    /// Deserializes the header from a byte array.
+    #[inline]
+    pub(crate) fn decode(data: impl AsRef<[u8]>) -> Result<Self> {
+        let data = data.as_ref();
+        if unlikely(data.len() < QOI_HEADER_SIZE) {
+            return Err(Error::UnexpectedBufferEnd);
+        }
+        let v = cast_slice::<_, [u8; 4]>(&data[..12]);
+        let magic = u32::from_be_bytes(v[0]);
+        let width = u32::from_be_bytes(v[1]);
+        let height = u32::from_be_bytes(v[2]);
+        let channels = data[12].try_into()?;
+        let colorspace = data[13].try_into()?;
+        if unlikely(magic != QOI_MAGIC) {
+            return Err(Error::InvalidMagic { magic });
+        }
+        Self::try_new(width, height, channels, colorspace)
+    }
+
+    /// Returns a number of pixels in the image.
+    #[inline]
+    pub const fn n_pixels(&self) -> usize {
+        (self.width as usize).saturating_mul(self.height as usize)
+    }
+
+    /// Returns the total number of bytes in the raw pixel array.
+    ///
+    /// This may come useful when pre-allocating a buffer to decode the image into.
+    #[inline]
+    pub const fn n_bytes(&self) -> usize {
+        self.n_pixels() * self.channels.as_u8() as usize
+    }
+
+    /// 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(&self) -> usize {
+        encode_max_len(self.width, self.height, self.channels)
+    }
+}