1 files changed, 183 insertions, 0 deletions
diff --git a/vendor/qoi/src/pixel.rs b/vendor/qoi/src/pixel.rs
new file mode 100644
index 0000000..d103494
--- /dev/null
+++ b/vendor/qoi/src/pixel.rs
@@ -0,0 +1,183 @@
+use crate::consts::{QOI_OP_DIFF, QOI_OP_LUMA, QOI_OP_RGB, QOI_OP_RGBA};
+use crate::error::Result;
+use crate::utils::Writer;
+use bytemuck::{cast, Pod};
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[repr(transparent)]
+pub struct Pixel<const N: usize>([u8; N]);
+
+impl<const N: usize> Pixel<N> {
+    #[inline]
+    pub const fn new() -> Self {
+        Self([0; N])
+    }
+
+    #[inline]
+    pub fn read(&mut self, s: &[u8]) {
+        if s.len() == N {
+            let mut i = 0;
+            while i < N {
+                self.0[i] = s[i];
+                i += 1;
+            }
+        } else {
+            unreachable!();
+        }
+    }
+
+    #[inline]
+    pub fn update<const M: usize>(&mut self, px: Pixel<M>) {
+        let mut i = 0;
+        while i < M && i < N {
+            self.0[i] = px.0[i];
+            i += 1;
+        }
+    }
+
+    #[inline]
+    pub fn update_rgb(&mut self, r: u8, g: u8, b: u8) {
+        self.0[0] = r;
+        self.0[1] = g;
+        self.0[2] = b;
+    }
+
+    #[inline]
+    pub fn update_rgba(&mut self, r: u8, g: u8, b: u8, a: u8) {
+        self.0[0] = r;
+        self.0[1] = g;
+        self.0[2] = b;
+        if N >= 4 {
+            self.0[3] = a;
+        }
+    }
+
+    #[inline]
+    pub fn update_diff(&mut self, b1: u8) {
+        self.0[0] = self.0[0].wrapping_add((b1 >> 4) & 0x03).wrapping_sub(2);
+        self.0[1] = self.0[1].wrapping_add((b1 >> 2) & 0x03).wrapping_sub(2);
+        self.0[2] = self.0[2].wrapping_add(b1 & 0x03).wrapping_sub(2);
+    }
+
+    #[inline]
+    pub fn update_luma(&mut self, b1: u8, b2: u8) {
+        let vg = (b1 & 0x3f).wrapping_sub(32);
+        let vg_8 = vg.wrapping_sub(8);
+        let vr = vg_8.wrapping_add((b2 >> 4) & 0x0f);
+        let vb = vg_8.wrapping_add(b2 & 0x0f);
+        self.0[0] = self.0[0].wrapping_add(vr);
+        self.0[1] = self.0[1].wrapping_add(vg);
+        self.0[2] = self.0[2].wrapping_add(vb);
+    }
+
+    #[inline]
+    pub const fn as_rgba(self, with_a: u8) -> Pixel<4> {
+        let mut i = 0;
+        let mut out = Pixel::new();
+        while i < N {
+            out.0[i] = self.0[i];
+            i += 1;
+        }
+        if N < 4 {
+            out.0[3] = with_a;
+        }
+        out
+    }
+
+    #[inline]
+    pub const fn r(self) -> u8 {
+        self.0[0]
+    }
+
+    #[inline]
+    pub const fn g(self) -> u8 {
+        self.0[1]
+    }
+
+    #[inline]
+    pub const fn b(self) -> u8 {
+        self.0[2]
+    }
+
+    #[inline]
+    pub const fn with_a(mut self, value: u8) -> Self {
+        if N >= 4 {
+            self.0[3] = value;
+        }
+        self
+    }
+
+    #[inline]
+    pub const fn a_or(self, value: u8) -> u8 {
+        if N < 4 {
+            value
+        } else {
+            self.0[3]
+        }
+    }
+
+    #[inline]
+    #[allow(clippy::cast_lossless, clippy::cast_possible_truncation)]
+    pub fn hash_index(self) -> u8
+    where
+        [u8; N]: Pod,
+    {
+        // credits for the initial idea: @zakarumych
+        let v = if N == 4 {
+            u32::from_ne_bytes(cast(self.0))
+        } else {
+            u32::from_ne_bytes([self.0[0], self.0[1], self.0[2], 0xff])
+        } as u64;
+        let s = ((v & 0xff00_ff00) << 32) | (v & 0x00ff_00ff);
+        s.wrapping_mul(0x0300_0700_0005_000b_u64).to_le().swap_bytes() as u8 & 63
+    }
+
+    #[inline]
+    pub fn rgb_add(&mut self, r: u8, g: u8, b: u8) {
+        self.0[0] = self.0[0].wrapping_add(r);
+        self.0[1] = self.0[1].wrapping_add(g);
+        self.0[2] = self.0[2].wrapping_add(b);
+    }
+
+    #[inline]
+    pub fn encode_into<W: Writer>(&self, px_prev: Self, buf: W) -> Result<W> {
+        if N == 3 || self.a_or(0) == px_prev.a_or(0) {
+            let vg = self.g().wrapping_sub(px_prev.g());
+            let vg_32 = vg.wrapping_add(32);
+            if vg_32 | 63 == 63 {
+                let vr = self.r().wrapping_sub(px_prev.r());
+                let vb = self.b().wrapping_sub(px_prev.b());
+                let vg_r = vr.wrapping_sub(vg);
+                let vg_b = vb.wrapping_sub(vg);
+                let (vr_2, vg_2, vb_2) =
+                    (vr.wrapping_add(2), vg.wrapping_add(2), vb.wrapping_add(2));
+                if vr_2 | vg_2 | vb_2 | 3 == 3 {
+                    buf.write_one(QOI_OP_DIFF | vr_2 << 4 | vg_2 << 2 | vb_2)
+                } else {
+                    let (vg_r_8, vg_b_8) = (vg_r.wrapping_add(8), vg_b.wrapping_add(8));
+                    if vg_r_8 | vg_b_8 | 15 == 15 {
+                        buf.write_many(&[QOI_OP_LUMA | vg_32, vg_r_8 << 4 | vg_b_8])
+                    } else {
+                        buf.write_many(&[QOI_OP_RGB, self.r(), self.g(), self.b()])
+                    }
+                }
+            } else {
+                buf.write_many(&[QOI_OP_RGB, self.r(), self.g(), self.b()])
+            }
+        } else {
+            buf.write_many(&[QOI_OP_RGBA, self.r(), self.g(), self.b(), self.a_or(0xff)])
+        }
+    }
+}
+
+impl<const N: usize> From<Pixel<N>> for [u8; N] {
+    #[inline(always)]
+    fn from(px: Pixel<N>) -> Self {
+        px.0
+    }
+}
+
+pub trait SupportedChannels {}
+
+impl SupportedChannels for Pixel<3> {}
+impl SupportedChannels for Pixel<4> {}