Add benchmark for neuquant

benches/neuquant.rs

@@ -0,0 +1,56 @@
+#![feature(test)]
+
+extern crate color_quant;
+extern crate test;
+
+use color_quant::NeuQuant;
+use test::{black_box, Bencher};
+
+fn make_pixels() -> Vec<u8> {
+    let mut pixels = vec![0; 4 * 256 * 256];
+    let mut r: u8 = 0;
+    let mut g: u8 = 0;
+    let mut b: u8 = 0;
+
+    for (i, p) in pixels.iter_mut().enumerate() {
+        match i % 4 {
+            0 => *p = r,
+            1 => *p = g,
+            2 => {
+                *p = b;
+                if let Some(next_r) = r.checked_add(1) {
+                    r = next_r;
+                    continue;
+                }
+                r = 0;
+                if let Some(next_g) = g.checked_add(1) {
+                    g = next_g;
+                    continue;
+                }
+                g = 0;
+                b += 1
+            }
+            3 => *p = 255,
+            _ => unreachable!(),
+        }
+    }
+    pixels
+}
+
+#[bench]
+fn bench_map_pixel(b: &mut Bencher) {
+    let pixels = make_pixels();
+    let nq = NeuQuant::new(10, 256, &pixels);
+    let mut i = 0u8;
+    b.iter(|| {
+        i = i.wrapping_add(1);
+        let mut color = black_box([123, i, 4, 255]);
+        nq.map_pixel(&mut color[..]);
+    })
+}
+
+#[bench]
+fn bench_new_nq(b: &mut Bencher) {
+    let pixels = make_pixels();
+    b.iter(|| NeuQuant::new(10, 128, &pixels));
+}