Copy of spark crate.

src/spark.rs

@@ -0,0 +1,44 @@
+use std::f32::MAX as f32_max;
+
+/// `graph` generates a string representation of the values as a sparkline.
+///
+/// # Arguments
+///
+/// * `values` - The values to graph.
+///
+/// # Example
+///
+/// ```rust
+/// let sparkline = spark::graph(&[1.0, 5.0, 22.0, 13.0, 53.0]);
+/// assert_eq!(sparkline, "▁▁▃▂█");
+/// ```
+pub fn graph(values: &[f32]) -> String {
+    let ticks = "▁▂▃▄▅▆▇█";
+
+    /* XXX: This doesn't feel like idiomatic Rust */
+    let mut min: f32 = f32_max;
+    let mut max: f32 = 0.0;
+
+    for &i in values.iter() {
+        if i > max {
+            max = i;
+        }
+        if i < min {
+            min = i;
+        }
+    }
+
+    let ratio = if max == min {
+        1.0
+    } else {
+        (ticks.chars().count() - 1) as f32 / (max - min)
+    };
+
+    values
+        .iter()
+        .cloned()
+        .map(|n| (n - min) * ratio)
+        .map(|n| n.floor() as usize)
+        .filter_map(|n| ticks.chars().nth(n))
+        .collect()
+}