1 files changed, 104 insertions, 0 deletions
diff --git a/src/format.rs b/src/format.rs
new file mode 100755
index 0000000..984f0f5
--- /dev/null
+++ b/src/format.rs
@@ -0,0 +1,104 @@
+pub fn change(pct: f64, signed: bool) -> String {
+    if signed {
+        format!("{:>+6}%", signed_short(pct * 1e2))
+    } else {
+        format!("{:>6}%", short(pct * 1e2))
+    }
+}
+
+pub fn time(ns: f64) -> String {
+    if ns < 1.0 {
+        format!("{:>6} ps", short(ns * 1e3))
+    } else if ns < 10f64.powi(3) {
+        format!("{:>6} ns", short(ns))
+    } else if ns < 10f64.powi(6) {
+        format!("{:>6} us", short(ns / 1e3))
+    } else if ns < 10f64.powi(9) {
+        format!("{:>6} ms", short(ns / 1e6))
+    } else {
+        format!("{:>6} s", short(ns / 1e9))
+    }
+}
+
+pub fn short(n: f64) -> String {
+    if n < 10.0 {
+        format!("{:.4}", n)
+    } else if n < 100.0 {
+        format!("{:.3}", n)
+    } else if n < 1000.0 {
+        format!("{:.2}", n)
+    } else if n < 10000.0 {
+        format!("{:.1}", n)
+    } else {
+        format!("{:.0}", n)
+    }
+}
+
+fn signed_short(n: f64) -> String {
+    let n_abs = n.abs();
+
+    if n_abs < 10.0 {
+        format!("{:+.4}", n)
+    } else if n_abs < 100.0 {
+        format!("{:+.3}", n)
+    } else if n_abs < 1000.0 {
+        format!("{:+.2}", n)
+    } else if n_abs < 10000.0 {
+        format!("{:+.1}", n)
+    } else {
+        format!("{:+.0}", n)
+    }
+}
+
+pub fn iter_count(iterations: u64) -> String {
+    if iterations < 10_000 {
+        format!("{} iterations", iterations)
+    } else if iterations < 1_000_000 {
+        format!("{:.0}k iterations", (iterations as f64) / 1000.0)
+    } else if iterations < 10_000_000 {
+        format!("{:.1}M iterations", (iterations as f64) / (1000.0 * 1000.0))
+    } else if iterations < 1_000_000_000 {
+        format!("{:.0}M iterations", (iterations as f64) / (1000.0 * 1000.0))
+    } else if iterations < 10_000_000_000 {
+        format!(
+            "{:.1}B iterations",
+            (iterations as f64) / (1000.0 * 1000.0 * 1000.0)
+        )
+    } else {
+        format!(
+            "{:.0}B iterations",
+            (iterations as f64) / (1000.0 * 1000.0 * 1000.0)
+        )
+    }
+}
+
+pub fn integer(n: f64) -> String {
+    format!("{}", n as u64)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn short_max_len() {
+        let mut float = 1.0;
+        while float < 999_999.9 {
+            let string = short(float);
+            println!("{}", string);
+            assert!(string.len() <= 6);
+            float *= 2.0;
+        }
+    }
+
+    #[test]
+    fn signed_short_max_len() {
+        let mut float = -1.0;
+        while float > -999_999.9 {
+            let string = signed_short(float);
+            println!("{}", string);
+            assert!(string.len() <= 7);
+            float *= 2.0;
+        }
+    }
+}