From 8508ac10721e04e5da3599ad50c02288aac79e7e Mon Sep 17 00:00:00 2001
From: Matthew Gordon <matthew.scott.gordon@gmail.com>
Date: Mon, 10 Feb 2020 17:15:02 -0500
Subject: [PATCH] Add trait for converting real type tu u32

---
 src/realtype.rs | 61 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/src/realtype.rs b/src/realtype.rs
index 1aa2f9d..5fe4bf1 100644
--- a/src/realtype.rs
+++ b/src/realtype.rs
@@ -1,6 +1,65 @@
 use nalgebra::RealField;
 
-pub trait Real: RealField {}
+pub trait NormalizedToU32 {
+    fn normalized_to_u32(self, num_bits: usize) -> u32;
+}
+
+pub trait Real: RealField + NormalizedToU32 {}
+
+impl NormalizedToU32 for f32 {
+    fn normalized_to_u32(self, num_bits: usize) -> u32 {
+        let scale = (num_bits as f32).exp2() - 1.0;
+        (self * scale) as u32
+    }
+}
+
+impl NormalizedToU32 for f64 {
+    fn normalized_to_u32(self, num_bits: usize) -> u32 {
+        let scale = (num_bits as f64).exp2() - 1.0;
+        (self * scale) as u32
+    }
+}
 
 impl Real for f32 {}
 impl Real for f64 {}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn zero_f32_normalizes_to_zero() {
+        let target = 0.0f32;
+        assert!(target.normalized_to_u32(10) == 0);
+    }
+
+    #[test]
+    fn one_f32_normalizes_to_all_ones() {
+        let target = 1.0f32;
+        assert!(target.normalized_to_u32(10) == 0b1111111111);
+    }
+
+    #[test]
+    fn half_f32_normalizes_to_half_value() {
+        let target = 0.5f32;
+        assert!(target.normalized_to_u32(10) == 511);
+    }
+
+    #[test]
+    fn zero_f64_normalizes_to_zero() {
+        let target = 0.0f64;
+        assert!(target.normalized_to_u32(10) == 0);
+    }
+
+    #[test]
+    fn one_f64_normalizes_to_all_ones() {
+        let target = 1.0f64;
+        assert!(target.normalized_to_u32(10) == 0b1111111111);
+    }
+
+    #[test]
+    fn half_f64_normalizes_to_half_value() {
+        let target = 0.5f64;
+        assert!(target.normalized_to_u32(10) == 511);
+    }
+}