add bool to fixed conversion

README.md

@@ -34,7 +34,7 @@ fixed-point numbers, and in the range 0 ≤ *x* < 1 for unsigned
 fixed-point numbers.
 
 All lossless infallible conversions between fixed-point numbers and
-integer primitives are implemented. That is, you can use [`From`] or
+numeric primitives are implemented. That is, you can use [`From`] or
 [`Into`] for the conversions that always work without losing any bits.
 
 ## What’s new
@@ -42,7 +42,7 @@ integer primitives are implemented. That is, you can use [`From`] or
 ### Version 0.1.5 (unreleased)
 
   * Lossless infallible conversions between fixed-point numbers and
-    integer primitives are now supported using [`From`] and [`Into`].
+    numeric primitives are now supported using [`From`] and [`Into`].
 
 ### Version 0.1.4 news (2018-11-29)
 

RELEASES.md

@@ -9,7 +9,7 @@ Version 0.1.5 (unreleased)
 ==========================
 
   * Lossless infallible conversions between fixed-point numbers and
-    integer primitives are now supported using `From` and `Into`.
+    numeric primitives are now supported using `From` and `Into`.
 
 Version 0.1.4 (2018-11-29)
 ==========================

src/convert.rs

@@ -14,7 +14,7 @@
 // <https://opensource.org/licenses/MIT>.
 
 use core::ops::{Add, Sub};
-use frac::{IsGreaterOrEqual, IsLessOrEqual, True, Unsigned, U0, U1, U128, U16, U32, U64, U8};
+use frac::{IsGreaterOrEqual, IsLessOrEqual, True, Unsigned, U0, U1, U128, U16, U2, U32, U64, U8};
 use {
     FixedI128, FixedI16, FixedI32, FixedI64, FixedI8, FixedU128, FixedU16, FixedU32, FixedU64,
     FixedU8,
@@ -189,6 +189,46 @@ prim_to_fixed! { (u64, i64, U64) -> (FixedU128, FixedI128, U128) }
 
 prim_to_fixed! { (u128, i128) -> (FixedU128, FixedI128) }
 
+macro_rules! bool_to_fixed {
+    ($DstU:ident, $DstI:ident, $DstBits:ident) => {
+        // Condition: FracDst <= $DstBits - 1
+        impl<FracDst> From<bool> for $DstU<FracDst>
+        where
+            FracDst: Unsigned
+                + IsLessOrEqual<$DstBits, Output = True>
+                + IsLessOrEqual<<$DstBits as Sub<U1>>::Output, Output = True>,
+        {
+            #[inline]
+            fn from(src: bool) -> $DstU<FracDst> {
+                let unshifted = $DstU::<FracDst>::from_bits(src.into()).to_bits();
+                let shift = FracDst::to_u32();
+                $DstU::<FracDst>::from_bits(unshifted << shift)
+            }
+        }
+
+        // Condition: FracDst <= $DstBits - 2
+        impl<FracDst> From<bool> for $DstI<FracDst>
+        where
+            FracDst: Unsigned
+                + IsLessOrEqual<$DstBits, Output = True>
+                + IsLessOrEqual<<$DstBits as Sub<U2>>::Output, Output = True>,
+        {
+            #[inline]
+            fn from(src: bool) -> $DstI<FracDst> {
+                let unshifted = $DstI::<FracDst>::from_bits(src.into()).to_bits();
+                let shift = FracDst::to_u32();
+                $DstI::<FracDst>::from_bits(unshifted << shift)
+            }
+        }
+    };
+}
+
+bool_to_fixed! { FixedU8, FixedI8, U8 }
+bool_to_fixed! { FixedU16, FixedI16, U16 }
+bool_to_fixed! { FixedU32, FixedI32, U32 }
+bool_to_fixed! { FixedU64, FixedI64, U64 }
+bool_to_fixed! { FixedU128, FixedI128, U128 }
+
 macro_rules! fixed_to_prim {
     (($SrcU:ident, $SrcI:ident) -> ($DstU:ident, $DstI:ident)) => {
         impl From<$SrcU<U0>> for $DstU {
@@ -388,6 +428,14 @@ mod tests {
         }
     }
 
+    #[test]
+    fn from_bool() {
+        assert_eq!(FixedI8::<frac::U6>::from(true), 1);
+        assert_eq!(FixedI8::<frac::U6>::from(false), 0);
+        assert_eq!(FixedI128::<frac::U64>::from(true), 1);
+        assert_eq!(FixedU128::<frac::U127>::from(true), 1);
+    }
+
     #[test]
     fn signed_from_f32() {
         type Fix = FixedI8<frac::U4>;

src/lib.rs

@@ -43,7 +43,7 @@ fixed-point numbers, and in the range 0 ≤ *x* < 1 for unsigned
 fixed-point numbers.
 
 All lossless infallible conversions between fixed-point numbers and
-integer primitives are implemented. That is, you can use [`From`] or
+numeric primitives are implemented. That is, you can use [`From`] or
 [`Into`] for the conversions that always work without losing any bits.
 
 ## Quick example