From 99873d06e53c0de622829cb0517757b4bd510327 Mon Sep 17 00:00:00 2001
From: Sam Cappleman-Lynes <sam.capplemanlynes@gmail.com>
Date: Thu, 29 Jun 2017 18:29:14 +0100
Subject: [PATCH] Scalar operations on integer types up to 32 bits

---
 bigint/src/bigint.rs  |  5 ++++
 bigint/src/biguint.rs |  5 ++++
 bigint/src/macros.rs  | 63 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+)

diff --git a/bigint/src/bigint.rs b/bigint/src/bigint.rs
index 848eb09..ff68886 100644
--- a/bigint/src/bigint.rs
+++ b/bigint/src/bigint.rs
@@ -370,6 +370,7 @@ impl Add<BigInt> for BigInt {
     }
 }
 
+promote_all_scalars!(impl Add for BigInt, add);
 forward_all_scalar_binop_to_val_val_commutative!(impl Add<BigDigit> for BigInt, add);
 
 impl Add<BigDigit> for BigInt {
@@ -468,6 +469,7 @@ impl Sub<BigInt> for BigInt {
     }
 }
 
+promote_all_scalars!(impl Sub for BigInt, sub);
 forward_all_scalar_binop_to_val_val!(impl Sub<BigDigit> for BigInt, sub);
 
 impl Sub<BigDigit> for BigInt {
@@ -536,6 +538,7 @@ impl<'a, 'b> Mul<&'b BigInt> for &'a BigInt {
     }
 }
 
+promote_all_scalars!(impl Mul for BigInt, mul);
 forward_all_scalar_binop_to_val_val_commutative!(impl Mul<BigDigit> for BigInt, mul);
 
 impl Mul<BigDigit> for BigInt {
@@ -574,6 +577,7 @@ impl<'a, 'b> Div<&'b BigInt> for &'a BigInt {
     }
 }
 
+promote_all_scalars!(impl Div for BigInt, div);
 forward_all_scalar_binop_to_val_val!(impl Div<BigDigit> for BigInt, div);
 
 impl Div<BigDigit> for BigInt {
@@ -634,6 +638,7 @@ impl<'a, 'b> Rem<&'b BigInt> for &'a BigInt {
     }
 }
 
+promote_all_scalars!(impl Rem for BigInt, rem);
 forward_all_scalar_binop_to_val_val!(impl Rem<BigDigit> for BigInt, rem);
 
 impl Rem<BigDigit> for BigInt {
diff --git a/bigint/src/biguint.rs b/bigint/src/biguint.rs
index 28b6e73..6a00cbf 100644
--- a/bigint/src/biguint.rs
+++ b/bigint/src/biguint.rs
@@ -394,6 +394,7 @@ impl<'a> Add<&'a BigUint> for BigUint {
     }
 }
 
+promote_unsigned_scalars!(impl Add for BigUint, add);
 forward_all_scalar_binop_to_val_val_commutative!(impl Add<BigDigit> for BigUint, add);
 
 impl Add<BigDigit> for BigUint {
@@ -439,6 +440,7 @@ impl<'a> Sub<BigUint> for &'a BigUint {
     }
 }
 
+promote_unsigned_scalars!(impl Sub for BigUint, sub);
 forward_all_scalar_binop_to_val_val!(impl Sub<BigDigit> for BigUint, sub);
 
 impl Sub<BigDigit> for BigUint {
@@ -476,6 +478,7 @@ impl<'a, 'b> Mul<&'b BigUint> for &'a BigUint {
     }
 }
 
+promote_unsigned_scalars!(impl Mul for BigUint, mul);
 forward_all_scalar_binop_to_val_val_commutative!(impl Mul<BigDigit> for BigUint, mul);
 
 impl Mul<BigDigit> for BigUint {
@@ -507,6 +510,7 @@ impl<'a, 'b> Div<&'b BigUint> for &'a BigUint {
     }
 }
 
+promote_unsigned_scalars!(impl Div for BigUint, div);
 forward_all_scalar_binop_to_val_val!(impl Div<BigDigit> for BigUint, div);
 
 impl Div<BigDigit> for BigUint {
@@ -544,6 +548,7 @@ impl<'a, 'b> Rem<&'b BigUint> for &'a BigUint {
     }
 }
 
+promote_unsigned_scalars!(impl Rem for BigUint, rem);
 forward_all_scalar_binop_to_val_val!(impl Rem<BigDigit> for BigUint, rem);
 
 impl Rem<BigDigit> for BigUint {
diff --git a/bigint/src/macros.rs b/bigint/src/macros.rs
index f81bd84..76d805e 100644
--- a/bigint/src/macros.rs
+++ b/bigint/src/macros.rs
@@ -184,6 +184,50 @@ macro_rules! forward_scalar_ref_ref_binop {
     }
 }
 
+macro_rules! promote_scalars {
+    (impl $imp:ident<$promo:ty> for $res:ty, $method:ident, $( $scalar:ty ),*) => {
+        $(
+            forward_all_scalar_binop_to_val_val!(impl $imp<$scalar> for $res, $method);
+
+            impl $imp<$scalar> for $res {
+                type Output = $res;
+
+                #[inline]
+                fn $method(self, other: $scalar) -> $res {
+                    $imp::$method(self, other as $promo)
+                }
+            }
+
+            impl $imp<$res> for $scalar {
+                type Output = $res;
+
+                #[inline]
+                fn $method(self, other: $res) -> $res {
+                    $imp::$method(self as $promo, other)
+                }
+            }
+        )*
+    }
+}
+
+macro_rules! promote_unsigned_scalars_to_u32 {
+    (impl $imp:ident for $res:ty, $method:ident) => {
+        #[cfg(target_pointer_width = "32")]
+        promote_scalars!(impl $imp<u32> for $res, $method, u8, u16, usize);
+        #[cfg(target_pointer_width = "64")]
+        promote_scalars!(impl $imp<u32> for $res, $method, u8, u16);
+    }
+}
+
+macro_rules! promote_signed_scalars_to_i32 {
+    (impl $imp:ident for $res:ty, $method:ident) => {
+        #[cfg(target_pointer_width = "32")]
+        promote_scalars!(impl $imp<i32> for $res, $method, i8, i16, isize);
+        #[cfg(target_pointer_width = "64")]
+        promote_scalars!(impl $imp<i32> for $res, $method, i8, i16);
+    }
+}
+
 // Forward everything to ref-ref, when reusing storage is not helpful
 macro_rules! forward_all_binop_to_ref_ref {
     (impl $imp:ident for $res:ty, $method:ident) => {
@@ -224,4 +268,23 @@ macro_rules! forward_all_scalar_binop_to_val_val_commutative {
         forward_scalar_val_val_binop_commutative!(impl $imp<$scalar> for $res, $method);
         forward_all_scalar_binop_to_val_val!(impl $imp<$scalar> for $res, $method);
     }
+}
+
+macro_rules! promote_unsigned_scalars {
+    (impl $imp:ident for $res:ty, $method:ident) => {
+        promote_unsigned_scalars_to_u32!(impl $imp for $res, $method);
+    }
+}
+
+macro_rules! promote_signed_scalars {
+    (impl $imp:ident for $res:ty, $method:ident) => {
+        promote_signed_scalars_to_i32!(impl $imp for $res, $method);
+    }
+}
+
+macro_rules! promote_all_scalars {
+    (impl $imp:ident for $res:ty, $method:ident) => {
+        promote_unsigned_scalars!(impl $imp for $res, $method);
+        promote_signed_scalars!(impl $imp for $res, $method);
+    }
 }
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