Implement u128/i128 support

Cargo.toml

@@ -14,6 +14,8 @@ default = ["std"]
 # Enable this to get a std::error::Error impl for convenient use with other
 # libraries.
 std = []
+# Enable this for i128/u128 support
+x128 = []
 
 [dev-dependencies]
 quickcheck = "0.4.1"

ci/script.sh

@@ -4,6 +4,9 @@ main() {
     cross test --target $TARGET
     cross test --target $TARGET --release
 
+    [ "$TRAVIS_RUST_VERSION" -eq "nightly" ] && cross test --feature x128 --target $TARGET
+    [ "$TRAVIS_RUST_VERSION" -eq "nightly" ] && cross test --feature x128 --target $TARGET --release
+
     cross test --no-default-features --target $TARGET
     cross test --no-default-features --target $TARGET --release
 }

src/lib.rs

@@ -96,6 +96,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#![cfg_attr(feature = "x128", feature(i128_type, i128))]
+
 #[cfg(feature = "std")]
 extern crate core;
 
@@ -176,6 +178,9 @@ macro_rules! fns {
 
 fns!(f32, f64, i8, i16, i32, i64, isize, u8, u16, u32, u64, usize);
 
+#[cfg(feature = "x128")]
+fns!(i128, u128);
+
 /// `$dst` can hold any value of `$src`
 macro_rules! promotion {
     ($($src:ty => $($dst: ty),+);+;) => {
@@ -415,6 +420,54 @@ mod _64 {
     }
 }
 
+#[cfg(feature = "x128")]
+mod _x128 {
+    use {Error, From};
+
+    // Signed
+    promotion! {
+        i8    =>                              i128;
+        i16   =>                              i128;
+        i32   =>                              i128;
+        i64   =>                              i128;
+        isize =>                              i128;
+        i128  => f32, f64,                    i128;
+    }
+
+    half_promotion! {
+        i8    =>                                                              u128;
+        i16   =>                                                              u128;
+        i32   =>                                                              u128;
+        i64   =>                                                              u128;
+        isize =>                                                              u128;
+        i128  =>                                                              u128;
+    }
+
+    from_signed! {
+        i128  =>           i8, i16, i32, i64,       isize, u8, u16, u32, u64,       usize;
+    }
+
+    // Unsigned
+    promotion! {
+        u8    =>                              i128,                           u128;
+        u16   =>                              i128,                           u128;
+        u32   =>                              i128,                           u128;
+        u64   =>                              i128,                           u128;
+        usize =>                              i128,                           u128;
+        u128  =>      f64,                                                    u128;
+    }
+
+    from_unsigned! {
+        u128 => f32,       i8, i16, i32, i64, i128, isize, u8, u16, u32, u64,       usize;
+    }
+
+    // Float
+    from_float! {
+        f32  => i128, u128;
+        f64  => i128, u128;
+    }
+}
+
 // The missing piece
 impl From<f64> for f32 {
     type Output = Result<f32, Error>;

src/test.rs

@@ -50,6 +50,24 @@ promote_and_back! {
     usize => f32, f64                                                    ;
 }
 
+// TODO uncomment this once quickcheck supports Arbitrary for i128/u128
+// https://github.com/BurntSushi/quickcheck/issues/162
+/*#[cfg(feature = "x128")]
+promote_and_back! {
+    i8    =>           i128      ;
+    i16   =>           i128      ;
+    i32   =>           i128      ;
+    isize =>           i128      ;
+    i64   =>           i128      ;
+    i128  => f32, f64            ;
+    u8    =>           i128, u128;
+    u16   =>           i128, u128;
+    u32   =>           i128, u128;
+    usize =>           i128, u128;
+    u64   =>           i128, u128;
+    u128  => f32, f64            ;
+}*/
+
 // If it's Ok to cast `src` to `$dst`, it must also be Ok to cast `dst` back to
 // `$src`
 macro_rules! symmetric_cast_between {
@@ -99,6 +117,13 @@ symmetric_cast_between! {
     usize =>           i8, i16, i32, i64, isize;
 }
 
+// TODO uncomment this once quickcheck supports Arbitrary for i128/u128
+// https://github.com/BurntSushi/quickcheck/issues/162
+/*#[cfg(feature = "x128")]
+symmetric_cast_between! {
+    u128  => i8, i16, i32, isize, i64, i128;
+}*/
+
 macro_rules! from_float {
     ($($src:ident => $($dst:ident),+);+;) => {
         $(
@@ -149,3 +174,11 @@ from_float! {
     f32 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
     f64 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
 }
+
+// TODO uncomment this once quickcheck supports Arbitrary for i128/u128
+// https://github.com/BurntSushi/quickcheck/issues/162
+/*#[cfg(feature = "x128")]
+from_float! {
+    f32 => i128, u128;
+    f64 => i128, u128;
+}*/