pub fn atanh(self) -> f32 {
0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
}
+
+ /// Raw transmutation to `u32`.
+ ///
+ /// Converts the `f32` into its raw memory representation,
+ /// similar to the `transmute` function.
+ ///
+ /// Note that this function is distinct from casting.
+ ///
+ /// ```
+ /// #![feature(float_bits_conv)]
+ /// assert!((1f32).to_bits() != 1f32 as u32); // to_bits() is not casting!
+ /// assert_eq!((12.5f32).to_bits(), 0x41480000);
+ ///
+ /// ```
+ #[unstable(feature = "float_bits_conv", reason = "recently added", issue = "0")]
+ #[inline]
+ pub fn to_bits(self) -> u32 {
+ unsafe { ::mem::transmute(self) }
+ }
+
+ /// Raw transmutation from `u32`.
+ ///
+ /// Converts the given `u32` containing the float's raw memory
+ /// representation into the `f32` type, similar to the
+ /// `transmute` function.
+ ///
+ /// Note that this function is distinct from casting.
+ ///
+ /// ```
+ /// #![feature(float_bits_conv)]
+ /// use std::f32;
+ /// let difference = (f32::from_bits(0x41480000) - 12.5).abs();
+ /// assert!(difference <= 1e-5);
+ /// ```
+ #[unstable(feature = "float_bits_conv", reason = "recently added", issue = "0")]
+ #[inline]
+ pub fn from_bits(v: u32) -> Self {
+ unsafe { ::mem::transmute(v) }
+ }
}
#[cfg(test)]
assert_approx_eq!(ln_2, 2f32.ln());
assert_approx_eq!(ln_10, 10f32.ln());
}
+
+ #[test]
+ fn test_float_bits_conv() {
+ assert_eq!((1f32).to_bits(), 0x3f800000);
+ assert_eq!((12.5f32).to_bits(), 0x41480000);
+ assert_eq!((1337f32).to_bits(), 0x44a72000);
+ assert_eq!((-14.25f32).to_bits(), 0xc1640000);
+ assert_approx_eq!(f32::from_bits(0x3f800000), 1.0);
+ assert_approx_eq!(f32::from_bits(0x41480000), 12.5);
+ assert_approx_eq!(f32::from_bits(0x44a72000), 1337.0);
+ assert_approx_eq!(f32::from_bits(0xc1640000), -14.25);
+ }
}
}
}
}
+
+ /// Raw transmutation to `u64`.
+ ///
+ /// Converts the `f64` into its raw memory representation,
+ /// similar to the `transmute` function.
+ ///
+ /// Note that this function is distinct from casting.
+ ///
+ /// ```
+ /// #![feature(float_bits_conv)]
+ /// assert!((1f64).to_bits() != 1f64 as u64); // to_bits() is not casting!
+ /// assert_eq!((12.5f64).to_bits(), 0x4029000000000000);
+ ///
+ /// ```
+ #[unstable(feature = "float_bits_conv", reason = "recently added", issue = "0")]
+ #[inline]
+ pub fn to_bits(self) -> u64 {
+ unsafe { ::mem::transmute(self) }
+ }
+
+ /// Raw transmutation from `u64`.
+ ///
+ /// Converts the given `u64` containing the float's raw memory
+ /// representation into the `f64` type, similar to the
+ /// `transmute` function.
+ ///
+ /// Note that this function is distinct from casting.
+ ///
+ /// ```
+ /// #![feature(float_bits_conv)]
+ /// use std::f64;
+ /// let difference = (f64::from_bits(0x4029000000000000) - 12.5).abs();
+ /// assert!(difference <= 1e-5);
+ /// ```
+ #[unstable(feature = "float_bits_conv", reason = "recently added", issue = "0")]
+ #[inline]
+ pub fn from_bits(v: u64) -> Self {
+ unsafe { ::mem::transmute(v) }
+ }
}
#[cfg(test)]
assert_approx_eq!(ln_2, 2f64.ln());
assert_approx_eq!(ln_10, 10f64.ln());
}
+
+ #[test]
+ fn test_float_bits_conv() {
+ assert_eq!((1f64).to_bits(), 0x3ff0000000000000);
+ assert_eq!((12.5f64).to_bits(), 0x4029000000000000);
+ assert_eq!((1337f64).to_bits(), 0x4094e40000000000);
+ assert_eq!((-14.25f64).to_bits(), 0xc02c800000000000);
+ assert_approx_eq!(f64::from_bits(0x3ff0000000000000), 1.0);
+ assert_approx_eq!(f64::from_bits(0x4029000000000000), 12.5);
+ assert_approx_eq!(f64::from_bits(0x4094e40000000000), 1337.0);
+ assert_approx_eq!(f64::from_bits(0xc02c800000000000), -14.25);
+ }
}
#![feature(zero_one)]
#![cfg_attr(test, feature(update_panic_count))]
#![cfg_attr(stage0, feature(pub_restricted))]
+#![cfg_attr(test, feature(float_bits_conv))]
// Explicitly import the prelude. The compiler uses this same unstable attribute
// to import the prelude implicitly when building crates that depend on std.