vendor/half-2.4.0/src/vec.rs - toolchain/rustc - Git at Google

 //! Contains utility functions and traits to convert between vectors of [`u16`] bits and [`f16`] or
 //! [`bf16`] vectors.
 //!
 //! The utility [`HalfBitsVecExt`] sealed extension trait is implemented for [`Vec<u16>`] vectors,
 //! while the utility [`HalfFloatVecExt`] sealed extension trait is implemented for both
 //! [`Vec<f16>`] and [`Vec<bf16>`] vectors. These traits provide efficient conversions and
 //! reinterpret casting of larger buffers of floating point values, and are automatically included
 //! in the [`prelude`][crate::prelude] module.
 //!
 //! This module is only available with the `std` or `alloc` feature.

 use super::{bf16, f16, slice::HalfFloatSliceExt};
 #[cfg(feature = "alloc")]
 #[allow(unused_imports)]
 use alloc::vec::Vec;
 use core::mem;

 /// Extensions to [`Vec<f16>`] and [`Vec<bf16>`] to support reinterpret operations.
 ///
 /// This trait is sealed and cannot be implemented outside of this crate.
 pub trait HalfFloatVecExt: private::SealedHalfFloatVec {
     /// Reinterprets a vector of [`f16`]or [`bf16`] numbers as a vector of [`u16`] bits.
     ///
     /// This is a zero-copy operation. The reinterpreted vector has the same memory location as
     /// `self`.
     ///
     /// # Examples
     ///
     /// ```rust
     /// # use half::prelude::*;
     /// let float_buffer = vec![f16::from_f32(1.), f16::from_f32(2.), f16::from_f32(3.)];
     /// let int_buffer = float_buffer.reinterpret_into();
     ///
     /// assert_eq!(int_buffer, [f16::from_f32(1.).to_bits(), f16::from_f32(2.).to_bits(), f16::from_f32(3.).to_bits()]);
     /// ```
     #[must_use]
     fn reinterpret_into(self) -> Vec<u16>;

     /// Converts all of the elements of a `[f32]` slice into a new [`f16`] or [`bf16`] vector.
     ///
     /// The conversion operation is vectorized over the slice, meaning the conversion may be more
     /// efficient than converting individual elements on some hardware that supports SIMD
     /// conversions. See [crate documentation][crate] for more information on hardware conversion
     /// support.
     ///
     /// # Examples
     /// ```rust
     /// # use half::prelude::*;
     /// let float_values = [1., 2., 3., 4.];
     /// let vec: Vec<f16> = Vec::from_f32_slice(&float_values);
     ///
     /// assert_eq!(vec, vec![f16::from_f32(1.), f16::from_f32(2.), f16::from_f32(3.), f16::from_f32(4.)]);
     /// ```
     #[must_use]
     fn from_f32_slice(slice: &[f32]) -> Self;

     /// Converts all of the elements of a `[f64]` slice into a new [`f16`] or [`bf16`] vector.
     ///
     /// The conversion operation is vectorized over the slice, meaning the conversion may be more
     /// efficient than converting individual elements on some hardware that supports SIMD
     /// conversions. See [crate documentation][crate] for more information on hardware conversion
     /// support.
     ///
     /// # Examples
     /// ```rust
     /// # use half::prelude::*;
     /// let float_values = [1., 2., 3., 4.];
     /// let vec: Vec<f16> = Vec::from_f64_slice(&float_values);
     ///
     /// assert_eq!(vec, vec![f16::from_f64(1.), f16::from_f64(2.), f16::from_f64(3.), f16::from_f64(4.)]);
     /// ```
     #[must_use]
     fn from_f64_slice(slice: &[f64]) -> Self;
 }

 /// Extensions to [`Vec<u16>`] to support reinterpret operations.
 ///
 /// This trait is sealed and cannot be implemented outside of this crate.
 pub trait HalfBitsVecExt: private::SealedHalfBitsVec {
     /// Reinterprets a vector of [`u16`] bits as a vector of [`f16`] or [`bf16`] numbers.
     ///
     /// `H` is the type to cast to, and must be either the [`f16`] or [`bf16`] type.
     ///
     /// This is a zero-copy operation. The reinterpreted vector has the same memory location as
     /// `self`.
     ///
     /// # Examples
     ///
     /// ```rust
     /// # use half::prelude::*;
     /// let int_buffer = vec![f16::from_f32(1.).to_bits(), f16::from_f32(2.).to_bits(), f16::from_f32(3.).to_bits()];
     /// let float_buffer = int_buffer.reinterpret_into::<f16>();
     ///
     /// assert_eq!(float_buffer, [f16::from_f32(1.), f16::from_f32(2.), f16::from_f32(3.)]);
     /// ```
     #[must_use]
     fn reinterpret_into<H>(self) -> Vec<H>
     where
         H: crate::private::SealedHalf;
 }

 mod private {
     use crate::{bf16, f16};
     #[cfg(feature = "alloc")]
     #[allow(unused_imports)]
     use alloc::vec::Vec;

     pub trait SealedHalfFloatVec {}
     impl SealedHalfFloatVec for Vec<f16> {}
     impl SealedHalfFloatVec for Vec<bf16> {}

     pub trait SealedHalfBitsVec {}
     impl SealedHalfBitsVec for Vec<u16> {}
 }

 impl HalfFloatVecExt for Vec<f16> {
     #[inline]
     fn reinterpret_into(mut self) -> Vec<u16> {
         // An f16 array has same length and capacity as u16 array
         let length = self.len();
         let capacity = self.capacity();

         // Actually reinterpret the contents of the Vec<f16> as u16,
         // knowing that structs are represented as only their members in memory,
         // which is the u16 part of `f16(u16)`
         let pointer = self.as_mut_ptr() as *mut u16;

         // Prevent running a destructor on the old Vec<u16>, so the pointer won't be deleted
         mem::forget(self);

         // Finally construct a new Vec<f16> from the raw pointer
         // SAFETY: We are reconstructing full length and capacity of original vector,
         // using its original pointer, and the size of elements are identical.
         unsafe { Vec::from_raw_parts(pointer, length, capacity) }
     }

     #[allow(clippy::uninit_vec)]
     fn from_f32_slice(slice: &[f32]) -> Self {
         let mut vec = vec![f16::from_bits(0); slice.len()];
         vec.convert_from_f32_slice(slice);
         vec
     }

     #[allow(clippy::uninit_vec)]
     fn from_f64_slice(slice: &[f64]) -> Self {
         let mut vec = vec![f16::from_bits(0); slice.len()];
         vec.convert_from_f64_slice(slice);
         vec
     }
 }

 impl HalfFloatVecExt for Vec<bf16> {
     #[inline]
     fn reinterpret_into(mut self) -> Vec<u16> {
         // An f16 array has same length and capacity as u16 array
         let length = self.len();
         let capacity = self.capacity();

         // Actually reinterpret the contents of the Vec<f16> as u16,
         // knowing that structs are represented as only their members in memory,
         // which is the u16 part of `f16(u16)`
         let pointer = self.as_mut_ptr() as *mut u16;

         // Prevent running a destructor on the old Vec<u16>, so the pointer won't be deleted
         mem::forget(self);

         // Finally construct a new Vec<f16> from the raw pointer
         // SAFETY: We are reconstructing full length and capacity of original vector,
         // using its original pointer, and the size of elements are identical.
         unsafe { Vec::from_raw_parts(pointer, length, capacity) }
     }

     #[allow(clippy::uninit_vec)]
     fn from_f32_slice(slice: &[f32]) -> Self {
         let mut vec = vec![bf16::from_bits(0); slice.len()];
         vec.convert_from_f32_slice(slice);
         vec
     }

     #[allow(clippy::uninit_vec)]
     fn from_f64_slice(slice: &[f64]) -> Self {
         let mut vec = vec![bf16::from_bits(0); slice.len()];
         vec.convert_from_f64_slice(slice);
         vec
     }
 }

 impl HalfBitsVecExt for Vec<u16> {
     // This is safe because all traits are sealed
     #[inline]
     fn reinterpret_into<H>(mut self) -> Vec<H>
     where
         H: crate::private::SealedHalf,
     {
         // An f16 array has same length and capacity as u16 array
         let length = self.len();
         let capacity = self.capacity();

         // Actually reinterpret the contents of the Vec<u16> as f16,
         // knowing that structs are represented as only their members in memory,
         // which is the u16 part of `f16(u16)`
         let pointer = self.as_mut_ptr() as *mut H;

         // Prevent running a destructor on the old Vec<u16>, so the pointer won't be deleted
         mem::forget(self);

         // Finally construct a new Vec<f16> from the raw pointer
         // SAFETY: We are reconstructing full length and capacity of original vector,
         // using its original pointer, and the size of elements are identical.
         unsafe { Vec::from_raw_parts(pointer, length, capacity) }
     }
 }

 #[cfg(test)]
 mod test {
     use super::{HalfBitsVecExt, HalfFloatVecExt};
     use crate::{bf16, f16};
     #[cfg(all(feature = "alloc", not(feature = "std")))]
     use alloc::vec;

     #[test]
     fn test_vec_conversions_f16() {
         let numbers = vec![f16::E, f16::PI, f16::EPSILON, f16::FRAC_1_SQRT_2];
         let bits = vec![
             f16::E.to_bits(),
             f16::PI.to_bits(),
             f16::EPSILON.to_bits(),
             f16::FRAC_1_SQRT_2.to_bits(),
         ];
         let bits_cloned = bits.clone();

         // Convert from bits to numbers
         let from_bits = bits.reinterpret_into::<f16>();
         assert_eq!(&from_bits[..], &numbers[..]);

         // Convert from numbers back to bits
         let to_bits = from_bits.reinterpret_into();
         assert_eq!(&to_bits[..], &bits_cloned[..]);
     }

     #[test]
     fn test_vec_conversions_bf16() {
         let numbers = vec![bf16::E, bf16::PI, bf16::EPSILON, bf16::FRAC_1_SQRT_2];
         let bits = vec![
             bf16::E.to_bits(),
             bf16::PI.to_bits(),
             bf16::EPSILON.to_bits(),
             bf16::FRAC_1_SQRT_2.to_bits(),
         ];
         let bits_cloned = bits.clone();

         // Convert from bits to numbers
         let from_bits = bits.reinterpret_into::<bf16>();
         assert_eq!(&from_bits[..], &numbers[..]);

         // Convert from numbers back to bits
         let to_bits = from_bits.reinterpret_into();
         assert_eq!(&to_bits[..], &bits_cloned[..]);
     }
 }
	//! Contains utility functions and traits to convert between vectors of [`u16`] bits and [`f16`] or
	//! [`bf16`] vectors.
	//!
	//! The utility [`HalfBitsVecExt`] sealed extension trait is implemented for [`Vec<u16>`] vectors,
	//! while the utility [`HalfFloatVecExt`] sealed extension trait is implemented for both
	//! [`Vec<f16>`] and [`Vec<bf16>`] vectors. These traits provide efficient conversions and
	//! reinterpret casting of larger buffers of floating point values, and are automatically included
	//! in the [`prelude`][crate::prelude] module.
	//!
	//! This module is only available with the `std` or `alloc` feature.

	use super::{bf16, f16, slice::HalfFloatSliceExt};
	#[cfg(feature = "alloc")]
	#[allow(unused_imports)]
	use alloc::vec::Vec;
	use core::mem;

	/// Extensions to [`Vec<f16>`] and [`Vec<bf16>`] to support reinterpret operations.
	///
	/// This trait is sealed and cannot be implemented outside of this crate.
	pub trait HalfFloatVecExt: private::SealedHalfFloatVec {
	/// Reinterprets a vector of [`f16`]or [`bf16`] numbers as a vector of [`u16`] bits.
	///
	/// This is a zero-copy operation. The reinterpreted vector has the same memory location as
	/// `self`.
	///
	/// # Examples
	///
	/// ```rust
	/// # use half::prelude::*;
	/// let float_buffer = vec![f16::from_f32(1.), f16::from_f32(2.), f16::from_f32(3.)];
	/// let int_buffer = float_buffer.reinterpret_into();
	///
	/// assert_eq!(int_buffer, [f16::from_f32(1.).to_bits(), f16::from_f32(2.).to_bits(), f16::from_f32(3.).to_bits()]);
	/// ```
	#[must_use]
	fn reinterpret_into(self) -> Vec<u16>;

	/// Converts all of the elements of a `[f32]` slice into a new [`f16`] or [`bf16`] vector.
	///
	/// The conversion operation is vectorized over the slice, meaning the conversion may be more
	/// efficient than converting individual elements on some hardware that supports SIMD
	/// conversions. See [crate documentation][crate] for more information on hardware conversion
	/// support.
	///
	/// # Examples
	/// ```rust
	/// # use half::prelude::*;
	/// let float_values = [1., 2., 3., 4.];
	/// let vec: Vec<f16> = Vec::from_f32_slice(&float_values);
	///
	/// assert_eq!(vec, vec![f16::from_f32(1.), f16::from_f32(2.), f16::from_f32(3.), f16::from_f32(4.)]);
	/// ```
	#[must_use]
	fn from_f32_slice(slice: &[f32]) -> Self;

	/// Converts all of the elements of a `[f64]` slice into a new [`f16`] or [`bf16`] vector.
	///
	/// The conversion operation is vectorized over the slice, meaning the conversion may be more
	/// efficient than converting individual elements on some hardware that supports SIMD
	/// conversions. See [crate documentation][crate] for more information on hardware conversion
	/// support.
	///
	/// # Examples
	/// ```rust
	/// # use half::prelude::*;
	/// let float_values = [1., 2., 3., 4.];
	/// let vec: Vec<f16> = Vec::from_f64_slice(&float_values);
	///
	/// assert_eq!(vec, vec![f16::from_f64(1.), f16::from_f64(2.), f16::from_f64(3.), f16::from_f64(4.)]);
	/// ```
	#[must_use]
	fn from_f64_slice(slice: &[f64]) -> Self;
	}

	/// Extensions to [`Vec<u16>`] to support reinterpret operations.
	///
	/// This trait is sealed and cannot be implemented outside of this crate.
	pub trait HalfBitsVecExt: private::SealedHalfBitsVec {
	/// Reinterprets a vector of [`u16`] bits as a vector of [`f16`] or [`bf16`] numbers.
	///
	/// `H` is the type to cast to, and must be either the [`f16`] or [`bf16`] type.
	///
	/// This is a zero-copy operation. The reinterpreted vector has the same memory location as
	/// `self`.
	///
	/// # Examples
	///
	/// ```rust
	/// # use half::prelude::*;
	/// let int_buffer = vec![f16::from_f32(1.).to_bits(), f16::from_f32(2.).to_bits(), f16::from_f32(3.).to_bits()];
	/// let float_buffer = int_buffer.reinterpret_into::<f16>();
	///
	/// assert_eq!(float_buffer, [f16::from_f32(1.), f16::from_f32(2.), f16::from_f32(3.)]);
	/// ```
	#[must_use]
	fn reinterpret_into<H>(self) -> Vec<H>
	where
	H: crate::private::SealedHalf;
	}

	mod private {
	use crate::{bf16, f16};
	#[cfg(feature = "alloc")]
	#[allow(unused_imports)]
	use alloc::vec::Vec;

	pub trait SealedHalfFloatVec {}
	impl SealedHalfFloatVec for Vec<f16> {}
	impl SealedHalfFloatVec for Vec<bf16> {}

	pub trait SealedHalfBitsVec {}
	impl SealedHalfBitsVec for Vec<u16> {}
	}

	impl HalfFloatVecExt for Vec<f16> {
	#[inline]
	fn reinterpret_into(mut self) -> Vec<u16> {
	// An f16 array has same length and capacity as u16 array
	let length = self.len();
	let capacity = self.capacity();

	// Actually reinterpret the contents of the Vec<f16> as u16,
	// knowing that structs are represented as only their members in memory,
	// which is the u16 part of `f16(u16)`
	let pointer = self.as_mut_ptr() as *mut u16;

	// Prevent running a destructor on the old Vec<u16>, so the pointer won't be deleted
	mem::forget(self);

	// Finally construct a new Vec<f16> from the raw pointer
	// SAFETY: We are reconstructing full length and capacity of original vector,
	// using its original pointer, and the size of elements are identical.
	unsafe { Vec::from_raw_parts(pointer, length, capacity) }
	}

	#[allow(clippy::uninit_vec)]
	fn from_f32_slice(slice: &[f32]) -> Self {
	let mut vec = vec![f16::from_bits(0); slice.len()];
	vec.convert_from_f32_slice(slice);
	vec
	}

	#[allow(clippy::uninit_vec)]
	fn from_f64_slice(slice: &[f64]) -> Self {
	let mut vec = vec![f16::from_bits(0); slice.len()];
	vec.convert_from_f64_slice(slice);
	vec
	}
	}

	impl HalfFloatVecExt for Vec<bf16> {
	#[inline]
	fn reinterpret_into(mut self) -> Vec<u16> {
	// An f16 array has same length and capacity as u16 array
	let length = self.len();
	let capacity = self.capacity();

	// Actually reinterpret the contents of the Vec<f16> as u16,
	// knowing that structs are represented as only their members in memory,
	// which is the u16 part of `f16(u16)`
	let pointer = self.as_mut_ptr() as *mut u16;

	// Prevent running a destructor on the old Vec<u16>, so the pointer won't be deleted
	mem::forget(self);

	// Finally construct a new Vec<f16> from the raw pointer
	// SAFETY: We are reconstructing full length and capacity of original vector,
	// using its original pointer, and the size of elements are identical.
	unsafe { Vec::from_raw_parts(pointer, length, capacity) }
	}

	#[allow(clippy::uninit_vec)]
	fn from_f32_slice(slice: &[f32]) -> Self {
	let mut vec = vec![bf16::from_bits(0); slice.len()];
	vec.convert_from_f32_slice(slice);
	vec
	}

	#[allow(clippy::uninit_vec)]
	fn from_f64_slice(slice: &[f64]) -> Self {
	let mut vec = vec![bf16::from_bits(0); slice.len()];
	vec.convert_from_f64_slice(slice);
	vec
	}
	}

	impl HalfBitsVecExt for Vec<u16> {
	// This is safe because all traits are sealed
	#[inline]
	fn reinterpret_into<H>(mut self) -> Vec<H>
	where
	H: crate::private::SealedHalf,
	{
	// An f16 array has same length and capacity as u16 array
	let length = self.len();
	let capacity = self.capacity();

	// Actually reinterpret the contents of the Vec<u16> as f16,
	// knowing that structs are represented as only their members in memory,
	// which is the u16 part of `f16(u16)`
	let pointer = self.as_mut_ptr() as *mut H;

	// Prevent running a destructor on the old Vec<u16>, so the pointer won't be deleted
	mem::forget(self);

	// Finally construct a new Vec<f16> from the raw pointer
	// SAFETY: We are reconstructing full length and capacity of original vector,
	// using its original pointer, and the size of elements are identical.
	unsafe { Vec::from_raw_parts(pointer, length, capacity) }
	}
	}

	#[cfg(test)]
	mod test {
	use super::{HalfBitsVecExt, HalfFloatVecExt};
	use crate::{bf16, f16};
	#[cfg(all(feature = "alloc", not(feature = "std")))]
	use alloc::vec;

	#[test]
	fn test_vec_conversions_f16() {
	let numbers = vec![f16::E, f16::PI, f16::EPSILON, f16::FRAC_1_SQRT_2];
	let bits = vec![
	f16::E.to_bits(),
	f16::PI.to_bits(),
	f16::EPSILON.to_bits(),
	f16::FRAC_1_SQRT_2.to_bits(),
	];
	let bits_cloned = bits.clone();

	// Convert from bits to numbers
	let from_bits = bits.reinterpret_into::<f16>();
	assert_eq!(&from_bits[..], &numbers[..]);

	// Convert from numbers back to bits
	let to_bits = from_bits.reinterpret_into();
	assert_eq!(&to_bits[..], &bits_cloned[..]);
	}

	#[test]
	fn test_vec_conversions_bf16() {
	let numbers = vec![bf16::E, bf16::PI, bf16::EPSILON, bf16::FRAC_1_SQRT_2];
	let bits = vec![
	bf16::E.to_bits(),
	bf16::PI.to_bits(),
	bf16::EPSILON.to_bits(),
	bf16::FRAC_1_SQRT_2.to_bits(),
	];
	let bits_cloned = bits.clone();

	// Convert from bits to numbers
	let from_bits = bits.reinterpret_into::<bf16>();
	assert_eq!(&from_bits[..], &numbers[..]);

	// Convert from numbers back to bits
	let to_bits = from_bits.reinterpret_into();
	assert_eq!(&to_bits[..], &bits_cloned[..]);
	}
	}