Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 286 insertions, 0 deletions

diff --git a/third_party/rust/half/src/vec.rs b/third_party/rust/half/src/vec.rs
new file mode 100644
index 0000000000..6967656e4d
--- /dev/null
+++ b/third_party/rust/half/src/vec.rs
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+//! 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")]
+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()]);
+    /// ```
+    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.)]);
+    /// ```
+    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.)]);
+    /// ```
+    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.)]);
+    /// ```
+    fn reinterpret_into<H>(self) -> Vec<H>
+    where
+        H: crate::private::SealedHalf;
+}
+
+mod private {
+    use crate::{bf16, f16};
+    #[cfg(feature = "alloc")]
+    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) }
+    }
+
+    fn from_f32_slice(slice: &[f32]) -> Self {
+        let mut vec = Vec::with_capacity(slice.len());
+        // SAFETY: convert will initialize every value in the vector without reading them,
+        // so this is safe to do instead of double initialize from resize, and we're setting it to
+        // same value as capacity.
+        unsafe { vec.set_len(slice.len()) };
+        vec.convert_from_f32_slice(slice);
+        vec
+    }
+
+    fn from_f64_slice(slice: &[f64]) -> Self {
+        let mut vec = Vec::with_capacity(slice.len());
+        // SAFETY: convert will initialize every value in the vector without reading them,
+        // so this is safe to do instead of double initialize from resize, and we're setting it to
+        // same value as capacity.
+        unsafe { vec.set_len(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) }
+    }
+
+    fn from_f32_slice(slice: &[f32]) -> Self {
+        let mut vec = Vec::with_capacity(slice.len());
+        // SAFETY: convert will initialize every value in the vector without reading them,
+        // so this is safe to do instead of double initialize from resize, and we're setting it to
+        // same value as capacity.
+        unsafe { vec.set_len(slice.len()) };
+        vec.convert_from_f32_slice(slice);
+        vec
+    }
+
+    fn from_f64_slice(slice: &[f64]) -> Self {
+        let mut vec = Vec::with_capacity(slice.len());
+        // SAFETY: convert will initialize every value in the vector without reading them,
+        // so this is safe to do instead of double initialize from resize, and we're setting it to
+        // same value as capacity.
+        unsafe { vec.set_len(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) }
+    }
+}
+
+#[doc(hidden)]
+#[deprecated(
+    since = "1.4.0",
+    note = "use `HalfBitsVecExt::reinterpret_into` instead"
+)]
+#[inline]
+pub fn from_bits(bits: Vec<u16>) -> Vec<f16> {
+    bits.reinterpret_into()
+}
+
+#[doc(hidden)]
+#[deprecated(
+    since = "1.4.0",
+    note = "use `HalfFloatVecExt::reinterpret_into` instead"
+)]
+#[inline]
+pub fn to_bits(numbers: Vec<f16>) -> Vec<u16> {
+    numbers.reinterpret_into()
+}
+
+#[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[..]);
+    }
+}