nalgebra/base/construction_view.rs
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use crate::base::dimension::{Const, Dim, DimName, Dyn};
use crate::base::matrix_view::{ViewStorage, ViewStorageMut};
use crate::base::{MatrixView, MatrixViewMut, Scalar};
use num_rational::Ratio;
/// # Creating matrix views from `&[T]`
impl<'a, T: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
MatrixView<'a, T, R, C, RStride, CStride>
{
/// Creates, without bounds checking, a matrix view from an array and with dimensions and strides specified by generic types instances.
///
/// # Safety
/// This method is unsafe because the input data array is not checked to contain enough elements.
/// The generic types `R`, `C`, `RStride`, `CStride` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub unsafe fn from_slice_with_strides_generic_unchecked(
data: &'a [T],
start: usize,
nrows: R,
ncols: C,
rstride: RStride,
cstride: CStride,
) -> Self {
let data = ViewStorage::from_raw_parts(
data.as_ptr().add(start),
(nrows, ncols),
(rstride, cstride),
);
Self::from_data(data)
}
/// Creates a matrix view from an array and with dimensions and strides specified by generic types instances.
///
/// Panics if the input data array dose not contain enough elements.
/// The generic types `R`, `C`, `RStride`, `CStride` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub fn from_slice_with_strides_generic(
data: &'a [T],
nrows: R,
ncols: C,
rstride: RStride,
cstride: CStride,
) -> Self {
// NOTE: The assertion implements the following formula, but without subtractions to avoid
// underflow panics:
// len >= (ncols - 1) * cstride + (nrows - 1) * rstride + 1
assert!(
data.len() + cstride.value() + rstride.value()
>= ncols.value() * cstride.value() + nrows.value() * rstride.value() + 1,
"Matrix view: input data buffer too small."
);
unsafe {
Self::from_slice_with_strides_generic_unchecked(data, 0, nrows, ncols, rstride, cstride)
}
}
}
impl<'a, T: Scalar, R: Dim, C: Dim> MatrixView<'a, T, R, C> {
/// Creates, without bound-checking, a matrix view from an array and with dimensions specified by generic types instances.
///
/// # Safety
/// This method is unsafe because the input data array is not checked to contain enough elements.
/// The generic types `R` and `C` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub unsafe fn from_slice_generic_unchecked(
data: &'a [T],
start: usize,
nrows: R,
ncols: C,
) -> Self {
Self::from_slice_with_strides_generic_unchecked(
data, start, nrows, ncols, Const::<1>, nrows,
)
}
/// Creates a matrix view from an array and with dimensions and strides specified by generic types instances.
///
/// Panics if the input data array dose not contain enough elements.
/// The generic types `R` and `C` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub fn from_slice_generic(data: &'a [T], nrows: R, ncols: C) -> Self {
Self::from_slice_with_strides_generic(data, nrows, ncols, Const::<1>, nrows)
}
}
macro_rules! impl_constructors(
($($Dims: ty),*; $(=> $DimIdent: ident: $DimBound: ident),*; $($gargs: expr),*; $($args: ident),*) => {
impl<'a, T: Scalar, $($DimIdent: $DimBound),*> MatrixView<'a, T, $($Dims),*> {
/// Creates a new matrix view from the given data array.
///
/// Panics if `data` does not contain enough elements.
#[inline]
pub fn from_slice(data: &'a [T], $($args: usize),*) -> Self {
Self::from_slice_generic(data, $($gargs),*)
}
/// Creates, without bound checking, a new matrix view from the given data array.
/// # Safety
/// `data[start..start+rstride * cstride]` must be within bounds.
#[inline]
pub unsafe fn from_slice_unchecked(data: &'a [T], start: usize, $($args: usize),*) -> Self {
Self::from_slice_generic_unchecked(data, start, $($gargs),*)
}
}
impl<'a, T: Scalar, $($DimIdent: $DimBound, )*> MatrixView<'a, T, $($Dims,)* Dyn, Dyn> {
/// Creates a new matrix view with the specified strides from the given data array.
///
/// Panics if `data` does not contain enough elements.
#[inline]
pub fn from_slice_with_strides(data: &'a [T], $($args: usize,)* rstride: usize, cstride: usize) -> Self {
Self::from_slice_with_strides_generic(data, $($gargs,)* Dyn(rstride), Dyn(cstride))
}
/// Creates, without bound checking, a new matrix view with the specified strides from the given data array.
///
/// # Safety
///
/// `start`, `rstride`, and `cstride`, with the given matrix size will not index
/// outside of `data`.
#[inline]
pub unsafe fn from_slice_with_strides_unchecked(data: &'a [T], start: usize, $($args: usize,)* rstride: usize, cstride: usize) -> Self {
Self::from_slice_with_strides_generic_unchecked(data, start, $($gargs,)* Dyn(rstride), Dyn(cstride))
}
}
}
);
// TODO: this is not very pretty. We could find a better call syntax.
impl_constructors!(R, C; // Arguments for Matrix<T, ..., S>
=> R: DimName, => C: DimName; // Type parameters for impl<T, ..., S>
R::name(), C::name(); // Arguments for `_generic` constructors.
); // Arguments for non-generic constructors.
impl_constructors!(R, Dyn;
=> R: DimName;
R::name(), Dyn(ncols);
ncols);
impl_constructors!(Dyn, C;
=> C: DimName;
Dyn(nrows), C::name();
nrows);
impl_constructors!(Dyn, Dyn;
;
Dyn(nrows), Dyn(ncols);
nrows, ncols);
/// # Creating mutable matrix views from `&mut [T]`
impl<'a, T: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim>
MatrixViewMut<'a, T, R, C, RStride, CStride>
{
/// Creates, without bound-checking, a mutable matrix view from an array and with dimensions and strides specified by generic types instances.
///
/// # Safety
/// This method is unsafe because the input data array is not checked to contain enough elements.
/// The generic types `R`, `C`, `RStride`, `CStride` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub unsafe fn from_slice_with_strides_generic_unchecked(
data: &'a mut [T],
start: usize,
nrows: R,
ncols: C,
rstride: RStride,
cstride: CStride,
) -> Self {
let data = ViewStorageMut::from_raw_parts(
data.as_mut_ptr().add(start),
(nrows, ncols),
(rstride, cstride),
);
Self::from_data(data)
}
/// Creates a mutable matrix view from an array and with dimensions and strides specified by generic types instances.
///
/// Panics if the input data array dose not contain enough elements.
/// The generic types `R`, `C`, `RStride`, `CStride` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub fn from_slice_with_strides_generic(
data: &'a mut [T],
nrows: R,
ncols: C,
rstride: RStride,
cstride: CStride,
) -> Self {
// NOTE: The assertion implements the following formula, but without subtractions to avoid
// underflow panics:
// len >= (ncols - 1) * cstride + (nrows - 1) * rstride + 1
assert!(
data.len() + cstride.value() + rstride.value()
>= ncols.value() * cstride.value() + nrows.value() * rstride.value() + 1,
"Matrix view: input data buffer too small."
);
assert!(
{
let nrows = nrows.value();
let ncols = ncols.value();
let rstride = rstride.value();
let cstride = cstride.value();
nrows * ncols <= 1
|| match (rstride, cstride) {
(0, 0) => false, // otherwise: matrix[(0, 0)] == index[(nrows - 1, ncols - 1)],
(0, _) => nrows <= 1, // otherwise: matrix[(0, 0)] == index[(nrows - 1, 0)],
(_, 0) => ncols <= 1, // otherwise: matrix[(0, 0)] == index[(0, ncols - 1)],
(_, _) => {
// otherwise: matrix[(0, numer)] == index[(denom, 0)]
let ratio = Ratio::new(rstride, cstride);
nrows <= *ratio.denom() || ncols <= *ratio.numer()
}
}
},
"Matrix view: dimensions and strides result in aliased indices."
);
unsafe {
Self::from_slice_with_strides_generic_unchecked(data, 0, nrows, ncols, rstride, cstride)
}
}
}
impl<'a, T: Scalar, R: Dim, C: Dim> MatrixViewMut<'a, T, R, C> {
/// Creates, without bound-checking, a mutable matrix view from an array and with dimensions specified by generic types instances.
///
/// # Safety
/// This method is unsafe because the input data array is not checked to contain enough elements.
/// The generic types `R` and `C` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub unsafe fn from_slice_generic_unchecked(
data: &'a mut [T],
start: usize,
nrows: R,
ncols: C,
) -> Self {
Self::from_slice_with_strides_generic_unchecked(
data, start, nrows, ncols, Const::<1>, nrows,
)
}
/// Creates a mutable matrix view from an array and with dimensions and strides specified by generic types instances.
///
/// Panics if the input data array dose not contain enough elements.
/// The generic types `R` and `C` can either be type-level integers or integers wrapped with `Dyn()`.
#[inline]
pub fn from_slice_generic(data: &'a mut [T], nrows: R, ncols: C) -> Self {
Self::from_slice_with_strides_generic(data, nrows, ncols, Const::<1>, nrows)
}
}
macro_rules! impl_constructors_mut(
($($Dims: ty),*; $(=> $DimIdent: ident: $DimBound: ident),*; $($gargs: expr),*; $($args: ident),*) => {
impl<'a, T: Scalar, $($DimIdent: $DimBound),*> MatrixViewMut<'a, T, $($Dims),*> {
/// Creates a new mutable matrix view from the given data array.
///
/// Panics if `data` does not contain enough elements.
#[inline]
pub fn from_slice(data: &'a mut [T], $($args: usize),*) -> Self {
Self::from_slice_generic(data, $($gargs),*)
}
/// Creates, without bound checking, a new mutable matrix view from the given data array.
///
/// # Safety
///
/// `data[start..start+(R * C)]` must be within bounds.
#[inline]
pub unsafe fn from_slice_unchecked(data: &'a mut [T], start: usize, $($args: usize),*) -> Self {
Self::from_slice_generic_unchecked(data, start, $($gargs),*)
}
}
impl<'a, T: Scalar, $($DimIdent: $DimBound, )*> MatrixViewMut<'a, T, $($Dims,)* Dyn, Dyn> {
/// Creates a new mutable matrix view with the specified strides from the given data array.
///
/// Panics if `data` does not contain enough elements.
#[inline]
pub fn from_slice_with_strides_mut(data: &'a mut [T], $($args: usize,)* rstride: usize, cstride: usize) -> Self {
Self::from_slice_with_strides_generic(
data, $($gargs,)* Dyn(rstride), Dyn(cstride))
}
/// Creates, without bound checking, a new mutable matrix view with the specified strides from the given data array.
/// # Safety
/// `data[start..start+rstride * cstride]` must be within bounds.
#[inline]
pub unsafe fn from_slice_with_strides_unchecked(data: &'a mut [T], start: usize, $($args: usize,)* rstride: usize, cstride: usize) -> Self {
Self::from_slice_with_strides_generic_unchecked(
data, start, $($gargs,)* Dyn(rstride), Dyn(cstride))
}
}
}
);
// TODO: this is not very pretty. We could find a better call syntax.
impl_constructors_mut!(R, C; // Arguments for Matrix<T, ..., S>
=> R: DimName, => C: DimName; // Type parameters for impl<T, ..., S>
R::name(), C::name(); // Arguments for `_generic` constructors.
); // Arguments for non-generic constructors.
impl_constructors_mut!(R, Dyn;
=> R: DimName;
R::name(), Dyn(ncols);
ncols);
impl_constructors_mut!(Dyn, C;
=> C: DimName;
Dyn(nrows), C::name();
nrows);
impl_constructors_mut!(Dyn, Dyn;
;
Dyn(nrows), Dyn(ncols);
nrows, ncols);