Add unsafe slice construction.

src/core/construction_slice.rs

@@ -23,6 +23,15 @@ use core::matrix_slice::{SliceStorage, SliceStorageMut};
  *
  */
 impl<'a, N: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim> MatrixSliceMN<'a, N, R, C, RStride, CStride> {
+    #[inline]
+    pub unsafe fn new_slice_with_strides_generic_unchecked(
+        data: &'a [N], start: usize, nrows: R, ncols: C, rstride: RStride, cstride: CStride) -> Self {
+        let data = unsafe {
+            SliceStorage::from_raw_parts(data.as_ptr().offset(start as isize), (nrows, ncols), (rstride, cstride))
+        };
+        Self::from_data(data)
+    }
+
     #[inline]
     pub fn new_slice_with_strides_generic(data: &'a [N], nrows: R, ncols: C, rstride: RStride, cstride: CStride) -> Self {
         // NOTE: The assertion implements the following formula, but without subtractions to avoid
@@ -32,14 +41,22 @@ impl<'a, N: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim> MatrixSliceMN<'a
                 ncols.value() * cstride.value() + nrows.value() * rstride.value() + 1,
                 "Matrix slice: input data buffer to small.");
 
-        let data = unsafe {
-            SliceStorage::from_raw_parts(data.as_ptr(), (nrows, ncols), (rstride, cstride))
-        };
-        Self::from_data(data)
+        unsafe {
+            Self::new_slice_with_strides_generic_unchecked(data, 0, nrows, ncols, rstride, cstride)
+        }
     }
 }
 
 impl<'a, N: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim> MatrixSliceMutMN<'a, N, R, C, RStride, CStride> {
+    #[inline]
+    pub unsafe fn new_slice_with_strides_mut_generic_unchecked(
+        data: &'a mut [N], start: usize, nrows: R, ncols: C, rstride: RStride, cstride: CStride) -> Self {
+        let data = unsafe {
+            SliceStorageMut::from_raw_parts(data.as_mut_ptr().offset(start as isize), (nrows, ncols), (rstride, cstride))
+        };
+        Self::from_data(data)
+    }
+
     #[inline]
     pub fn new_slice_with_strides_mut_generic(data: &'a mut [N], nrows: R, ncols: C, rstride: RStride, cstride: CStride) -> Self {
         // NOTE: The assertion implements the following formula, but without subtractions to avoid
@@ -49,14 +66,18 @@ impl<'a, N: Scalar, R: Dim, C: Dim, RStride: Dim, CStride: Dim> MatrixSliceMutMN
                 ncols.value() * cstride.value() + nrows.value() * rstride.value() + 1,
                 "Matrix slice: input data buffer to small.");
 
-        let data = unsafe {
-            SliceStorageMut::from_raw_parts(data.as_mut_ptr(), (nrows, ncols), (rstride, cstride))
-        };
-        Self::from_data(data)
+        unsafe {
+            Self::new_slice_with_strides_mut_generic_unchecked(data, 0, nrows, ncols, rstride, cstride)
+        }
     }
 }
 
 impl<'a, N: Scalar, R: Dim, C: Dim> MatrixSliceMN<'a, N, R, C> {
+    #[inline]
+    pub unsafe fn new_slice_generic_unchecked(data: &'a [N], start: usize, nrows: R, ncols: C) -> Self {
+        Self::new_slice_with_strides_generic_unchecked(data, start, nrows, ncols, U1, nrows)
+    }
+
     #[inline]
     pub fn new_slice_generic(data: &'a [N], nrows: R, ncols: C) -> Self {
         Self::new_slice_with_strides_generic(data, nrows, ncols, U1, nrows)
@@ -64,6 +85,11 @@ impl<'a, N: Scalar, R: Dim, C: Dim> MatrixSliceMN<'a, N, R, C> {
 }
 
 impl<'a, N: Scalar, R: Dim, C: Dim> MatrixSliceMutMN<'a, N, R, C> {
+    #[inline]
+    pub unsafe fn new_slice_mut_generic_unchecked(data: &'a mut [N], start: usize, nrows: R, ncols: C) -> Self {
+        Self::new_slice_with_strides_mut_generic_unchecked(data, start, nrows, ncols, U1, nrows)
+    }
+
     #[inline]
     pub fn new_slice_mut_generic(data: &'a mut [N], nrows: R, ncols: C) -> Self {
         Self::new_slice_with_strides_mut_generic(data, nrows, ncols, U1, nrows)
@@ -77,6 +103,11 @@ macro_rules! impl_constructors(
             pub fn new(data: &'a [N], $($args: usize),*) -> Self {
                 Self::new_slice_generic(data, $($gargs),*)
             }
+
+            #[inline]
+            pub unsafe fn new_unchecked(data: &'a [N], start: usize, $($args: usize),*) -> Self {
+                Self::new_slice_generic_unchecked(data, start, $($gargs),*)
+            }
         }
 
         impl<'a, N: Scalar, $($DimIdent: $DimBound, )*> MatrixSliceMN<'a, N, $($Dims,)* Dynamic, Dynamic> {
@@ -84,6 +115,11 @@ macro_rules! impl_constructors(
             pub fn new_with_strides(data: &'a [N], $($args: usize,)* rstride: usize, cstride: usize) -> Self {
                 Self::new_slice_with_strides_generic(data, $($gargs,)* Dynamic::new(rstride), Dynamic::new(cstride))
             }
+
+            #[inline]
+            pub unsafe fn new_with_strides_unchecked(data: &'a [N], start: usize, $($args: usize,)* rstride: usize, cstride: usize) -> Self {
+                Self::new_slice_with_strides_generic_unchecked(data, start, $($gargs,)* Dynamic::new(rstride), Dynamic::new(cstride))
+            }
         }
     }
 );
@@ -118,6 +154,11 @@ macro_rules! impl_constructors_mut(
             pub fn new(data: &'a mut [N], $($args: usize),*) -> Self {
                 Self::new_slice_mut_generic(data, $($gargs),*)
             }
+
+            #[inline]
+            pub unsafe fn new_unchecked(data: &'a mut [N], start: usize, $($args: usize),*) -> Self {
+                Self::new_slice_mut_generic_unchecked(data, start, $($gargs),*)
+            }
         }
 
         impl<'a, N: Scalar, $($DimIdent: $DimBound, )*> MatrixSliceMutMN<'a, N, $($Dims,)* Dynamic, Dynamic> {
@@ -126,6 +167,12 @@ macro_rules! impl_constructors_mut(
                 Self::new_slice_with_strides_mut_generic(
                     data, $($gargs,)* Dynamic::new(rstride), Dynamic::new(cstride))
             }
+
+            #[inline]
+            pub unsafe fn new_with_strides_unchecked(data: &'a mut [N], start: usize, $($args: usize,)* rstride: usize, cstride: usize) -> Self {
+                Self::new_slice_with_strides_mut_generic_unchecked(
+                    data, start, $($gargs,)* Dynamic::new(rstride), Dynamic::new(cstride))
+            }
         }
     }
 );