Merge pull request #662 from Aaron1011/fix/final-offset

Don't call 'offset' on a dangling pointer

src/base/iter.rs

@@ -27,12 +27,30 @@ macro_rules! iterator {
                 let shape = storage.shape();
                 let strides = storage.strides();
                 let inner_offset = shape.0.value() * strides.0.value();
+                let size = shape.0.value() * shape.1.value();
                 let ptr = storage.$ptr();
 
+                // If we have a size of 0, 'ptr' must be
+                // dangling. Howver, 'inner_offset' might
+                // not be zero if only one dimension is zero, so
+                // we don't want to call 'offset'.
+                // This pointer will never actually get used
+                // if our size is '0', so it's fine to use
+                // 'ptr' for both the start and end.
+                let inner_end = if size == 0 {
+                    ptr
+                } else {
+                    // Safety:
+                    // If 'size' is non-zero, we know that 'ptr'
+                    // is not dangling, and 'inner_offset' must lie
+                    // within the allocation
+                    unsafe { ptr.offset(inner_offset as isize) }
+                };
+
                 $Name {
                     ptr: ptr,
                     inner_ptr: ptr,
-                    inner_end: unsafe { ptr.offset(inner_offset as isize) },
+                    inner_end,
                     size: shape.0.value() * shape.1.value(),
                     strides: strides,
                     _phantoms: PhantomData,

src/base/storage.rs

@@ -72,7 +72,7 @@ pub unsafe trait Storage<N: Scalar, R: Dim, C: Dim = U1>: Debug + Sized {
     /// Gets the address of the i-th matrix component without performing bound-checking.
     #[inline]
     unsafe fn get_address_unchecked_linear(&self, i: usize) -> *const N {
-        self.ptr().offset(i as isize)
+        self.ptr().wrapping_offset(i as isize)
     }
 
     /// Gets the address of the i-th matrix component without performing bound-checking.
@@ -124,7 +124,7 @@ pub unsafe trait StorageMut<N: Scalar, R: Dim, C: Dim = U1>: Storage<N, R, C> {
     /// Gets the mutable address of the i-th matrix component without performing bound-checking.
     #[inline]
     unsafe fn get_address_unchecked_linear_mut(&mut self, i: usize) -> *mut N {
-        self.ptr_mut().offset(i as isize)
+        self.ptr_mut().wrapping_offset(i as isize)
     }
 
     /// Gets the mutable address of the i-th matrix component without performing bound-checking.