Merge pull request #543 from jturner314/clarify-invariants

Clarify invariants and fix constructors and is_standard_layout

Author: jturner314

Cargo.toml

@@ -39,6 +39,7 @@ serde = { version = "1.0", optional = true }
 
 [dev-dependencies]
 defmac = "0.1"
+quickcheck = { version = "0.7.2", default-features = false }
 rawpointer = "0.1"
 
 [features]

src/array_serialize.rs

@@ -8,6 +8,7 @@
 
 use serialize::{Encodable, Encoder, Decodable, Decoder};
 use super::arraytraits::ARRAY_FORMAT_VERSION;
+use super::dimension;
 
 use imp_prelude::*;
 
@@ -74,7 +75,9 @@ impl<A, S, D> Decodable for ArrayBase<S, D>
             let elements = try!(
                 d.read_struct_field("data", 2, |d| {
                     d.read_seq(|d, len| {
-                        if len != dim.size() {
+                        let dim_size = dimension::size_of_shape_checked(&dim)
+                            .map_err(|_| d.error("overflow calculating array size"))?;
+                        if len != dim_size {
                             Err(d.error("data and dimension must match in size"))
                         } else {
                             let mut elements = Vec::with_capacity(len);

src/arraytraits.rs

@@ -9,6 +9,7 @@
 use std::hash;
 use std::iter::FromIterator;
 use std::iter::IntoIterator;
+use std::mem;
 use std::ops::{
     Index,
     IndexMut,
@@ -216,11 +217,19 @@ pub const ARRAY_FORMAT_VERSION: u8 = 1u8;
 /// Implementation of `ArrayView::from(&S)` where `S` is a slice or slicable.
 ///
 /// Create a one-dimensional read-only array view of the data in `slice`.
+///
+/// **Panics** if the slice length is greater than `isize::MAX`.
 impl<'a, A, Slice: ?Sized> From<&'a Slice> for ArrayView<'a, A, Ix1>
     where Slice: AsRef<[A]>
 {
     fn from(slice: &'a Slice) -> Self {
         let xs = slice.as_ref();
+        if mem::size_of::<A>() == 0 {
+            assert!(
+                xs.len() <= ::std::isize::MAX as usize,
+                "Slice length must fit in `isize`.",
+            );
+        }
         unsafe {
             Self::from_shape_ptr(xs.len(), xs.as_ptr())
         }
@@ -242,11 +251,19 @@ impl<'a, A, S, D> From<&'a ArrayBase<S, D>> for ArrayView<'a, A, D>
 /// Implementation of `ArrayViewMut::from(&mut S)` where `S` is a slice or slicable.
 ///
 /// Create a one-dimensional read-write array view of the data in `slice`.
+///
+/// **Panics** if the slice length is greater than `isize::MAX`.
 impl<'a, A, Slice: ?Sized> From<&'a mut Slice> for ArrayViewMut<'a, A, Ix1>
     where Slice: AsMut<[A]>
 {
     fn from(slice: &'a mut Slice) -> Self {
         let xs = slice.as_mut();
+        if mem::size_of::<A>() == 0 {
+            assert!(
+                xs.len() <= ::std::isize::MAX as usize,
+                "Slice length must fit in `isize`.",
+            );
+        }
         unsafe {
             Self::from_shape_ptr(xs.len(), xs.as_mut_ptr())
         }

src/dimension/dimension_trait.rs

@@ -109,12 +109,17 @@ pub trait Dimension : Clone + Eq + Debug + Send + Sync + Default +
         self.slice() == rhs.slice()
     }
 
+    /// Returns the strides for a standard layout array with the given shape.
+    ///
+    /// If the array is non-empty, the strides result in contiguous layout; if
+    /// the array is empty, the strides are all zeros.
     #[doc(hidden)]
     fn default_strides(&self) -> Self {
         // Compute default array strides
         // Shape (a, b, c) => Give strides (b * c, c, 1)
-        let mut strides = self.clone();
-        {
+        let mut strides = Self::zeros(self.ndim());
+        // For empty arrays, use all zero strides.
+        if self.slice().iter().all(|&d| d != 0) {
             let mut it = strides.slice_mut().iter_mut().rev();
             // Set first element to 1
             while let Some(rs) = it.next() {
@@ -130,12 +135,17 @@ pub trait Dimension : Clone + Eq + Debug + Send + Sync + Default +
         strides
     }
 
+    /// Returns the strides for a Fortran layout array with the given shape.
+    ///
+    /// If the array is non-empty, the strides result in contiguous layout; if
+    /// the array is empty, the strides are all zeros.
     #[doc(hidden)]
     fn fortran_strides(&self) -> Self {
         // Compute fortran array strides
         // Shape (a, b, c) => Give strides (1, a, a * b)
-        let mut strides = self.clone();
-        {
+        let mut strides = Self::zeros(self.ndim());
+        // For empty arrays, use all zero strides.
+        if self.slice().iter().all(|&d| d != 0) {
             let mut it = strides.slice_mut().iter_mut();
             // Set first element to 1
             while let Some(rs) = it.next() {
@@ -432,7 +442,11 @@ impl Dimension for Dim<[Ix; 1]> {
 
     #[inline]
     fn default_strides(&self) -> Self {
-        Ix1(1)
+        if get!(self, 0) == 0 {
+            Ix1(0)
+        } else {
+            Ix1(1)
+        }
     }
 
     #[inline]
@@ -548,13 +562,23 @@ impl Dimension for Dim<[Ix; 2]> {
 
     #[inline]
     fn default_strides(&self) -> Self {
-        // Compute default array strides
-        // Shape (a, b, c) => Give strides (b * c, c, 1)
-        Ix2(get!(self, 1), 1)
+        let m = get!(self, 0);
+        let n = get!(self, 1);
+        if m == 0 || n == 0 {
+            Ix2(0, 0)
+        } else {
+            Ix2(n, 1)
+        }
     }
     #[inline]
     fn fortran_strides(&self) -> Self {
-        Ix2(1, get!(self, 0))
+        let m = get!(self, 0);
+        let n = get!(self, 1);
+        if m == 0 || n == 0 {
+            Ix2(0, 0)
+        } else {
+            Ix2(1, m)
+        }
     }
 
     #[inline]