Fix computation of data range of more-than-one-dimensional arrays.

Author: adamreichold

src/borrow.rs

@@ -161,7 +161,7 @@
 
 use std::cell::UnsafeCell;
 use std::collections::hash_map::{Entry, HashMap};
-use std::ops::{Deref, Range};
+use std::ops::Deref;
 
 use ndarray::{ArrayView, ArrayViewMut, Dimension, Ix1, Ix2, Ix3, Ix4, Ix5, Ix6, IxDyn};
 use num_integer::gcd;
@@ -176,8 +176,11 @@ use crate::npyffi::{self, PyArrayObject, NPY_ARRAY_WRITEABLE};
 
 #[derive(PartialEq, Eq, Hash)]
 struct BorrowKey {
-    range: Range<usize>,
+    /// inclusive range of lowest and highest address covered by array
+    range: (usize, usize),
+    /// the data address on which address computations are based
     data_ptr: usize,
+    /// the greatest common divisor of the strides of the array
     gcd_strides: isize,
 }
 
@@ -200,10 +203,10 @@ impl BorrowKey {
     }
 
     fn conflicts(&self, other: &Self) -> bool {
-        debug_assert!(self.range.start <= self.range.end);
-        debug_assert!(other.range.start <= other.range.end);
+        debug_assert!(self.range.0 <= self.range.1);
+        debug_assert!(other.range.0 <= other.range.1);
 
-        if other.range.start >= self.range.end || other.range.end <= self.range.start {
+        if other.range.0 > self.range.1 || self.range.0 > other.range.1 {
             return false;
         }
 
@@ -646,7 +649,7 @@ fn base_address<T, D>(array: &PyArray<T, D>) -> usize {
     }
 }
 
-fn data_range<T, D>(array: &PyArray<T, D>) -> Range<usize>
+fn data_range<T, D>(array: &PyArray<T, D>) -> (usize, usize)
 where
     T: Element,
     D: Dimension,
@@ -657,7 +660,7 @@ where
     let mut end = 0;
 
     for (&dim, &stride) in array.shape().iter().zip(array.strides()) {
-        let offset = (dim as isize) * stride;
+        let offset = dim.saturating_sub(1) as isize * stride;
 
         if offset >= 0 {
             end += offset;
@@ -669,7 +672,7 @@ where
     let start = unsafe { data.offset(start) } as usize;
     let end = unsafe { data.offset(end) } as usize;
 
-    Range { start, end }
+    (start, end)
 }
 
 // FIXME(adamreichold): Use `usize::abs_diff` from std when that becomes stable.
@@ -713,8 +716,8 @@ mod tests {
             assert_eq!(base_address, array as *const _ as usize);
 
             let data_range = data_range(array);
-            assert_eq!(data_range.start, array.data() as usize);
-            assert_eq!(data_range.end, unsafe { array.data().add(15) } as usize);
+            assert_eq!(data_range.0, array.data() as usize);
+            assert_eq!(data_range.1, unsafe { array.data().add(5) } as usize);
         });
     }
 
@@ -731,8 +734,8 @@ mod tests {
             assert_eq!(base_address, base as usize);
 
             let data_range = data_range(array);
-            assert_eq!(data_range.start, array.data() as usize);
-            assert_eq!(data_range.end, unsafe { array.data().add(15) } as usize);
+            assert_eq!(data_range.0, array.data() as usize);
+            assert_eq!(data_range.1, unsafe { array.data().add(5) } as usize);
         });
     }
 
@@ -757,8 +760,8 @@ mod tests {
             assert_eq!(base_address, base as usize);
 
             let data_range = data_range(view);
-            assert_eq!(data_range.start, view.data() as usize);
-            assert_eq!(data_range.end, unsafe { view.data().add(12) } as usize);
+            assert_eq!(data_range.0, array.data() as usize);
+            assert_eq!(data_range.1, unsafe { array.data().add(3) } as usize);
         });
     }
 
@@ -787,8 +790,8 @@ mod tests {
             assert_eq!(base_address, base as usize);
 
             let data_range = data_range(view);
-            assert_eq!(data_range.start, view.data() as usize);
-            assert_eq!(data_range.end, unsafe { view.data().add(12) } as usize);
+            assert_eq!(data_range.0, array.data() as usize);
+            assert_eq!(data_range.1, unsafe { array.data().add(3) } as usize);
         });
     }
 
@@ -826,8 +829,8 @@ mod tests {
             assert_eq!(base_address, base as usize);
 
             let data_range = data_range(view2);
-            assert_eq!(data_range.start, view2.data() as usize);
-            assert_eq!(data_range.end, unsafe { view2.data().add(6) } as usize);
+            assert_eq!(data_range.0, array.data() as usize);
+            assert_eq!(data_range.1, array.data() as usize);
         });
     }
 
@@ -869,8 +872,8 @@ mod tests {
             assert_eq!(base_address, base as usize);
 
             let data_range = data_range(view2);
-            assert_eq!(data_range.start, view2.data() as usize);
-            assert_eq!(data_range.end, unsafe { view2.data().add(6) } as usize);
+            assert_eq!(data_range.0, array.data() as usize);
+            assert_eq!(data_range.1, array.data() as usize);
         });
     }
 
@@ -895,8 +898,9 @@ mod tests {
             assert_eq!(base_address, base as usize);
 
             let data_range = data_range(view);
-            assert_eq!(data_range.start, unsafe { view.data().offset(-9) } as usize);
-            assert_eq!(data_range.end, unsafe { view.data().offset(6) } as usize);
+            assert_eq!(view.data(), unsafe { array.data().offset(2) });
+            assert_eq!(data_range.0, unsafe { view.data().offset(-2) } as usize);
+            assert_eq!(data_range.1, unsafe { view.data().offset(3) } as usize);
         });
     }