ndarray: add utility macros to simplify indexing arrays

1 files changed, 8 insertions, 0 deletions

diff --git a/ndarray.h b/ndarray.h
index f10ac80..c0d964b 100644
--- a/ndarray.h
+++ b/ndarray.h
@@ -45,6 +45,14 @@ typedef struct NDArray {
 
 #define NDARRAY_ALLOC_ZERO (1 << 0)
 
+#define NDIDX1D(arr, x)       (arr->stride[0] * x)
+#define NDIDX2D(arr, x, y)    (arr->stride[0] * y + arr->stride[1] * x)
+#define NDIDX3D(arr, x, y, z) (arr->stride[0] * z + arr->stride[1] * y + arr->stride[0] * x)
+
+#define NDPTR1D(arr, x)       (arr->data + NDIDX1D(arr, x))
+#define NDPTR2D(arr, x, y)    (arr->data + NDIDX2D(arr, x, y))
+#define NDPTR3D(arr, x, y, z) (arr->data + NDIDX2D(arr, x, y, z))
+
 int mg2di_ndarray_alloc(NDArray **result, unsigned int dims,
                         const size_t * const size, unsigned int flags);
 void mg2di_ndarray_free(NDArray **a);