main.c (1617B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 #include "stdlib/ndarray/base/min_view_buffer_index.h" 20 #include <stdint.h> 21 22 /** 23 * Computes the minimum linear index (in bytes) in an underlying data buffer accessible to an array view. 24 * 25 * @param ndims number of dimensions 26 * @param shape array shape (dimensions) 27 * @param strides array strides (in bytes) 28 * @param offset index offset 29 * @return minimum linear index 30 * 31 * @example 32 * #include "stdlib/ndarray/base/min_view_buffer_index.h" 33 * #include <stdint.h> 34 * 35 * int64_t ndims = 2; 36 * int64_t shape[] = { 10, 10 }; 37 * int64_t strides[] = { 10, 1 }; 38 * int64_t offset = 10; 39 * 40 * int64_t idx = stdlib_ndarray_min_view_buffer_index( ndims, shape, strides, offset ); 41 * // returns 10 42 */ 43 int64_t stdlib_ndarray_min_view_buffer_index( int64_t ndims, int64_t *shape, int64_t *strides, int64_t offset ) { 44 int64_t idx; 45 int64_t i; 46 47 idx = offset; 48 for ( i = 0; i < ndims; i++ ) { 49 if ( strides[ i ] < 0 ) { 50 idx += strides[ i ] * (shape[ i ] - 1); // decrements the index 51 } 52 } 53 return idx; 54 }