main.c (1887B)
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/minmax_view_buffer_index.h" 20 #include <stdint.h> 21 22 /** 23 * Computes the minimum and maximum linear indices (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 * @param out 2-element output array 30 * @return status code 31 * 32 * @example 33 * #include "stdlib/ndarray/base/minmax_view_buffer_index.h" 34 * #include <stdint.h> 35 * 36 * int64_t ndims = 2; 37 * int64_t shape[] = { 10, 10 }; 38 * int64_t strides[] = { 10, 1 }; 39 * int64_t offset = 0; 40 * int64_t out[ 2 ]; 41 * 42 * stdlib_ndarray_minmax_view_buffer_index( ndims, shape, strides, offset, out ); 43 * 44 * int64_t min = out[ 0 ]; 45 * // returns 0 46 * 47 * int64_t max = out[ 1 ]; 48 * // returns 99 49 */ 50 int8_t stdlib_ndarray_minmax_view_buffer_index( int64_t ndims, int64_t *shape, int64_t *strides, int64_t offset, int64_t *out ) { 51 int64_t min; 52 int64_t max; 53 int64_t s; 54 int64_t i; 55 56 min = offset; 57 max = offset; 58 for ( i = 0; i < ndims; i++ ) { 59 s = strides[ i ]; 60 if ( s > 0 ) { 61 max += s * ( shape[i]-1 ); 62 } else if ( s < 0 ) { 63 min += s * ( shape[i]-1 ); // decrements min 64 } 65 } 66 out[ 0 ] = min; 67 out[ 1 ] = max; 68 69 return 0; 70 }