All files / shape2strides/lib assign.js

70.87% Statements 73/103
100% Branches 1/1
0% Functions 0/3
70.87% Lines 73/103

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 1041x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x                           1x 1x 1x 1x 1x 1x 1x 1x 1x                       1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x             1x 1x 1x 1x 1x  
/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 
'use strict';
 
// MODULES //
 
var isColumnMajor = require( '@stdlib/ndarray/base/assert/is-column-major-string' );
 
 
// FUNCTIONS //
 
/**
* Generates a stride array from an array shape (row-major).
*
* @private
* @param {NonNegativeIntegerArray} shape - array shape
* @param {(Array|TypedArray|Object)} out - output object
* @returns {(Array|TypedArray|Object)} array strides
*/
function rowmajor( shape, out ) {
	var ndims;
	var s;
	var i;

	ndims = shape.length;
	s = 1;
	for ( i = ndims-1; i >= 0; i-- ) {
		out[ i ] = s;
		s *= shape[ i ];
	}
	return out;
}
 
/**
* Generates a stride array from an array shape (column-major).
*
* @private
* @param {NonNegativeIntegerArray} shape - array shape
* @param {(Array|TypedArray|Object)} out - output object
* @returns {(Array|TypedArray|Object)} array strides
*/
function columnmajor( shape, out ) {
	var s;
	var i;

	s = 1;
	for ( i = 0; i < shape.length; i++ ) {
		out[ i ] = s;
		s *= shape[ i ];
	}
	return out;
}
 
 
// MAIN //
 
/**
* Generates a stride array from an array shape.
*
* @param {NonNegativeIntegerArray} shape - array shape
* @param {string} order - specifies whether an array is row-major (C-style) or column-major (Fortran-style)
* @param {(Array|TypedArray|Object)} out - output object
* @returns {(Array|TypedArray|Object)} array strides
*
* @example
* var strides = [ 0, 0 ];
*
* var out = shape2strides( [ 3, 2 ], 'row-major', strides );
* // returns [ 2, 1 ]
*
* var bool = ( out === strides );
* // returns true
*
* out = shape2strides( [ 3, 2 ], 'column-major', strides );
* // returns [ 1, 3 ]
*/
function shape2strides( shape, order, out ) {
	if ( isColumnMajor( order ) ) {
		return columnmajor( shape, out );
	}
	return rowmajor( shape, out );
}
 
 
// EXPORTS //
 
module.exports = shape2strides;