time-to-botec/squiggle/node_modules/@stdlib/array/same-kind-casts/lib/main.js

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/**
* @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 objectKeys = require( '@stdlib/utils/keys' );
var hasOwnProp = require( '@stdlib/assert/has-own-property' );
var SAME_KIND_CASTS = require( './same_kind_casts.json' );
// VARIABLES //
var TABLE;
// FUNCTIONS //
/**
* Generates a full table of same "kind" casts for each array data type.
*
* @private
* @returns {Object} table
*/
function generateFullTable() {
var dtypes;
var ntypes;
var out;
var tmp;
var dt1;
var dt2;
var o;
var j;
var i;
out = {};
dtypes = objectKeys( SAME_KIND_CASTS );
ntypes = dtypes.length;
for ( i = 0; i < ntypes; i++ ) {
dt1 = dtypes[ i ];
o = SAME_KIND_CASTS[ dt1 ];
tmp = {};
for ( j = 0; j < ntypes; j++ ) {
dt2 = dtypes[ j ];
tmp[ dt2 ] = o[ dt2 ];
}
out[ dt1 ] = tmp;
}
return out;
}
/**
* Generates a table of same "kind" casts for each array data type.
*
* @private
* @returns {Object} table
*/
function generateTable() {
var dtypes;
var ntypes;
var out;
var tmp;
var dt1;
var dt2;
var o;
var j;
var i;
out = {};
dtypes = objectKeys( SAME_KIND_CASTS );
ntypes = dtypes.length;
for ( i = 0; i < ntypes; i++ ) {
dt1 = dtypes[ i ];
o = SAME_KIND_CASTS[ dt1 ];
tmp = [];
for ( j = 0; j < ntypes; j++ ) {
dt2 = dtypes[ j ];
if ( o[ dt2 ] === 1 ) {
tmp.push( dt2 );
}
}
out[ dt1 ] = tmp;
}
return out;
}
// MAIN //
/**
* Returns a list of array data types to which a provided array data type can be safely cast or cast within the same "kind".
*
* @param {string} [dtype] - array data type
* @returns {(Object|StringArray|null)} list of array data types or null
*
* @example
* var list = sameKindCasts( 'float32' );
* // returns [...]
*/
function sameKindCasts( dtype ) {
if ( arguments.length === 0 ) {
return generateFullTable();
}
if ( TABLE === void 0 ) {
// Lazily generate table...
TABLE = generateTable();
}
if ( hasOwnProp( TABLE, dtype ) ) {
return TABLE[ dtype ].slice();
}
return null;
}
// EXPORTS //
module.exports = sameKindCasts;