Address performance bottleneck when resolving a data source's underlying data type

Author: kgryte

lib/node_modules/@stdlib/ndarray/lib/dtype.js

@@ -0,0 +1,83 @@
+/**
+* @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 isBuffer = require( '@stdlib/assert/is-buffer' );
+var isArray = require( '@stdlib/assert/is-array' );
+var Float64Array = require( '@stdlib/array/float64' );
+var Float32Array = require( '@stdlib/array/float32' );
+var Uint32Array = require( '@stdlib/array/uint32' );
+var Int32Array = require( '@stdlib/array/int32' );
+var Uint16Array = require( '@stdlib/array/uint16' );
+var Int16Array = require( '@stdlib/array/int16' );
+var Uint8Array = require( '@stdlib/array/uint8' );
+var Uint8ClampedArray = require( '@stdlib/array/uint8c' );
+var Int8Array = require( '@stdlib/array/int8' );
+var getType = require( '@stdlib/ndarray/base/buffer-dtype' );
+
+
+// VARIABLES //
+
+var TYPES = [
+	[ Float64Array, 'float64' ],
+	[ Float32Array, 'float32' ],
+	[ Uint32Array, 'uint32' ],
+	[ Int32Array, 'int32' ],
+	[ Uint16Array, 'uint16' ],
+	[ Int16Array, 'int16' ],
+	[ Uint8Array, 'uint8' ],
+	[ Uint8ClampedArray, 'uint8c' ],
+	[ Int8Array, 'int8' ]
+];
+var NTYPES = TYPES.length;
+
+
+// MAIN //
+
+/**
+* Resolves a data source underlying data type.
+*
+* @private
+* @param {(Array|TypedArray|Buffer)} buffer - data source
+* @returns {string} data type
+*/
+function dtype( buffer ) {
+	var i;
+	if ( isArray( buffer ) ) {
+		return 'generic';
+	}
+	if ( isBuffer( buffer ) ) {
+		return 'binary';
+	}
+	// By process of elimination, left with typed arrays...
+	for ( i = 0; i < NTYPES; i++ ) {
+		if ( buffer instanceof TYPES[ i ][ 0 ] ) {
+			return TYPES[ i ][ 1 ];
+		}
+	}
+	// If the above failed, fall back to a more robust (and significantly slower) means for resolving underlying data types:
+	return getType( buffer );
+}
+
+
+// EXPORTS //
+
+module.exports = dtype;

lib/node_modules/@stdlib/ndarray/lib/main.js

@@ -33,12 +33,12 @@ var ctor = require( '@stdlib/ndarray/ctor' );
 var mctor = require( '@stdlib/ndarray/memoized-ctor' );
 var isDataType = require( '@stdlib/ndarray/base/assert/is-data-type' );
 var isOrder = require( '@stdlib/ndarray/base/assert/is-order' );
-var getType = require( '@stdlib/ndarray/base/buffer-dtype' );
 var createBuffer = require( '@stdlib/ndarray/base/buffer' );
 var arrayShape = require( '@stdlib/array/shape' );
 var flattenArray = require( '@stdlib/utils/flatten-array' );
 var isArrayLikeObject = require( './is_array_like_object.js' );
 var defaults = require( './defaults.json' );
+var getType = require( './dtype.js' );
 var castBuffer = require( './cast_buffer.js' );
 var copyView = require( './copy_view.js' );