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var constant = require('../utility/constant'),
isNative = require('../lang/isNative');
/** Native method references. */
var ArrayBuffer = isNative(ArrayBuffer = global.ArrayBuffer) && ArrayBuffer,
bufferSlice = isNative(bufferSlice = ArrayBuffer && new ArrayBuffer(0).slice) && bufferSlice,
floor = Math.floor,
Uint8Array = isNative(Uint8Array = global.Uint8Array) && Uint8Array;
/** Used to clone array buffers. */
var Float64Array = (function() {
// Safari 5 errors when using an array buffer to initialize a typed array
// where the array buffer's `byteLength` is not a multiple of the typed
// array's `BYTES_PER_ELEMENT`.
try {
var func = isNative(func = global.Float64Array) && func,
result = new func(new ArrayBuffer(10), 0, 1) && func;
} catch(e) {}
return result;
}());
/** Used as the size, in bytes, of each `Float64Array` element. */
var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT : 0;
/**
* Creates a clone of the given array buffer.
*
* @private
* @param {ArrayBuffer} buffer The array buffer to clone.
* @returns {ArrayBuffer} Returns the cloned array buffer.
*/
function bufferClone(buffer) {
return bufferSlice.call(buffer, 0);
}
if (!bufferSlice) {
// PhantomJS has `ArrayBuffer` and `Uint8Array` but not `Float64Array`.
bufferClone = !(ArrayBuffer && Uint8Array) ? constant(null) : function(buffer) {
var byteLength = buffer.byteLength,
floatLength = Float64Array ? floor(byteLength / FLOAT64_BYTES_PER_ELEMENT) : 0,
offset = floatLength * FLOAT64_BYTES_PER_ELEMENT,
result = new ArrayBuffer(byteLength);
if (floatLength) {
var view = new Float64Array(result, 0, floatLength);
view.set(new Float64Array(buffer, 0, floatLength));
}
if (byteLength != offset) {
view = new Uint8Array(result, offset);
view.set(new Uint8Array(buffer, offset));
}
return result;
};
}
module.exports = bufferClone;
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