Differential D7997 Diff 27117 lib/media/data-utils.js

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lib/media/data-utils.js

	// @flow			// @flow

	import { fileInfoFromData } from './file-utils.js';
	import { base64FromIntArray } from '../utils/third-party/base64.js';

	/**			/**
	* Returns a hex string representation of the given Uint8Array.			* Returns a hex string representation of the given Uint8Array.
	*/			*/
	function uintArrayToHexString(data: Uint8Array): string {			function uintArrayToHexString(data: Uint8Array): string {
	return Array.from(data)			return Array.from(data)
	.map(byte => byte.toString(16).padStart(2, '0'))			.map(byte => byte.toString(16).padStart(2, '0'))
	.join('');			.join('');
	}			}

	/**			/**
	* Returns a Uint8Array representation of the given hex string.			* Returns a Uint8Array representation of the given hex string.
	*/			*/
	function hexToUintArray(hex: string): Uint8Array {			function hexToUintArray(hex: string): Uint8Array {
	const result = new Uint8Array(hex.length / 2);			const result = new Uint8Array(hex.length / 2);
	for (let i = 0; i < hex.length; i += 2) {			for (let i = 0; i < hex.length; i += 2) {
	result[i / 2] = parseInt(hex.substr(i, 2), 16);			result[i / 2] = parseInt(hex.substr(i, 2), 16);
	}			}
	return result;			return result;
	}			}

	/**			export { uintArrayToHexString, hexToUintArray };
	* Returns a data URL representation of the given Uint8Array.
	* Returns `null` if MIME type cannot be determined by reading the data header.
	*/
	function uintArrayToDataURL(bytes: Uint8Array): ?string {
	const base64 = base64FromIntArray(bytes);
	const { mime } = fileInfoFromData(bytes);
	if (!mime) {
	return null;
	}
	return `data:${mime};base64,${base64}`;
	}

	export {
	uintArrayToHexString,
	hexToUintArray,
	base64FromIntArray,
	uintArrayToDataURL,
	};