Example works

lib/utils.js

@@ -0,0 +1,95 @@
+/*
+ * tar-js
+ * MIT (c) 2011 T. Jameson Little
+ */
+
+(function () {
+	"use strict";
+
+	require('require-kiss');
+
+	var lookup = [
+			'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+			'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+			'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+			'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+			'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+			'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+			'w', 'x', 'y', 'z', '0', '1', '2', '3',
+			'4', '5', '6', '7', '8', '9', '+', '/'
+		];
+	function clean(length) {
+		var i, buffer = new Uint8Array(length);
+		for (i = 0; i < length; i += 1) {
+			buffer[i] = 0;
+		}
+		return buffer;
+	}
+
+	function extend(orig, length, addLength, multipleOf) {
+		var newSize = length + addLength,
+			buffer = clean((parseInt(newSize / multipleOf) + 1) * multipleOf);
+
+		buffer.set(orig);
+
+		return buffer;
+	}
+
+	function pad(num, bytes, base) {
+		num = num.toString(base || 8);
+		return "000000000000".substr(num.length + 12 - bytes) + num;
+	}	
+	
+	function stringToUint8 (input, out, offset) {
+		var i, length;
+
+		out = out || clean(input.length);
+
+		offset = offset || 0;
+		for (i = 0, length = input.length; i < length; i += 1) {
+			out[offset] = input.charCodeAt(i);
+			offset += 1;
+		}
+
+		return out;
+	}
+
+	function uint8ToBase64(uint8) {
+		var i,
+			extraBytes = uint8.length % 3, // if we have 1 byte left, pad 2 bytes
+			output = "",
+			temp, length;
+
+		function tripletToBase64 (num) {
+			return lookup[num >> 18 & 0x3F] + lookup[num >> 12 & 0x3F] + lookup[num >> 6 & 0x3F] + lookup[num & 0x3F];
+		};
+
+		// go through the array every three bytes, we'll deal with trailing stuff later
+		for (i = 0, length = uint8.length - extraBytes; i < length; i += 3) {
+			temp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2]);
+			output += tripletToBase64(temp);
+		}
+
+		// this prevents an ERR_INVALID_URL in Chrome (Firefox okay)
+		switch (output.length % 4) {
+			case 1:
+				output += '=';
+				break;
+			case 2:
+				output += '==';
+				break;
+			default:
+				break;
+		}
+
+		return output;
+	}
+
+	module.exports.clean = clean;
+	module.exports.pad = pad;
+	module.exports.extend = extend;
+	module.exports.stringToUint8 = stringToUint8;
+	module.exports.uint8ToBase64 = uint8ToBase64;
+
+	provide('utils');
+}());