Initial working version

node_modules/audio-metadata/src/utils.js

@@ -0,0 +1,69 @@
+function toArrayBuffer(buffer) {
+	var arrayBuffer = new ArrayBuffer(buffer.length);
+	var view = new Uint8Array(arrayBuffer);
+	for (var i = 0; i < buffer.length; ++i) {
+		view[i] = buffer[i];
+	}
+	return arrayBuffer;
+}
+
+module.exports = {
+	trimNull: function(s) {
+		return s.replace(/\u0000+$/, '');
+	},
+
+	createView: function(buffer) {
+		if (typeof(Buffer) !== 'undefined' && buffer instanceof Buffer) {
+			//convert nodejs buffers to ArrayBuffer
+			buffer = toArrayBuffer(buffer);
+		}
+
+		if (!(buffer instanceof ArrayBuffer)) {
+			throw new Error('Expected instance of Buffer or ArrayBuffer');
+		}
+
+		return new DataView(buffer);
+	},
+
+	readBytes: function(view, offset, length, target) {
+		if (offset + length < 0) {
+			return [];
+		}
+
+		var bytes = [];
+		var max = Math.min(offset + length, view.byteLength);
+		for (var i = offset; i < max; i++) {
+			var value = view.getUint8(i);
+			bytes.push(value);
+			if (target) {
+				target.setUint8(i - offset, value);
+			}
+		}
+
+		return bytes;
+	},
+
+	readAscii: function(view, offset, length) {
+		if (view.byteLength < offset + length) {
+			return '';
+		}
+		var s = '';
+		for (var i = 0; i < length; i++) {
+			s += String.fromCharCode(view.getUint8(offset + i));
+		}
+
+		return s;
+	},
+
+	readUtf8: function(view, offset, length) {
+		if (view.byteLength < offset + length) {
+			return '';
+		}
+
+		var buffer = view.buffer.slice(offset, offset + length);
+
+		//http://stackoverflow.com/a/17192845 - convert byte array to UTF8 string
+		var encodedString = String.fromCharCode.apply(null, new Uint8Array(buffer));
+		return decodeURIComponent(escape(encodedString));
+	}
+};