feat(browser): switch from Buffer polyfill to ArrayBuffer (#1)

README.md

@@ -27,7 +27,7 @@ var decoded = notepack.decode(encoded); // { foo: 'bar' }
 
 ## Browser
 
-A browser version of notepack is also available (29.5 kB minified)
+A browser version of notepack is also available (7.6 kB minified)
 
 ```html
 <script src="https://rawgit.com/darrachequesne/notepack/master/dist/notepack.js"></script>

browser/decode.js

@@ -0,0 +1,276 @@
+'use strict';
+
+function Decoder(buffer) {
+  this.offset = 0;
+  if (buffer instanceof ArrayBuffer) {
+    this.buffer = buffer;
+  } else if (ArrayBuffer.isView(buffer)) {
+    this.buffer = buffer.buffer;
+  } else {
+    throw new Error('Invalid argument');
+  }
+  this.view = new DataView(buffer);
+}
+
+function utf8Read(view, offset, length) {
+  var string = '';
+  for (var i = offset, end = offset + length; i < end; i++) {
+    var byte = view.getUint8(i);
+    if ((byte & 0x80) === 0x00) {
+      string += String.fromCharCode(byte);
+      continue;
+    }
+    if ((byte & 0xe0) === 0xc0) {
+      string += String.fromCharCode(
+        ((byte & 0x0f) << 6) |
+        (view.getUint8(++i) & 0x3f)
+      );
+      continue;
+    }
+    if ((byte & 0xf0) === 0xe0) {
+      string += String.fromCharCode(
+        ((byte & 0x0f) << 12) |
+        ((view.getUint8(++i) & 0x3f) << 6) |
+        ((view.getUint8(++i) & 0x3f) << 0)
+      );
+      continue;
+    }
+    if ((byte & 0xf8) === 0xf0) {
+      string += String.fromCharCode(
+        ((byte & 0x07) << 18) |
+        ((view.getUint8(++i) & 0x3f) << 12) |
+        ((view.getUint8(++i) & 0x3f) << 6) |
+        ((view.getUint8(++i) & 0x3f) << 0)
+      );
+      continue;
+    }
+    throw new Error('Invalid byte ' + byte.toString(16));
+  }
+  return string;
+}
+
+Decoder.prototype.array = function (length) {
+  var value = new Array(length);
+  for (var i = 0; i < length; i++) {
+    value[i] = this.parse();
+  }
+  return value;
+};
+
+Decoder.prototype.map = function (length) {
+  var key = '', value = {};
+  for (var i = 0; i < length; i++) {
+    key = this.parse();
+    value[key] = this.parse();
+  }
+  return value;
+};
+
+Decoder.prototype.str = function (length) {
+  var value = utf8Read(this.view, this.offset, length);
+  this.offset += length;
+  return value;
+};
+
+Decoder.prototype.bin = function (length) {
+  var value = this.buffer.slice(this.offset, this.offset + length);
+  this.offset += length;
+  return value;
+};
+
+Decoder.prototype.parse = function () {
+  var prefix = this.view.getUint8(this.offset++);
+  var value, length = 0, type = 0, hi = 0, lo = 0;
+
+  if (prefix < 0xc0) {
+    // positive fixint
+    if (prefix < 0x80) {
+      return prefix;
+    }
+    // fixmap
+    if (prefix < 0x90) {
+      return this.map(prefix & 0x0f);
+    }
+    // fixarray
+    if (prefix < 0xa0) {
+      return this.array(prefix & 0x0f);
+    }
+    // fixstr
+    return this.str(prefix & 0x1f);
+  }
+
+  // negative fixint
+  if (prefix > 0xdf) {
+    return (0xff - prefix + 1) * -1;
+  }
+
+  switch (prefix) {
+    // nil
+    case 0xc0:
+      return null;
+    // false
+    case 0xc2:
+      return false;
+    // true
+    case 0xc3:
+      return true;
+
+    // bin
+    case 0xc4:
+      length = this.view.getUint8(this.offset);
+      this.offset += 1;
+      return this.bin(length);
+    case 0xc5:
+      length = this.view.getUint16(this.offset);
+      this.offset += 2;
+      return this.bin(length);
+    case 0xc6:
+      length = this.view.getUint32(this.offset);
+      this.offset += 4;
+      return this.bin(length);
+
+    // ext
+    case 0xc7:
+      length = this.view.getUint8(this.offset);
+      type = this.view.getInt8(this.offset + 1);
+      this.offset += 2;
+      return [type, this.bin(length)];
+    case 0xc8:
+      length = this.view.getUint16(this.offset);
+      type = this.view.getInt8(this.offset + 2);
+      this.offset += 3;
+      return [type, this.bin(length)];
+    case 0xc9:
+      length = this.view.getUint32(this.offset);
+      type = this.view.getInt8(this.offset + 4);
+      this.offset += 5;
+      return [type, this.bin(length)];
+
+    // float
+    case 0xca:
+      value = this.view.getFloat32(this.offset);
+      this.offset += 4;
+      return value;
+    case 0xcb:
+      value = this.view.getFloat64(this.offset);
+      this.offset += 8;
+      return value;
+
+    // uint
+    case 0xcc:
+      value = this.view.getUint8(this.offset);
+      this.offset += 1;
+      return value;
+    case 0xcd:
+      value = this.view.getUint16(this.offset);
+      this.offset += 2;
+      return value;
+    case 0xce:
+      value = this.view.getUint32(this.offset);
+      this.offset += 4;
+      return value;
+    case 0xcf:
+      hi = this.view.getUint32(this.offset) * Math.pow(2, 32);
+      lo = this.view.getUint32(this.offset + 4);
+      this.offset += 8;
+      return hi + lo;
+
+    // int
+    case 0xd0:
+      value = this.view.getInt8(this.offset);
+      this.offset += 1;
+      return value;
+    case 0xd1:
+      value = this.view.getInt16(this.offset);
+      this.offset += 2;
+      return value;
+    case 0xd2:
+      value = this.view.getInt32(this.offset);
+      this.offset += 4;
+      return value;
+    case 0xd3:
+      hi = this.view.getInt32(this.offset) * Math.pow(2, 32);
+      lo = this.view.getUint32(this.offset + 4);
+      this.offset += 8;
+      return hi + lo;
+
+    // fixext
+    case 0xd4:
+      type = this.view.getInt8(this.offset);
+      this.offset += 1;
+      if (type === 0x00) {
+        this.offset += 1;
+        return void 0;
+      }
+      return [type, this.bin(1)];
+    case 0xd5:
+      type = this.view.getInt8(this.offset);
+      this.offset += 1;
+      return [type, this.bin(2)];
+    case 0xd6:
+      type = this.view.getInt8(this.offset);
+      this.offset += 1;
+      return [type, this.bin(4)];
+    case 0xd7:
+      type = this.view.getInt8(this.offset);
+      this.offset += 1;
+      if (type === 0x00) {
+        hi = this.view.getInt32(this.offset) * Math.pow(2, 32);
+        lo = this.view.getUint32(this.offset + 4);
+        this.offset += 8;
+        return new Date(hi + lo);
+      }
+      return [type, this.bin(8)];
+    case 0xd8:
+      type = this.view.getInt8(this.offset);
+      this.offset += 1;
+      return [type, this.bin(16)];
+
+    // str
+    case 0xd9:
+      length = this.view.getUint8(this.offset);
+      this.offset += 1;
+      return this.str(length);
+    case 0xda:
+      length = this.view.getUint16(this.offset);
+      this.offset += 2;
+      return this.str(length);
+    case 0xdb:
+      length = this.view.getUint32(this.offset);
+      this.offset += 4;
+      return this.str(length);
+
+    // array
+    case 0xdc:
+      length = this.view.getUint16(this.offset);
+      this.offset += 2;
+      return this.array(length);
+    case 0xdd:
+      length = this.view.getUint32(this.offset);
+      this.offset += 4;
+      return this.array(length);
+
+    // map
+    case 0xde:
+      length = this.view.getUint16(this.offset);
+      this.offset += 2;
+      return this.map(length);
+    case 0xdf:
+      length = this.view.getUint32(this.offset);
+      this.offset += 4;
+      return this.map(length);
+  }
+
+  throw new Error('Could not parse');
+};
+
+function decode(buffer) {
+  var decoder = new Decoder(buffer);
+  var value = decoder.parse();
+  if (decoder.offset !== buffer.byteLength) {
+    throw new Error((buffer.byteLength - decoder.offset) + ' trailing bytes');
+  }
+  return value;
+}
+
+module.exports = decode;