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Increase speed 2x by using prototypes and ordering the switch stateme…
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…nts differently
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@creationix
creationix committed Jul 4, 2012
1 parent e158caf commit 6b0b073
Showing 1 changed file with 169 additions and 165 deletions.
334 changes: 169 additions & 165 deletions msgpack.js
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Expand Up @@ -15,177 +15,181 @@ exports.decode = decode;
// Also I've added a type for `undefined`
// undefined 11000100 0xc4

function decode(buffer, offset) {
var offset = 0;
function map(length) {
var value = {};
for (var i = 0; i < length; i++) {
var key = parse();
value[key] = parse();
}
return value;
function Decoder(buffer, offset) {
this.offset = offset || 0;
this.buffer = buffer;
}
Decoder.prototype.map = function (length) {
var value = {};
for (var i = 0; i < length; i++) {
var key = this.parse();
value[key] = this.parse();
}
function buf(length) {
var value = buffer.slice(offset, offset + length);
offset += length;
return value;
return value;
};
Decoder.prototype.buf = function (length) {
var value = this.buffer.slice(this.offset, this.offset + length);
this.offset += length;
return value;
};
Decoder.prototype.raw = function (length) {
var value = this.buffer.toString('utf8', this.offset, this.offset + length);
this.offset += length;
return value;
};
Decoder.prototype.array = function (length) {
var value = new Array(length);
for (var i = 0; i < length; i++) {
value[i] = this.parse();
}
function raw(length) {
var value = buffer.toString('utf8', offset, offset + length);
offset += length;
return value;
return value;
};
Decoder.prototype.parse = function () {
var type = this.buffer[this.offset];
var value, length;
// FixRaw
if ((type & 0xe0) === 0xa0) {
length = type & 0x1f;
this.offset++;
return this.raw(length);
}
function array(length) {
var value = new Array(length);
for (var i = 0; i < length; i++) {
value[i] = parse();
}
// FixMap
if ((type & 0xf0) === 0x80) {
length = type & 0x0f;
this.offset++;
return this.map(length);
}
// FixArray
if ((type & 0xf0) === 0x90) {
length = type & 0x0f;
this.offset++;
return this.array(length);
}
// Positive FixNum
if ((type & 0x80) === 0x00) {
this.offset++;
return type;
}
// Negative Fixnum
if ((type & 0xe0) === 0xe0) {
value = this.buffer.readInt8(this.offset);
this.offset++;
return value;
}
function parse() {
var type = buffer[offset];
var value, length;
switch (type) {
// nil
case 0xc0:
offset++;
return null;
// false
case 0xc2:
offset++;
return false;
// true
case 0xc3:
offset++;
return true;
// undefined
case 0xc4:
offset++;
return undefined;
// float
case 0xca:
value = buffer.readFloatBE(offset + 1);
offset += 5;
return value;
// double
case 0xcb:
value = buffer.readDoubleBE(offset + 1);
offset += 9;
return value;
// uint8
case 0xcc:
value = buffer[offset + 1];
offset += 2;
return value;
// uint 16
case 0xcd:
value = buffer.readUInt16BE(offset + 1);
offset += 3;
return value;
// uint 32
case 0xce:
value = buffer.readUInt32BE(offset + 1);
offset += 5;
return value;
// uint64
case 0xcf:
value = buffer.readUInt64BE(offset + 1);
offset += 9;
return value;
// int 8
case 0xd0:
value = buffer.readInt8(offset + 1);
offset += 2;
return value;
// int 16
case 0xd1:
value = buffer.readInt16BE(offset + 1);
offset += 3;
return value;
// int 32
case 0xd2:
value = buffer.readInt32BE(offset + 1);
offset += 5;
return value;
// int 64
case 0xd3:
value = buffer.readInt64BE(offset + 1);
offset += 9;
return value;
// map 16
case 0xde:
length = buffer.readUInt16BE(offset + 1);
offset += 3;
return map(length);
// map 32
case 0xdf:
length = buffer.readUInt32BE(offset + 1);
offset += 5;
return map(length);
// array 16
case 0xdc:
length = buffer.readUInt16BE(offset + 1);
offset += 3;
return array(length);
// array 32
case 0xdd:
length = buffer.readUInt32BE(offset + 1);
offset += 5;
return array(length);
// buffer 16
case 0xd8:
length = buffer.readUInt16BE(offset + 1);
offset += 3;
return buf(length);
// buffer 32
case 0xd9:
length = buffer.readUInt32BE(offset + 1);
offset += 5;
return buf(length);
// raw 16
case 0xda:
length = buffer.readUInt16BE(offset + 1);
offset += 3;
return raw(length);
// raw 32
case 0xdb:
length = buffer.readUInt32BE(offset + 1);
offset += 5;
return raw(length);
}
// FixRaw
if ((type & 0xe0) === 0xa0) {
length = type & 0x1f;
offset++;
return raw(length);
}
// FixMap
if ((type & 0xf0) === 0x80) {
length = type & 0x0f;
offset++;
return map(length);
}
// FixArray
if ((type & 0xf0) === 0x90) {
length = type & 0x0f;
offset++;
return array(length);
}
// Positive FixNum
if ((type & 0x80) === 0x00) {
offset++;
return type;
}
// Negative Fixnum
if ((type & 0xe0) === 0xe0) {
value = buffer.readInt8(offset);
offset++;
return value;
}
throw new Error("Unknown type 0x" + type.toString(16));
switch (type) {
// raw 16
case 0xda:
length = this.buffer.readUInt16BE(this.offset + 1);
this.offset += 3;
return this.raw(length);
// raw 32
case 0xdb:
length = this.buffer.readUInt32BE(this.offset + 1);
this.offset += 5;
return this.raw(length);
// nil
case 0xc0:
this.offset++;
return null;
// false
case 0xc2:
this.offset++;
return false;
// true
case 0xc3:
this.offset++;
return true;
// undefined
case 0xc4:
this.offset++;
return undefined;
// uint8
case 0xcc:
value = this.buffer[this.offset + 1];
this.offset += 2;
return value;
// uint 16
case 0xcd:
value = this.buffer.readUInt16BE(this.offset + 1);
this.offset += 3;
return value;
// uint 32
case 0xce:
value = this.buffer.readUInt32BE(this.offset + 1);
this.offset += 5;
return value;
// uint64
case 0xcf:
value = this.buffer.readUInt64BE(this.offset + 1);
this.offset += 9;
return value;
// int 8
case 0xd0:
value = this.buffer.readInt8(this.offset + 1);
this.offset += 2;
return value;
// int 16
case 0xd1:
value = this.buffer.readInt16BE(this.offset + 1);
this.offset += 3;
return value;
// int 32
case 0xd2:
value = this.buffer.readInt32BE(this.offset + 1);
this.offset += 5;
return value;
// int 64
case 0xd3:
value = this.buffer.readInt64BE(this.offset + 1);
this.offset += 9;
return value;
// map 16
case 0xde:
length = this.buffer.readUInt16BE(this.offset + 1);
this.offset += 3;
return this.map(length);
// map 32
case 0xdf:
length = this.buffer.readUInt32BE(this.offset + 1);
this.offset += 5;
return this.map(length);
// array 16
case 0xdc:
length = this.buffer.readUInt16BE(this.offset + 1);
this.offset += 3;
return this.array(length);
// array 32
case 0xdd:
length = this.buffer.readUInt32BE(this.offset + 1);
this.offset += 5;
return this.array(length);
// buffer 16
case 0xd8:
length = this.buffer.readUInt16BE(this.offset + 1);
this.offset += 3;
return this.buf(length);
// buffer 32
case 0xd9:
length = this.buffer.readUInt32BE(this.offset + 1);
this.offset += 5;
return this.buf(length);
// float
case 0xca:
value = this.buffer.readFloatBE(this.offset + 1);
this.offset += 5;
return value;
// double
case 0xcb:
value = this.buffer.readDoubleBE(this.offset + 1);
this.offset += 9;
return value;
}
var value = parse();
if (offset !== buffer.length) throw new Error((buffer.length - offset) + " trailing bytes");
throw new Error("Unknown type 0x" + type.toString(16));
};
function decode(buffer) {
var decoder = new Decoder(buffer);
var value = decoder.parse();
if (decoder.offset !== buffer.length) throw new Error((buffer.length - decoder.offset) + " trailing bytes");
return value;
}

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1 comment on commit 6b0b073

@creationix
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This is much faster than JSON.parse for number-heavy workloads. String-heavy workloads are still slower than JSON.parse because Buffer.prototype.toString is so slow.

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