msgpack-lite/lib/write-type.js

// write-type.js

exports.type = {
  "boolean": bool,
  "function": nil,
  "number": number,
  "object": object,
  "string": string,
  "symbol": nil,
  "undefined": nil
};

var BufferLite = require("./buffer-lite");
var token = require("./write-token").token;
var encode = require("./write-core").encode;
var uint8 = require("./write-uint8").uint8;
var codec = require("./ext-preset").preset;
var ExtBuffer = require("./ext-buffer").ExtBuffer;

var IS_BUFFER_SHIM = ("TYPED_ARRAY_SUPPORT" in Buffer);
var IS_ARRAY = Array.isArray || isArray;

function bool(encoder, value) {
  // false -- 0xc2
  // true -- 0xc3
  var type = value ? 0xc3 : 0xc2;
  token[type](encoder, value);
}

function number(encoder, value) {
  var ivalue = value | 0;
  var type;
  if (value !== ivalue) {
    // float 64 -- 0xcb
    type = 0xcb;
    token[type](encoder, value);
    return;
  } else if (-0x20 <= ivalue && ivalue <= 0x7F) {
    // positive fixint -- 0x00 - 0x7f
    // negative fixint -- 0xe0 - 0xff
    type = ivalue & 0xFF;
  } else if (0 <= ivalue) {
    // uint 8 -- 0xcc
    // uint 16 -- 0xcd
    // uint 32 -- 0xce
    // uint 64 -- 0xcf
    type = (ivalue <= 0xFF) ? 0xcc : (ivalue <= 0xFFFF) ? 0xcd : 0xce;
  } else {
    // int 8 -- 0xd0
    // int 16 -- 0xd1
    // int 32 -- 0xd2
    // int 64 -- 0xd3
    type = (-0x80 <= ivalue) ? 0xd0 : (-0x8000 <= ivalue) ? 0xd1 : 0xd2;
  }
  token[type](encoder, ivalue);
}

function string(encoder, value) {
  // str 8 -- 0xd9
  // str 16 -- 0xda
  // str 32 -- 0xdb
  // fixstr -- 0xa0 - 0xbf

  // prepare buffer
  var length = value.length;
  var maxsize = 5 + length * 3;
  encoder.reserve(maxsize);

  // expected header size
  var expected = (length < 32) ? 1 : (length <= 0xFF) ? 2 : (length <= 0xFFFF) ? 3 : 5;

  // expected start point
  var start = encoder.offset + expected;

  // write string
  length = BufferLite.writeString.call(encoder.buffer, value, start);

  // actual header size
  var actual = (length < 32) ? 1 : (length <= 0xFF) ? 2 : (length <= 0xFFFF) ? 3 : 5;

  // move content when needed
  if (expected !== actual) {
    var targetStart = encoder.offset + actual;
    var end = start + length;
    if (IS_BUFFER_SHIM) {
      BufferLite.copy.call(encoder.buffer, encoder.buffer, targetStart, start, end);
    } else {
      encoder.buffer.copy(encoder.buffer, targetStart, start, end);
    }
  }

  // write header
  var type = (actual === 1) ? (0xa0 + length) : (actual <= 3) ? 0xd7 + actual : 0xdb;
  token[type](encoder, length);

  // move cursor
  encoder.offset += length;
}

var extmap = [];
extmap[1] = 0xd4;
extmap[2] = 0xd5;
extmap[4] = 0xd6;
extmap[8] = 0xd7;
extmap[16] = 0xd8;

function object(encoder, value) {
  if (IS_ARRAY(value)) return array(encoder, value);
  if (value === null) return nil(encoder, value);
  var packer = codec.getExtPacker(value);
  if (packer) value = packer(value);
  if (value instanceof ExtBuffer) return ext(encoder, value);
  if (Buffer.isBuffer(value)) return bin(encoder, value);
  map(encoder, value);
}

function nil(encoder, value) {
  // nil -- 0xc0
  var type = 0xc0;
  token[type](encoder, value);
}

function array(encoder, value) {
  // fixarray -- 0x90 - 0x9f
  // array 16 -- 0xdc
  // array 32 -- 0xdd
  var length = value.length;
  var type = (length < 16) ? (0x90 + length) : (length <= 0xFFFF) ? 0xdc : 0xdd;
  token[type](encoder, length);
  for (var i = 0; i < length; i++) {
    encode(encoder, value[i]);
  }
}

function bin(encoder, value) {
  // bin 8 -- 0xc4
  // bin 16 -- 0xc5
  // bin 32 -- 0xc6
  var length = value.length;
  var type = (length < 0xFF) ? 0xc4 : (length <= 0xFFFF) ? 0xc5 : 0xc6;
  token[type](encoder, length);
  encoder.send(value);
}

function ext(encoder, value) {
  // fixext 1 -- 0xd4
  // fixext 2 -- 0xd5
  // fixext 4 -- 0xd6
  // fixext 8 -- 0xd7
  // fixext 16 -- 0xd8
  // ext 8 -- 0xc7
  // ext 16 -- 0xc8
  // ext 32 -- 0xc9
  var buffer = value.buffer;
  var length = buffer.length;
  var type = extmap[length] || ((length < 0xFF) ? 0xc7 : (length <= 0xFFFF) ? 0xc8 : 0xc9);
  token[type](encoder, length);
  uint8[value.type](encoder);
  encoder.send(buffer);
}

function map(encoder, value) {
  // fixmap -- 0x80 - 0x8f
  // map 16 -- 0xde
  // map 32 -- 0xdf
  var keys = Object.keys(value);
  var length = keys.length;
  var type = (length < 16) ? (0x80 + length) : (length <= 0xFFFF) ? 0xde : 0xdf;
  token[type](encoder, length);
  keys.forEach(function(key) {
    encode(encoder, key);
    encode(encoder, value[key]);
  });
}

function isArray(array) {
  return "[object Array]" === Object.prototype.toString.call(array);
}