cbor.js

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2016 Patrick Gansterer <paroga@paroga.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

(function(global, undefined) { "use strict";
var POW_2_24 = 5.960464477539063e-8,
    POW_2_32 = 4294967296,
    POW_2_53 = 9007199254740992;

function encode(value) {
  var data = new ArrayBuffer(256);
  var dataView = new DataView(data);
  var lastLength;
  var offset = 0;

  function prepareWrite(length) {
    var newByteLength = data.byteLength;
    var requiredLength = offset + length;
    while (newByteLength < requiredLength)
      newByteLength <<= 1;
    if (newByteLength !== data.byteLength) {
      var oldDataView = dataView;
      data = new ArrayBuffer(newByteLength);
      dataView = new DataView(data);
      var uint32count = (offset + 3) >> 2;
      for (var i = 0; i < uint32count; ++i)
        dataView.setUint32(i << 2, oldDataView.getUint32(i << 2));
    }

    lastLength = length;
    return dataView;
  }
  function commitWrite() {
    offset += lastLength;
  }
  function writeFloat64(value) {
    commitWrite(prepareWrite(8).setFloat64(offset, value));
  }
  function writeUint8(value) {
    commitWrite(prepareWrite(1).setUint8(offset, value));
  }
  function writeUint8Array(value) {
    var dataView = prepareWrite(value.length);
    for (var i = 0; i < value.length; ++i)
      dataView.setUint8(offset + i, value[i]);
    commitWrite();
  }
  function writeUint16(value) {
    commitWrite(prepareWrite(2).setUint16(offset, value));
  }
  function writeUint32(value) {
    commitWrite(prepareWrite(4).setUint32(offset, value));
  }
  function writeUint64(value) {
    var low = value % POW_2_32;
    var high = (value - low) / POW_2_32;
    var dataView = prepareWrite(8);
    dataView.setUint32(offset, high);
    dataView.setUint32(offset + 4, low);
    commitWrite();
  }
  function writeTypeAndLength(type, length) {
    if (length < 24) {
      writeUint8(type << 5 | length);
    } else if (length < 0x100) {
      writeUint8(type << 5 | 24);
      writeUint8(length);
    } else if (length < 0x10000) {
      writeUint8(type << 5 | 25);
      writeUint16(length);
    } else if (length < 0x100000000) {
      writeUint8(type << 5 | 26);
      writeUint32(length);
    } else {
      writeUint8(type << 5 | 27);
      writeUint64(length);
    }
  }

  function encodeItem(value) {
    var i;

    if (value === false)
      return writeUint8(0xf4);
    if (value === true)
      return writeUint8(0xf5);
    if (value === null)
      return writeUint8(0xf6);
    if (value === undefined)
      return writeUint8(0xf7);

    switch (typeof value) {
      case "number":
        if (Math.floor(value) === value) {
          if (0 <= value && value <= POW_2_53)
            return writeTypeAndLength(0, value);
          if (-POW_2_53 <= value && value < 0)
            return writeTypeAndLength(1, -(value + 1));
        }
        writeUint8(0xfb);
        return writeFloat64(value);

      case "string":
        var utf8data = [];
        for (i = 0; i < value.length; ++i) {
          var charCode = value.charCodeAt(i);
          if (charCode < 0x80) {
            utf8data.push(charCode);
          } else if (charCode < 0x800) {
            utf8data.push(0xc0 | charCode >> 6);
            utf8data.push(0x80 | charCode & 0x3f);
          } else if (charCode < 0xd800) {
            utf8data.push(0xe0 | charCode >> 12);
            utf8data.push(0x80 | (charCode >> 6)  & 0x3f);
            utf8data.push(0x80 | charCode & 0x3f);
          } else {
            charCode = (charCode & 0x3ff) << 10;
            charCode |= value.charCodeAt(++i) & 0x3ff;
            charCode += 0x10000;

            utf8data.push(0xf0 | charCode >> 18);
            utf8data.push(0x80 | (charCode >> 12)  & 0x3f);
            utf8data.push(0x80 | (charCode >> 6)  & 0x3f);
            utf8data.push(0x80 | charCode & 0x3f);
          }
        }

        writeTypeAndLength(3, utf8data.length);
        return writeUint8Array(utf8data);

      default:
        var length;
        if (Array.isArray(value)) {
          length = value.length;
          writeTypeAndLength(4, length);
          for (i = 0; i < length; ++i)
            encodeItem(value[i]);
        } else if (value instanceof Uint8Array) {
          writeTypeAndLength(2, value.length);
          writeUint8Array(value);
        } else {
          var keys = Object.keys(value);
          length = keys.length;
          writeTypeAndLength(5, length);
          for (i = 0; i < length; ++i) {
            var key = keys[i];
            encodeItem(key);
            encodeItem(value[key]);
          }
        }
    }
  }

  encodeItem(value);

  if ("slice" in data)
    return data.slice(0, offset);

  var ret = new ArrayBuffer(offset);
  var retView = new DataView(ret);
  for (var i = 0; i < offset; ++i)
    retView.setUint8(i, dataView.getUint8(i));
  return ret;
}

function decode(data, tagger, simpleValue) {
  var dataView = new DataView(data);
  var offset = 0;

  if (typeof tagger !== "function")
    tagger = function(value) { return value; };
  if (typeof simpleValue !== "function")
    simpleValue = function() { return undefined; };

  function commitRead(length, value) {
    offset += length;
    return value;
  }
  function readArrayBuffer(length) {
    return commitRead(length, new Uint8Array(data, offset, length));
  }
  function readFloat16() {
    var tempArrayBuffer = new ArrayBuffer(4);
    var tempDataView = new DataView(tempArrayBuffer);
    var value = readUint16();

    var sign = value & 0x8000;
    var exponent = value & 0x7c00;
    var fraction = value & 0x03ff;

    if (exponent === 0x7c00)
      exponent = 0xff << 10;
    else if (exponent !== 0)
      exponent += (127 - 15) << 10;
    else if (fraction !== 0)
      return (sign ? -1 : 1) * fraction * POW_2_24;

    tempDataView.setUint32(0, sign << 16 | exponent << 13 | fraction << 13);
    return tempDataView.getFloat32(0);
  }
  function readFloat32() {
    return commitRead(4, dataView.getFloat32(offset));
  }
  function readFloat64() {
    return commitRead(8, dataView.getFloat64(offset));
  }
  function readUint8() {
    return commitRead(1, dataView.getUint8(offset));
  }
  function readUint16() {
    return commitRead(2, dataView.getUint16(offset));
  }
  function readUint32() {
    return commitRead(4, dataView.getUint32(offset));
  }
  function readUint64() {
    return readUint32() * POW_2_32 + readUint32();
  }
  function readBreak() {
    if (dataView.getUint8(offset) !== 0xff)
      return false;
    offset += 1;
    return true;
  }
  function readLength(additionalInformation) {
    if (additionalInformation < 24)
      return additionalInformation;
    if (additionalInformation === 24)
      return readUint8();
    if (additionalInformation === 25)
      return readUint16();
    if (additionalInformation === 26)
      return readUint32();
    if (additionalInformation === 27)
      return readUint64();
    if (additionalInformation === 31)
      return -1;
    throw "Invalid length encoding";
  }
  function readIndefiniteStringLength(majorType) {
    var initialByte = readUint8();
    if (initialByte === 0xff)
      return -1;
    var length = readLength(initialByte & 0x1f);
    if (length < 0 || (initialByte >> 5) !== majorType)
      throw "Invalid indefinite length element";
    return length;
  }

  function appendUtf16Data(utf16data, length) {
    for (var i = 0; i < length; ++i) {
      var value = readUint8();
      if (value & 0x80) {
        if (value < 0xe0) {
          value = (value & 0x1f) <<  6
                | (readUint8() & 0x3f);
          length -= 1;
        } else if (value < 0xf0) {
          value = (value & 0x0f) << 12
                | (readUint8() & 0x3f) << 6
                | (readUint8() & 0x3f);
          length -= 2;
        } else {
          value = (value & 0x0f) << 18
                | (readUint8() & 0x3f) << 12
                | (readUint8() & 0x3f) << 6
                | (readUint8() & 0x3f);
          length -= 3;
        }
      }

      if (value < 0x10000) {
        utf16data.push(value);
      } else {
        value -= 0x10000;
        utf16data.push(0xd800 | (value >> 10));
        utf16data.push(0xdc00 | (value & 0x3ff));
      }
    }
  }

  function decodeItem() {
    var initialByte = readUint8();
    var majorType = initialByte >> 5;
    var additionalInformation = initialByte & 0x1f;
    var i;
    var length;

    if (majorType === 7) {
      switch (additionalInformation) {
        case 25:
          return readFloat16();
        case 26:
          return readFloat32();
        case 27:
          return readFloat64();
      }
    }

    length = readLength(additionalInformation);
    if (length < 0 && (majorType < 2 || 6 < majorType))
      throw "Invalid length";

    switch (majorType) {
      case 0:
        return length;
      case 1:
        return -1 - length;
      case 2:
        if (length < 0) {
          var elements = [];
          var fullArrayLength = 0;
          while ((length = readIndefiniteStringLength(majorType)) >= 0) {
            fullArrayLength += length;
            elements.push(readArrayBuffer(length));
          }
          var fullArray = new Uint8Array(fullArrayLength);
          var fullArrayOffset = 0;
          for (i = 0; i < elements.length; ++i) {
            fullArray.set(elements[i], fullArrayOffset);
            fullArrayOffset += elements[i].length;
          }
          return fullArray;
        }
        return readArrayBuffer(length);
      case 3:
        var utf16data = [];
        if (length < 0) {
          while ((length = readIndefiniteStringLength(majorType)) >= 0)
            appendUtf16Data(utf16data, length);
        } else
          appendUtf16Data(utf16data, length);
        return String.fromCharCode.apply(null, utf16data);
      case 4:
        var retArray;
        if (length < 0) {
          retArray = [];
          while (!readBreak())
            retArray.push(decodeItem());
        } else {
          retArray = new Array(length);
          for (i = 0; i < length; ++i)
            retArray[i] = decodeItem();
        }
        return retArray;
      case 5:
        var retObject = {};
        for (i = 0; i < length || length < 0 && !readBreak(); ++i) {
          var key = decodeItem();
          retObject[key] = decodeItem();
        }
        return retObject;
      case 6:
        return tagger(decodeItem(), length);
      case 7:
        switch (length) {
          case 20:
            return false;
          case 21:
            return true;
          case 22:
            return null;
          case 23:
            return undefined;
          default:
            return simpleValue(length);
        }
    }
  }

  var ret = decodeItem();
  if (offset !== data.byteLength)
    throw "Remaining bytes";
  return ret;
}

var obj = { encode: encode, decode: decode };

if (typeof define === "function" && define.amd)
  define("cbor/cbor", obj);
else if (typeof module !== "undefined" && module.exports)
  module.exports = obj;
else if (!global.CBOR)
  global.CBOR = obj;

})(this);