array-buffer.js

'use strict';
var global = require('../internals/global');
var DESCRIPTORS = require('../internals/descriptors');
var NATIVE_ARRAY_BUFFER = require('../internals/array-buffer-native');
var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
var redefineAll = require('../internals/redefine-all');
var fails = require('../internals/fails');
var anInstance = require('../internals/an-instance');
var toInteger = require('../internals/to-integer');
var toLength = require('../internals/to-length');
var toIndex = require('../internals/to-index');
var IEEE754 = require('../internals/ieee754');
var getPrototypeOf = require('../internals/object-get-prototype-of');
var setPrototypeOf = require('../internals/object-set-prototype-of');
var getOwnPropertyNames = require('../internals/object-get-own-property-names').f;
var defineProperty = require('../internals/object-define-property').f;
var arrayFill = require('../internals/array-fill');
var setToStringTag = require('../internals/set-to-string-tag');
var InternalStateModule = require('../internals/internal-state');

var getInternalState = InternalStateModule.get;
var setInternalState = InternalStateModule.set;
var ARRAY_BUFFER = 'ArrayBuffer';
var DATA_VIEW = 'DataView';
var PROTOTYPE = 'prototype';
var WRONG_LENGTH = 'Wrong length';
var WRONG_INDEX = 'Wrong index';
var NativeArrayBuffer = global[ARRAY_BUFFER];
var $ArrayBuffer = NativeArrayBuffer;
var $DataView = global[DATA_VIEW];
var $DataViewPrototype = $DataView && $DataView[PROTOTYPE];
var ObjectPrototype = Object.prototype;
var RangeError = global.RangeError;

var packIEEE754 = IEEE754.pack;
var unpackIEEE754 = IEEE754.unpack;

var packInt8 = function (number) {
  return [number & 0xFF];
};

var packInt16 = function (number) {
  return [number & 0xFF, number >> 8 & 0xFF];
};

var packInt32 = function (number) {
  return [number & 0xFF, number >> 8 & 0xFF, number >> 16 & 0xFF, number >> 24 & 0xFF];
};

var unpackInt32 = function (buffer) {
  return buffer[3] << 24 | buffer[2] << 16 | buffer[1] << 8 | buffer[0];
};

var packFloat32 = function (number) {
  return packIEEE754(number, 23, 4);
};

var packFloat64 = function (number) {
  return packIEEE754(number, 52, 8);
};

var addGetter = function (Constructor, key) {
  defineProperty(Constructor[PROTOTYPE], key, { get: function () { return getInternalState(this)[key]; } });
};

var get = function (view, count, index, isLittleEndian) {
  var intIndex = toIndex(index);
  var store = getInternalState(view);
  if (intIndex + count > store.byteLength) throw RangeError(WRONG_INDEX);
  var bytes = getInternalState(store.buffer).bytes;
  var start = intIndex + store.byteOffset;
  var pack = bytes.slice(start, start + count);
  return isLittleEndian ? pack : pack.reverse();
};

var set = function (view, count, index, conversion, value, isLittleEndian) {
  var intIndex = toIndex(index);
  var store = getInternalState(view);
  if (intIndex + count > store.byteLength) throw RangeError(WRONG_INDEX);
  var bytes = getInternalState(store.buffer).bytes;
  var start = intIndex + store.byteOffset;
  var pack = conversion(+value);
  for (var i = 0; i < count; i++) bytes[start + i] = pack[isLittleEndian ? i : count - i - 1];
};

if (!NATIVE_ARRAY_BUFFER) {
  $ArrayBuffer = function ArrayBuffer(length) {
    anInstance(this, $ArrayBuffer, ARRAY_BUFFER);
    var byteLength = toIndex(length);
    setInternalState(this, {
      bytes: arrayFill.call(new Array(byteLength), 0),
      byteLength: byteLength
    });
    if (!DESCRIPTORS) this.byteLength = byteLength;
  };

  $DataView = function DataView(buffer, byteOffset, byteLength) {
    anInstance(this, $DataView, DATA_VIEW);
    anInstance(buffer, $ArrayBuffer, DATA_VIEW);
    var bufferLength = getInternalState(buffer).byteLength;
    var offset = toInteger(byteOffset);
    if (offset < 0 || offset > bufferLength) throw RangeError('Wrong offset');
    byteLength = byteLength === undefined ? bufferLength - offset : toLength(byteLength);
    if (offset + byteLength > bufferLength) throw RangeError(WRONG_LENGTH);
    setInternalState(this, {
      buffer: buffer,
      byteLength: byteLength,
      byteOffset: offset
    });
    if (!DESCRIPTORS) {
      this.buffer = buffer;
      this.byteLength = byteLength;
      this.byteOffset = offset;
    }
  };

  if (DESCRIPTORS) {
    addGetter($ArrayBuffer, 'byteLength');
    addGetter($DataView, 'buffer');
    addGetter($DataView, 'byteLength');
    addGetter($DataView, 'byteOffset');
  }

  redefineAll($DataView[PROTOTYPE], {
    getInt8: function getInt8(byteOffset) {
      return get(this, 1, byteOffset)[0] << 24 >> 24;
    },
    getUint8: function getUint8(byteOffset) {
      return get(this, 1, byteOffset)[0];
    },
    getInt16: function getInt16(byteOffset /* , littleEndian */) {
      var bytes = get(this, 2, byteOffset, arguments.length > 1 ? arguments[1] : undefined);
      return (bytes[1] << 8 | bytes[0]) << 16 >> 16;
    },
    getUint16: function getUint16(byteOffset /* , littleEndian */) {
      var bytes = get(this, 2, byteOffset, arguments.length > 1 ? arguments[1] : undefined);
      return bytes[1] << 8 | bytes[0];
    },
    getInt32: function getInt32(byteOffset /* , littleEndian */) {
      return unpackInt32(get(this, 4, byteOffset, arguments.length > 1 ? arguments[1] : undefined));
    },
    getUint32: function getUint32(byteOffset /* , littleEndian */) {
      return unpackInt32(get(this, 4, byteOffset, arguments.length > 1 ? arguments[1] : undefined)) >>> 0;
    },
    getFloat32: function getFloat32(byteOffset /* , littleEndian */) {
      return unpackIEEE754(get(this, 4, byteOffset, arguments.length > 1 ? arguments[1] : undefined), 23);
    },
    getFloat64: function getFloat64(byteOffset /* , littleEndian */) {
      return unpackIEEE754(get(this, 8, byteOffset, arguments.length > 1 ? arguments[1] : undefined), 52);
    },
    setInt8: function setInt8(byteOffset, value) {
      set(this, 1, byteOffset, packInt8, value);
    },
    setUint8: function setUint8(byteOffset, value) {
      set(this, 1, byteOffset, packInt8, value);
    },
    setInt16: function setInt16(byteOffset, value /* , littleEndian */) {
      set(this, 2, byteOffset, packInt16, value, arguments.length > 2 ? arguments[2] : undefined);
    },
    setUint16: function setUint16(byteOffset, value /* , littleEndian */) {
      set(this, 2, byteOffset, packInt16, value, arguments.length > 2 ? arguments[2] : undefined);
    },
    setInt32: function setInt32(byteOffset, value /* , littleEndian */) {
      set(this, 4, byteOffset, packInt32, value, arguments.length > 2 ? arguments[2] : undefined);
    },
    setUint32: function setUint32(byteOffset, value /* , littleEndian */) {
      set(this, 4, byteOffset, packInt32, value, arguments.length > 2 ? arguments[2] : undefined);
    },
    setFloat32: function setFloat32(byteOffset, value /* , littleEndian */) {
      set(this, 4, byteOffset, packFloat32, value, arguments.length > 2 ? arguments[2] : undefined);
    },
    setFloat64: function setFloat64(byteOffset, value /* , littleEndian */) {
      set(this, 8, byteOffset, packFloat64, value, arguments.length > 2 ? arguments[2] : undefined);
    }
  });
} else {
  if (!fails(function () {
    NativeArrayBuffer(1);
  }) || !fails(function () {
    new NativeArrayBuffer(-1); // eslint-disable-line no-new
  }) || fails(function () {
    new NativeArrayBuffer(); // eslint-disable-line no-new
    new NativeArrayBuffer(1.5); // eslint-disable-line no-new
    new NativeArrayBuffer(NaN); // eslint-disable-line no-new
    return NativeArrayBuffer.name != ARRAY_BUFFER;
  })) {
    $ArrayBuffer = function ArrayBuffer(length) {
      anInstance(this, $ArrayBuffer);
      return new NativeArrayBuffer(toIndex(length));
    };
    var ArrayBufferPrototype = $ArrayBuffer[PROTOTYPE] = NativeArrayBuffer[PROTOTYPE];
    for (var keys = getOwnPropertyNames(NativeArrayBuffer), j = 0, key; keys.length > j;) {
      if (!((key = keys[j++]) in $ArrayBuffer)) {
        createNonEnumerableProperty($ArrayBuffer, key, NativeArrayBuffer[key]);
      }
    }
    ArrayBufferPrototype.constructor = $ArrayBuffer;
  }

  // WebKit bug - the same parent prototype for typed arrays and data view
  if (setPrototypeOf && getPrototypeOf($DataViewPrototype) !== ObjectPrototype) {
    setPrototypeOf($DataViewPrototype, ObjectPrototype);
  }

  // iOS Safari 7.x bug
  var testView = new $DataView(new $ArrayBuffer(2));
  var nativeSetInt8 = $DataViewPrototype.setInt8;
  testView.setInt8(0, 2147483648);
  testView.setInt8(1, 2147483649);
  if (testView.getInt8(0) || !testView.getInt8(1)) redefineAll($DataViewPrototype, {
    setInt8: function setInt8(byteOffset, value) {
      nativeSetInt8.call(this, byteOffset, value << 24 >> 24);
    },
    setUint8: function setUint8(byteOffset, value) {
      nativeSetInt8.call(this, byteOffset, value << 24 >> 24);
    }
  }, { unsafe: true });
}

setToStringTag($ArrayBuffer, ARRAY_BUFFER);
setToStringTag($DataView, DATA_VIEW);

module.exports = {
  ArrayBuffer: $ArrayBuffer,
  DataView: $DataView
};