src/typedarray.js

// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

(function(global, utils) {

"use strict";

%CheckIsBootstrapping();

// -------------------------------------------------------------------
// Imports

var GlobalArray = global.Array;
var GlobalArrayBuffer = global.ArrayBuffer;
var GlobalDataView = global.DataView;
var GlobalObject = global.Object;

macro TYPED_ARRAYS(FUNCTION)
// arrayIds below should be synchronized with Runtime_TypedArrayInitialize.
FUNCTION(1, Uint8Array, 1)
FUNCTION(2, Int8Array, 1)
FUNCTION(3, Uint16Array, 2)
FUNCTION(4, Int16Array, 2)
FUNCTION(5, Uint32Array, 4)
FUNCTION(6, Int32Array, 4)
FUNCTION(7, Float32Array, 4)
FUNCTION(8, Float64Array, 8)
FUNCTION(9, Uint8ClampedArray, 1)
endmacro

macro DECLARE_GLOBALS(INDEX, NAME, SIZE)
var GlobalNAME = global.NAME;
endmacro

TYPED_ARRAYS(DECLARE_GLOBALS)

var MathMax;
var MathMin;

utils.Import(function(from) {
  MathMax = from.MathMax;
  MathMin = from.MathMin;
});

var InternalArray = utils.InternalArray;

// --------------- Typed Arrays ---------------------

macro TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME, ELEMENT_SIZE)
function NAMEConstructByArrayBuffer(obj, buffer, byteOffset, length) {
  if (!IS_UNDEFINED(byteOffset)) {
      byteOffset =
          $toPositiveInteger(byteOffset, kInvalidTypedArrayLength);
  }
  if (!IS_UNDEFINED(length)) {
      length = $toPositiveInteger(length, kInvalidTypedArrayLength);
  }

  var bufferByteLength = %_ArrayBufferGetByteLength(buffer);
  var offset;
  if (IS_UNDEFINED(byteOffset)) {
    offset = 0;
  } else {
    offset = byteOffset;

    if (offset % ELEMENT_SIZE !== 0) {
      throw MakeRangeError(kInvalidTypedArrayAlignment,
                           "start offset", "NAME", ELEMENT_SIZE);
    }
    if (offset > bufferByteLength) {
      throw MakeRangeError(kInvalidTypedArrayOffset);
    }
  }

  var newByteLength;
  var newLength;
  if (IS_UNDEFINED(length)) {
    if (bufferByteLength % ELEMENT_SIZE !== 0) {
      throw MakeRangeError(kInvalidTypedArrayAlignment,
                           "byte length", "NAME", ELEMENT_SIZE);
    }
    newByteLength = bufferByteLength - offset;
    newLength = newByteLength / ELEMENT_SIZE;
  } else {
    var newLength = length;
    newByteLength = newLength * ELEMENT_SIZE;
  }
  if ((offset + newByteLength > bufferByteLength)
      || (newLength > %_MaxSmi())) {
    throw MakeRangeError(kInvalidTypedArrayLength);
  }
  %_TypedArrayInitialize(obj, ARRAY_ID, buffer, offset, newByteLength, true);
}

function NAMEConstructByLength(obj, length) {
  var l = IS_UNDEFINED(length) ?
    0 : $toPositiveInteger(length, kInvalidTypedArrayLength);
  if (l > %_MaxSmi()) {
    throw MakeRangeError(kInvalidTypedArrayLength);
  }
  var byteLength = l * ELEMENT_SIZE;
  if (byteLength > %_TypedArrayMaxSizeInHeap()) {
    var buffer = new GlobalArrayBuffer(byteLength);
    %_TypedArrayInitialize(obj, ARRAY_ID, buffer, 0, byteLength, true);
  } else {
    %_TypedArrayInitialize(obj, ARRAY_ID, null, 0, byteLength, true);
  }
}

function NAMEConstructByArrayLike(obj, arrayLike) {
  var length = arrayLike.length;
  var l = $toPositiveInteger(length, kInvalidTypedArrayLength);

  if (l > %_MaxSmi()) {
    throw MakeRangeError(kInvalidTypedArrayLength);
  }
  var initialized = false;
  var byteLength = l * ELEMENT_SIZE;
  if (byteLength <= %_TypedArrayMaxSizeInHeap()) {
    %_TypedArrayInitialize(obj, ARRAY_ID, null, 0, byteLength, false);
  } else {
    initialized =
        %TypedArrayInitializeFromArrayLike(obj, ARRAY_ID, arrayLike, l);
  }
  if (!initialized) {
    for (var i = 0; i < l; i++) {
      // It is crucial that we let any execptions from arrayLike[i]
      // propagate outside the function.
      obj[i] = arrayLike[i];
    }
  }
}

function NAMEConstructByIterable(obj, iterable, iteratorFn) {
  var list = new InternalArray();
  // Reading the Symbol.iterator property of iterable twice would be
  // observable with getters, so instead, we call the function which
  // was already looked up, and wrap it in another iterable. The
  // __proto__ of the new iterable is set to null to avoid any chance
  // of modifications to Object.prototype being observable here.
  var iterator = %_CallFunction(iterable, iteratorFn);
  var newIterable = {
    __proto__: null
  };
  // TODO(littledan): Computed properties don't work yet in nosnap.
  // Rephrase when they do.
  newIterable[symbolIterator] = function() { return iterator; }
  for (var value of newIterable) {
    list.push(value);
  }
  NAMEConstructByArrayLike(obj, list);
}

function NAMEConstructor(arg1, arg2, arg3) {
  if (%_IsConstructCall()) {
    if (IS_ARRAYBUFFER(arg1) || IS_SHAREDARRAYBUFFER(arg1)) {
      NAMEConstructByArrayBuffer(this, arg1, arg2, arg3);
    } else if (IS_NUMBER(arg1) || IS_STRING(arg1) ||
               IS_BOOLEAN(arg1) || IS_UNDEFINED(arg1)) {
      NAMEConstructByLength(this, arg1);
    } else {
      var iteratorFn = arg1[symbolIterator];
      if (IS_UNDEFINED(iteratorFn) || iteratorFn === $arrayValues) {
        NAMEConstructByArrayLike(this, arg1);
      } else {
        NAMEConstructByIterable(this, arg1, iteratorFn);
      }
    }
  } else {
    throw MakeTypeError(kConstructorNotFunction, "NAME")
  }
}

function NAME_GetBuffer() {
  if (!(%_ClassOf(this) === 'NAME')) {
    throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.buffer", this);
  }
  return %TypedArrayGetBuffer(this);
}

function NAME_GetByteLength() {
  if (!(%_ClassOf(this) === 'NAME')) {
    throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.byteLength", this);
  }
  return %_ArrayBufferViewGetByteLength(this);
}

function NAME_GetByteOffset() {
  if (!(%_ClassOf(this) === 'NAME')) {
    throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.byteOffset", this);
  }
  return %_ArrayBufferViewGetByteOffset(this);
}

function NAME_GetLength() {
  if (!(%_ClassOf(this) === 'NAME')) {
    throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.length", this);
  }
  return %_TypedArrayGetLength(this);
}

function NAMESubArray(begin, end) {
  if (!(%_ClassOf(this) === 'NAME')) {
    throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.subarray", this);
  }
  var beginInt = TO_INTEGER(begin);
  if (!IS_UNDEFINED(end)) {
    end = TO_INTEGER(end);
  }

  var srcLength = %_TypedArrayGetLength(this);
  if (beginInt < 0) {
    beginInt = MathMax(0, srcLength + beginInt);
  } else {
    beginInt = MathMin(srcLength, beginInt);
  }

  var endInt = IS_UNDEFINED(end) ? srcLength : end;
  if (endInt < 0) {
    endInt = MathMax(0, srcLength + endInt);
  } else {
    endInt = MathMin(endInt, srcLength);
  }
  if (endInt < beginInt) {
    endInt = beginInt;
  }
  var newLength = endInt - beginInt;
  var beginByteOffset =
      %_ArrayBufferViewGetByteOffset(this) + beginInt * ELEMENT_SIZE;
  return new GlobalNAME(%TypedArrayGetBuffer(this),
                        beginByteOffset, newLength);
}
endmacro

TYPED_ARRAYS(TYPED_ARRAY_CONSTRUCTOR)


function TypedArraySetFromArrayLike(target, source, sourceLength, offset) {
  if (offset > 0) {
    for (var i = 0; i < sourceLength; i++) {
      target[offset + i] = source[i];
    }
  }
  else {
    for (var i = 0; i < sourceLength; i++) {
      target[i] = source[i];
    }
  }
}

function TypedArraySetFromOverlappingTypedArray(target, source, offset) {
  var sourceElementSize = source.BYTES_PER_ELEMENT;
  var targetElementSize = target.BYTES_PER_ELEMENT;
  var sourceLength = source.length;

  // Copy left part.
  function CopyLeftPart() {
    // First un-mutated byte after the next write
    var targetPtr = target.byteOffset + (offset + 1) * targetElementSize;
    // Next read at sourcePtr. We do not care for memory changing before
    // sourcePtr - we have already copied it.
    var sourcePtr = source.byteOffset;
    for (var leftIndex = 0;
         leftIndex < sourceLength && targetPtr <= sourcePtr;
         leftIndex++) {
      target[offset + leftIndex] = source[leftIndex];
      targetPtr += targetElementSize;
      sourcePtr += sourceElementSize;
    }
    return leftIndex;
  }
  var leftIndex = CopyLeftPart();

  // Copy rigth part;
  function CopyRightPart() {
    // First unmutated byte before the next write
    var targetPtr =
      target.byteOffset + (offset + sourceLength - 1) * targetElementSize;
    // Next read before sourcePtr. We do not care for memory changing after
    // sourcePtr - we have already copied it.
    var sourcePtr =
      source.byteOffset + sourceLength * sourceElementSize;
    for(var rightIndex = sourceLength - 1;
        rightIndex >= leftIndex && targetPtr >= sourcePtr;
        rightIndex--) {
      target[offset + rightIndex] = source[rightIndex];
      targetPtr -= targetElementSize;
      sourcePtr -= sourceElementSize;
    }
    return rightIndex;
  }
  var rightIndex = CopyRightPart();

  var temp = new GlobalArray(rightIndex + 1 - leftIndex);
  for (var i = leftIndex; i <= rightIndex; i++) {
    temp[i - leftIndex] = source[i];
  }
  for (i = leftIndex; i <= rightIndex; i++) {
    target[offset + i] = temp[i - leftIndex];
  }
}

function TypedArraySet(obj, offset) {
  var intOffset = IS_UNDEFINED(offset) ? 0 : TO_INTEGER(offset);
  if (intOffset < 0) throw MakeTypeError(kTypedArraySetNegativeOffset);

  if (intOffset > %_MaxSmi()) {
    throw MakeRangeError(kTypedArraySetSourceTooLarge);
  }
  switch (%TypedArraySetFastCases(this, obj, intOffset)) {
    // These numbers should be synchronized with runtime.cc.
    case 0: // TYPED_ARRAY_SET_TYPED_ARRAY_SAME_TYPE
      return;
    case 1: // TYPED_ARRAY_SET_TYPED_ARRAY_OVERLAPPING
      TypedArraySetFromOverlappingTypedArray(this, obj, intOffset);
      return;
    case 2: // TYPED_ARRAY_SET_TYPED_ARRAY_NONOVERLAPPING
      TypedArraySetFromArrayLike(this, obj, obj.length, intOffset);
      return;
    case 3: // TYPED_ARRAY_SET_NON_TYPED_ARRAY
      var l = obj.length;
      if (IS_UNDEFINED(l)) {
        if (IS_NUMBER(obj)) {
            // For number as a first argument, throw TypeError
            // instead of silently ignoring the call, so that
            // the user knows (s)he did something wrong.
            // (Consistent with Firefox and Blink/WebKit)
            throw MakeTypeError(kInvalidArgument);
        }
        return;
      }
      if (intOffset + l > this.length) {
        throw MakeRangeError(kTypedArraySetSourceTooLarge);
      }
      TypedArraySetFromArrayLike(this, obj, l, intOffset);
      return;
  }
}

function TypedArrayGetToStringTag() {
  if (!%_IsTypedArray(this)) return;
  var name = %_ClassOf(this);
  if (IS_UNDEFINED(name)) return;
  return name;
}

// -------------------------------------------------------------------

macro SETUP_TYPED_ARRAY(ARRAY_ID, NAME, ELEMENT_SIZE)
  %SetCode(GlobalNAME, NAMEConstructor);
  %FunctionSetPrototype(GlobalNAME, new GlobalObject());

  %AddNamedProperty(GlobalNAME, "BYTES_PER_ELEMENT", ELEMENT_SIZE,
                    READ_ONLY | DONT_ENUM | DONT_DELETE);
  %AddNamedProperty(GlobalNAME.prototype,
                    "constructor", global.NAME, DONT_ENUM);
  %AddNamedProperty(GlobalNAME.prototype,
                    "BYTES_PER_ELEMENT", ELEMENT_SIZE,
                    READ_ONLY | DONT_ENUM | DONT_DELETE);
  utils.InstallGetter(GlobalNAME.prototype, "buffer", NAME_GetBuffer);
  utils.InstallGetter(GlobalNAME.prototype, "byteOffset", NAME_GetByteOffset,
                      DONT_ENUM | DONT_DELETE);
  utils.InstallGetter(GlobalNAME.prototype, "byteLength", NAME_GetByteLength,
                      DONT_ENUM | DONT_DELETE);
  utils.InstallGetter(GlobalNAME.prototype, "length", NAME_GetLength,
                      DONT_ENUM | DONT_DELETE);
  utils.InstallGetter(GlobalNAME.prototype, symbolToStringTag,
                      TypedArrayGetToStringTag);
  utils.InstallFunctions(GlobalNAME.prototype, DONT_ENUM, [
    "subarray", NAMESubArray,
    "set", TypedArraySet
  ]);
endmacro

TYPED_ARRAYS(SETUP_TYPED_ARRAY)

// --------------------------- DataView -----------------------------

function DataViewConstructor(buffer, byteOffset, byteLength) { // length = 3
  if (%_IsConstructCall()) {
    // TODO(binji): support SharedArrayBuffers?
    if (!IS_ARRAYBUFFER(buffer)) throw MakeTypeError(kDataViewNotArrayBuffer);
    if (!IS_UNDEFINED(byteOffset)) {
        byteOffset = $toPositiveInteger(byteOffset, kInvalidDataViewOffset);
    }
    if (!IS_UNDEFINED(byteLength)) {
        byteLength = TO_INTEGER(byteLength);
    }

    var bufferByteLength = %_ArrayBufferGetByteLength(buffer);

    var offset = IS_UNDEFINED(byteOffset) ?  0 : byteOffset;
    if (offset > bufferByteLength) throw MakeRangeError(kInvalidDataViewOffset);

    var length = IS_UNDEFINED(byteLength)
        ? bufferByteLength - offset
        : byteLength;
    if (length < 0 || offset + length > bufferByteLength) {
      throw new MakeRangeError(kInvalidDataViewLength);
    }
    %_DataViewInitialize(this, buffer, offset, length);
  } else {
    throw MakeTypeError(kConstructorNotFunction, "DataView");
  }
}

function DataViewGetBufferJS() {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError(kIncompatibleMethodReceiver, 'DataView.buffer', this);
  }
  return %DataViewGetBuffer(this);
}

function DataViewGetByteOffset() {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError(kIncompatibleMethodReceiver,
                        'DataView.byteOffset', this);
  }
  return %_ArrayBufferViewGetByteOffset(this);
}

function DataViewGetByteLength() {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError(kIncompatibleMethodReceiver,
                        'DataView.byteLength', this);
  }
  return %_ArrayBufferViewGetByteLength(this);
}

macro DATA_VIEW_TYPES(FUNCTION)
  FUNCTION(Int8)
  FUNCTION(Uint8)
  FUNCTION(Int16)
  FUNCTION(Uint16)
  FUNCTION(Int32)
  FUNCTION(Uint32)
  FUNCTION(Float32)
  FUNCTION(Float64)
endmacro


macro DATA_VIEW_GETTER_SETTER(TYPENAME)
function DataViewGetTYPENAMEJS(offset, little_endian) {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError(kIncompatibleMethodReceiver,
                        'DataView.getTYPENAME', this);
  }
  if (%_ArgumentsLength() < 1) throw MakeTypeError(kInvalidArgument);
  offset = $toPositiveInteger(offset, kInvalidDataViewAccessorOffset);
  return %DataViewGetTYPENAME(this, offset, !!little_endian);
}

function DataViewSetTYPENAMEJS(offset, value, little_endian) {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError(kIncompatibleMethodReceiver,
                        'DataView.setTYPENAME', this);
  }
  if (%_ArgumentsLength() < 2) throw MakeTypeError(kInvalidArgument);
  offset = $toPositiveInteger(offset, kInvalidDataViewAccessorOffset);
  %DataViewSetTYPENAME(this, offset, TO_NUMBER_INLINE(value), !!little_endian);
}
endmacro

DATA_VIEW_TYPES(DATA_VIEW_GETTER_SETTER)

// Setup the DataView constructor.
%SetCode(GlobalDataView, DataViewConstructor);
%FunctionSetPrototype(GlobalDataView, new GlobalObject);

// Set up constructor property on the DataView prototype.
%AddNamedProperty(GlobalDataView.prototype, "constructor", GlobalDataView,
                  DONT_ENUM);
%AddNamedProperty(GlobalDataView.prototype, symbolToStringTag, "DataView",
                  READ_ONLY|DONT_ENUM);

utils.InstallGetter(GlobalDataView.prototype, "buffer", DataViewGetBufferJS);
utils.InstallGetter(GlobalDataView.prototype, "byteOffset",
                    DataViewGetByteOffset);
utils.InstallGetter(GlobalDataView.prototype, "byteLength",
                    DataViewGetByteLength);

utils.InstallFunctions(GlobalDataView.prototype, DONT_ENUM, [
  "getInt8", DataViewGetInt8JS,
  "setInt8", DataViewSetInt8JS,

  "getUint8", DataViewGetUint8JS,
  "setUint8", DataViewSetUint8JS,

  "getInt16", DataViewGetInt16JS,
  "setInt16", DataViewSetInt16JS,

  "getUint16", DataViewGetUint16JS,
  "setUint16", DataViewSetUint16JS,

  "getInt32", DataViewGetInt32JS,
  "setInt32", DataViewSetInt32JS,

  "getUint32", DataViewGetUint32JS,
  "setUint32", DataViewSetUint32JS,

  "getFloat32", DataViewGetFloat32JS,
  "setFloat32", DataViewSetFloat32JS,

  "getFloat64", DataViewGetFloat64JS,
  "setFloat64", DataViewSetFloat64JS
]);

})