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.

"use strict";

// This file relies on the fact that the following declaration has been made
// in runtime.js:
// var $Array = global.Array;
var $ArrayBuffer = global.ArrayBuffer;


// --------------- Typed Arrays ---------------------
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 TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME, ELEMENT_SIZE)
function NAMEConstructByArrayBuffer(obj, buffer, byteOffset, length) {
  if (!IS_UNDEFINED(byteOffset)) {
      byteOffset =
          ToPositiveInteger(byteOffset,  "invalid_typed_array_length");
  }
  if (!IS_UNDEFINED(length)) {
      length = ToPositiveInteger(length, "invalid_typed_array_length");
  }

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

    if (offset % ELEMENT_SIZE !== 0) {
      throw MakeRangeError("invalid_typed_array_alignment",
          ["start offset", "NAME", ELEMENT_SIZE]);
    }
    if (offset > bufferByteLength) {
      throw MakeRangeError("invalid_typed_array_offset");
    }
  }

  var newByteLength;
  var newLength;
  if (IS_UNDEFINED(length)) {
    if (bufferByteLength % ELEMENT_SIZE !== 0) {
      throw MakeRangeError("invalid_typed_array_alignment",
        ["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("invalid_typed_array_length");
  }
  %_TypedArrayInitialize(obj, ARRAY_ID, buffer, offset, newByteLength);
}

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

function NAMEConstructByArrayLike(obj, arrayLike) {
  var length = arrayLike.length;
  var l = ToPositiveInteger(length, "invalid_typed_array_length");

  if (l > %_MaxSmi()) {
    throw MakeRangeError("invalid_typed_array_length");
  }
  if(!%TypedArrayInitializeFromArrayLike(obj, ARRAY_ID, arrayLike, l)) {
    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 NAMEConstructor(arg1, arg2, arg3) {
  if (%_IsConstructCall()) {
    if (IS_ARRAYBUFFER(arg1)) {
      NAMEConstructByArrayBuffer(this, arg1, arg2, arg3);
    } else if (IS_NUMBER(arg1) || IS_STRING(arg1) ||
               IS_BOOLEAN(arg1) || IS_UNDEFINED(arg1)) {
      NAMEConstructByLength(this, arg1);
    } else {
      NAMEConstructByArrayLike(this, arg1);
    }
  } else {
    throw MakeTypeError("constructor_not_function", ["NAME"])
  }
}

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

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

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

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

var $NAME = global.NAME;

function NAMESubArray(begin, end) {
  if (!(%_ClassOf(this) === 'NAME')) {
    throw MakeTypeError('incompatible_method_receiver',
                        ["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 $NAME(%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 $Array(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("typed_array_set_negative_offset");
  }

  if (intOffset > %_MaxSmi()) {
    throw MakeRangeError("typed_array_set_source_too_large");
  }
  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("invalid_argument");
        }
        return;
      }
      if (intOffset + l > this.length) {
        throw MakeRangeError("typed_array_set_source_too_large");
      }
      TypedArraySetFromArrayLike(this, obj, l, intOffset);
      return;
  }
}

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

function SetupTypedArrays() {
macro SETUP_TYPED_ARRAY(ARRAY_ID, NAME, ELEMENT_SIZE)
  %CheckIsBootstrapping();
  %SetCode(global.NAME, NAMEConstructor);
  %FunctionSetPrototype(global.NAME, new $Object());

  %AddNamedProperty(global.NAME, "BYTES_PER_ELEMENT", ELEMENT_SIZE,
                    READ_ONLY | DONT_ENUM | DONT_DELETE);
  %AddNamedProperty(global.NAME.prototype,
                    "constructor", global.NAME, DONT_ENUM);
  %AddNamedProperty(global.NAME.prototype,
                    "BYTES_PER_ELEMENT", ELEMENT_SIZE,
                    READ_ONLY | DONT_ENUM | DONT_DELETE);
  InstallGetter(global.NAME.prototype, "buffer", NAME_GetBuffer);
  InstallGetter(global.NAME.prototype, "byteOffset", NAME_GetByteOffset);
  InstallGetter(global.NAME.prototype, "byteLength", NAME_GetByteLength);
  InstallGetter(global.NAME.prototype, "length", NAME_GetLength);

  InstallFunctions(global.NAME.prototype, DONT_ENUM, $Array(
        "subarray", NAMESubArray,
        "set", TypedArraySet
  ));
endmacro

TYPED_ARRAYS(SETUP_TYPED_ARRAY)
}

SetupTypedArrays();

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

var $DataView = global.DataView;

function DataViewConstructor(buffer, byteOffset, byteLength) { // length = 3
  if (%_IsConstructCall()) {
    if (!IS_ARRAYBUFFER(buffer)) {
      throw MakeTypeError('data_view_not_array_buffer', []);
    }
    if (!IS_UNDEFINED(byteOffset)) {
        byteOffset = ToPositiveInteger(byteOffset, 'invalid_data_view_offset');
    }
    if (!IS_UNDEFINED(byteLength)) {
        byteLength = TO_INTEGER(byteLength);
    }

    var bufferByteLength = %_ArrayBufferGetByteLength(buffer);

    var offset = IS_UNDEFINED(byteOffset) ?  0 : byteOffset;
    if (offset > bufferByteLength) {
      throw MakeRangeError('invalid_data_view_offset');
    }

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

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

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

function DataViewGetByteLength() {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError('incompatible_method_receiver',
                        ['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

function ToPositiveDataViewOffset(offset) {
  return ToPositiveInteger(offset, 'invalid_data_view_accessor_offset');
}


macro DATA_VIEW_GETTER_SETTER(TYPENAME)
function DataViewGetTYPENAMEJS(offset, little_endian) {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError('incompatible_method_receiver',
                        ['DataView.getTYPENAME', this]);
  }
  if (%_ArgumentsLength() < 1) {
    throw MakeTypeError('invalid_argument');
  }
  return %DataViewGetTYPENAME(this,
                          ToPositiveDataViewOffset(offset),
                          !!little_endian);
}

function DataViewSetTYPENAMEJS(offset, value, little_endian) {
  if (!IS_DATAVIEW(this)) {
    throw MakeTypeError('incompatible_method_receiver',
                        ['DataView.setTYPENAME', this]);
  }
  if (%_ArgumentsLength() < 2) {
    throw MakeTypeError('invalid_argument');
  }
  %DataViewSetTYPENAME(this,
                   ToPositiveDataViewOffset(offset),
                   TO_NUMBER_INLINE(value),
                   !!little_endian);
}
endmacro

DATA_VIEW_TYPES(DATA_VIEW_GETTER_SETTER)

function SetupDataView() {
  %CheckIsBootstrapping();

  // Setup the DataView constructor.
  %SetCode($DataView, DataViewConstructor);
  %FunctionSetPrototype($DataView, new $Object);

  // Set up constructor property on the DataView prototype.
  %AddNamedProperty($DataView.prototype, "constructor", $DataView, DONT_ENUM);

  InstallGetter($DataView.prototype, "buffer", DataViewGetBufferJS);
  InstallGetter($DataView.prototype, "byteOffset", DataViewGetByteOffset);
  InstallGetter($DataView.prototype, "byteLength", DataViewGetByteLength);

  InstallFunctions($DataView.prototype, DONT_ENUM, $Array(
      "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
  ));
}

SetupDataView();