Merge commit '6e92d2345e8231a44556ce7d416451f5f3e6c398' as 'engine262'

2026-08-18 13:21:55 +00:00 · 2026-03-27 10:07:29 +05:30
parent 8f26db5a1f 6e92d2345e
commit b42a69d9f8
433 changed files with 90478 additions and 0 deletions
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+import { Q } from '../completion.mts';
+import { __ts_cast__ } from '../helpers.mts';
+import type { DataViewObject } from '../intrinsics/DataView.mts';
+import { type TypedArrayTypes, typedArrayInfoByType } from '../intrinsics/TypedArray.mts';
+import { Value } from '../value.mts';
+import {
+  Assert,
+  GetValueFromBuffer,
+  IsDetachedBuffer,
+  IsBigIntElementType,
+  SetValueInBuffer,
+  ToBoolean,
+  ToIndex,
+  ToNumber,
+  ToBigInt,
+  RequireInternalSlot,
+  type ArrayBufferObject,
+  ArrayBufferByteLength,
+  IsFixedLengthArrayBuffer,
+} from './all.mts';
+import { Throw } from '#self';
+
+// This file covers abstract operations defined in
+/** https://tc39.es/ecma262/#sec-dataview-objects */
+
+/** https://tc39.es/ecma262/#sec-dataview-with-buffer-witness-records */
+export interface DataViewWithBufferWitnessRecord {
+  readonly Object: DataViewObject;
+  CachedBufferByteLength: number | 'detached';
+}
+
+/** https://tc39.es/ecma262/#sec-makedataviewwithbufferwitnessrecord */
+export function MakeDataViewWithBufferWitnessRecord(obj: DataViewObject, order: 'seq-cst' | 'unordered'): DataViewWithBufferWitnessRecord {
+  const buffer = obj.ViewedArrayBuffer as ArrayBufferObject;
+  let byteLength: DataViewWithBufferWitnessRecord['CachedBufferByteLength'];
+  if (IsDetachedBuffer(buffer)) {
+    byteLength = 'detached';
+  } else {
+    byteLength = ArrayBufferByteLength(buffer, order);
+  }
+  return { Object: obj, CachedBufferByteLength: byteLength };
+}
+
+/** https://tc39.es/ecma262/#sec-getviewbytelength */
+export function GetViewByteLength(viewRecord: DataViewWithBufferWitnessRecord): number {
+  Assert(!IsViewOutOfBounds(viewRecord));
+  const view = viewRecord.Object;
+  // @ts-expect-error
+  if (view.ByteLength !== 'auto') {
+    return view.ByteLength;
+  }
+  Assert(!IsFixedLengthArrayBuffer(view.ViewedArrayBuffer as ArrayBufferObject));
+  const byteOffset = view.ByteOffset;
+  const byteLength = viewRecord.CachedBufferByteLength;
+  Assert(byteLength !== 'detached');
+  return byteLength - byteOffset;
+}
+
+/** https://tc39.es/ecma262/#sec-isviewoutofbounds */
+export function IsViewOutOfBounds(viewRecord: DataViewWithBufferWitnessRecord): boolean {
+  const view = viewRecord.Object;
+  const bufferByteLength = viewRecord.CachedBufferByteLength;
+  if (IsDetachedBuffer(view.ViewedArrayBuffer as ArrayBufferObject)) {
+    Assert(bufferByteLength === 'detached');
+    return true;
+  }
+  Assert(typeof bufferByteLength === 'number' && bufferByteLength >= 0);
+  const byteOffsetStart = view.ByteOffset;
+  let byteOffsetEnd;
+  // @ts-expect-error
+  if (view.ByteLength === 'auto') {
+    byteOffsetEnd = bufferByteLength;
+  } else {
+    byteOffsetEnd = byteOffsetStart + view.ByteLength;
+  }
+  if (byteOffsetStart > bufferByteLength || byteOffsetEnd > bufferByteLength) {
+    return true;
+  }
+  return false;
+}
+
+/** https://tc39.es/ecma262/#sec-getviewvalue */
+export function* GetViewValue(view: Value, requestIndex: Value, isLittleEndian: Value, type: TypedArrayTypes) {
+  // 1. Perform ? RequireInternalSlot(view, [[DataView]]).
+  Q(RequireInternalSlot(view, 'DataView'));
+  __ts_cast__<DataViewObject>(view);
+  // 2. Assert: view has a [[ViewedArrayBuffer]] internal slot.
+  Assert('ViewedArrayBuffer' in view);
+  // 3. Let getIndex be ? ToIndex(requestIndex).
+  const getIndex = Q(yield* ToIndex(requestIndex));
+  // 4. Set isLittleEndian to ToBoolean(isLittleEndian).
+  isLittleEndian = ToBoolean(isLittleEndian);
+  // 7. Let viewOffset be view.[[ByteOffset]].
+  const viewOffset = view.ByteOffset;
+  const viewRecord = MakeDataViewWithBufferWitnessRecord(view, 'unordered');
+  if (IsViewOutOfBounds(viewRecord)) {
+    return Throw.TypeError('Offset is out of bound');
+  }
+  const viewSize = GetViewByteLength(viewRecord);
+  // 9. Let elementSize be the Element Size value specified in Table 61 for Element Type type.
+  const elementSize = typedArrayInfoByType[type].ElementSize;
+  // 10. If getIndex + elementSize > viewSize, throw a RangeError exception.
+  if (getIndex + elementSize > viewSize) {
+    return Throw.RangeError('Offset is out of bound');
+  }
+  // 11. Let bufferIndex be getIndex + viewOffset.
+  const bufferIndex = getIndex + viewOffset;
+  // 12. Return GetValueFromBuffer(buffer, bufferIndex, type, false, Unordered, isLittleEndian).
+  return GetValueFromBuffer(view.ViewedArrayBuffer as ArrayBufferObject, bufferIndex, type, false, 'unordered', isLittleEndian.booleanValue());
+}
+
+/** https://tc39.es/ecma262/#sec-setviewvalue */
+export function* SetViewValue(view: Value, requestIndex: Value, isLittleEndian: Value, type: TypedArrayTypes, value: Value) {
+  // 1. Perform ? RequireInternalSlot(view, [[DataView]]).
+  Q(RequireInternalSlot(view, 'DataView'));
+  // 2. Assert: view has a [[ViewedArrayBuffer]] internal slot.
+  Assert('ViewedArrayBuffer' in view);
+  __ts_cast__<DataViewObject>(view);
+  // 3. Let getIndex be ? ToIndex(requestIndex).
+  const getIndex = Q(yield* ToIndex(requestIndex));
+  // 4. If IsBigIntElementType(type) is true, let numberValue be ? ToBigInt(value).
+  // 5. Otherwise, let numberValue be ? ToNumber(value).
+  let numberValue;
+  if (IsBigIntElementType(type) === Value.true) {
+    numberValue = Q(yield* ToBigInt(value));
+  } else {
+    numberValue = Q(yield* ToNumber(value));
+  }
+  // 6. Set isLittleEndian to ToBoolean(isLittleEndian).
+  isLittleEndian = ToBoolean(isLittleEndian);
+  // 9. Let viewOffset be view.[[ByteOffset]].
+  const viewOffset = view.ByteOffset;
+  const viewRecord = MakeDataViewWithBufferWitnessRecord(view, 'unordered');
+  if (IsViewOutOfBounds(viewRecord)) {
+    return Throw.TypeError('Offset is out of bound');
+  }
+  const viewSize = GetViewByteLength(viewRecord);
+  // 11. Let elementSize be the Element Size value specified in Table 61 for Element Type type.
+  const elementSize = typedArrayInfoByType[type].ElementSize;
+  // 12. If getIndex + elementSize > viewSize, throw a RangeError exception.
+  if (getIndex + elementSize > viewSize) {
+    return Throw.RangeError('Offset is out of bound');
+  }
+  // 13. Let bufferIndex be getIndex + viewOffset.
+  const bufferIndex = getIndex + viewOffset;
+  // 14. Perform ? SetValueInBuffer(buffer, bufferIndex, type, numberValue, false, Unordered, isLittleEndian).
+  Q(yield* SetValueInBuffer(view.ViewedArrayBuffer as ArrayBufferObject, bufferIndex, type, numberValue, false, 'unordered', isLittleEndian.booleanValue()));
+  return Value.undefined;
+}