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// Copyright 2019 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.
namespace typed_array {
// ES %TypedArray%.prototype.subarray
transitioning javascript builtin TypedArrayPrototypeSubArray(
js-implicit context: NativeContext,
receiver: JSAny)(...arguments): JSTypedArray {
const methodName: constexpr string = '%TypedArray%.prototype.subarray';
// 1. Let O be the this value.
// 3. If O does not have a [[TypedArrayName]] internal slot, throw a
// TypeError exception.
const source = Cast<JSTypedArray>(receiver)
otherwise ThrowTypeError(
MessageTemplate::kIncompatibleMethodReceiver, methodName);
// 5. Let buffer be O.[[ViewedArrayBuffer]].
const buffer = typed_array::GetBuffer(source);
// 6. Let srcLength be O.[[ArrayLength]].
const srcLength: uintptr = source.length;
// 7. Let relativeBegin be ? ToInteger(begin).
// 8. If relativeBegin < 0, let beginIndex be max((srcLength +
// relativeBegin), 0); else let beginIndex be min(relativeBegin,
// srcLength).
const arg0 = arguments[0];
const begin: uintptr =
arg0 != Undefined ? ConvertToRelativeIndex(arg0, srcLength) : 0;
// 9. If end is undefined, let relativeEnd be srcLength;
// else, let relativeEnd be ? ToInteger(end).
// 10. If relativeEnd < 0, let endIndex be max((srcLength + relativeEnd),
// 0); else let endIndex be min(relativeEnd, srcLength).
const arg1 = arguments[1];
const end: uintptr =
arg1 != Undefined ? ConvertToRelativeIndex(arg1, srcLength) : srcLength;
// 11. Let newLength be max(endIndex - beginIndex, 0).
const newLength: uintptr = Unsigned(IntPtrMax(Signed(end - begin), 0));
// 12. Let constructorName be the String value of O.[[TypedArrayName]].
// 13. Let elementSize be the Number value of the Element Size value
// specified in Table 52 for constructorName.
const elementsInfo = typed_array::GetTypedArrayElementsInfo(source);
// 14. Let srcByteOffset be O.[[ByteOffset]].
const srcByteOffset: uintptr = source.byte_offset;
// 15. Let beginByteOffset be srcByteOffset + beginIndex × elementSize.
const beginByteOffset =
srcByteOffset + elementsInfo.CalculateByteLength(begin)
otherwise ThrowRangeError(MessageTemplate::kInvalidArrayBufferLength);
// 16. Let argumentsList be « buffer, beginByteOffset, newLength ».
// 17. Return ? TypedArraySpeciesCreate(O, argumentsList).
return TypedArraySpeciesCreateByBuffer(
methodName, source, buffer, beginByteOffset, newLength);
}
}
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