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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef vm_TypedArrayObject_h
#define vm_TypedArrayObject_h
#include "mozilla/Maybe.h"
#include "mozilla/TextUtils.h"
#include "gc/Barrier.h"
#include "gc/MaybeRooted.h"
#include "js/Class.h"
#include "js/experimental/TypedData.h" // js::detail::TypedArrayLengthSlot
#include "js/Result.h"
#include "js/ScalarType.h" // js::Scalar::Type
#include "vm/ArrayBufferObject.h"
#include "vm/ArrayBufferViewObject.h"
#include "vm/JSObject.h"
#include "vm/SharedArrayObject.h"
MACRO(int8_t, Int8) \
MACRO(uint8_t, Uint8) \
MACRO(int16_t, Int16) \
MACRO(uint16_t, Uint16) \
MACRO(int32_t, Int32) \
MACRO(uint32_t, Uint32) \
MACRO(float, Float32) \
MACRO(double, Float64) \
MACRO(uint8_clamped, Uint8Clamped) \
MACRO(int64_t, BigInt64) \
MACRO(uint64_t, BigUint64)
namespace js {
* TypedArrayObject
* The non-templated base class for the specific typed implementations.
* This class holds all the member variables that are used by
* the subclasses.
class TypedArrayObject : public ArrayBufferViewObject {
static_assert(js::detail::TypedArrayLengthSlot == LENGTH_SLOT,
"bad inlined constant in TypedData.h");
static bool sameBuffer(Handle<TypedArrayObject*> a,
Handle<TypedArrayObject*> b) {
// Inline buffers.
if (!a->hasBuffer() || !b->hasBuffer()) {
return a.get() == b.get();
// Shared buffers.
if (a->isSharedMemory() && b->isSharedMemory()) {
return a->bufferShared()->globalID() == b->bufferShared()->globalID();
return a->bufferEither() == b->bufferEither();
static const JSClass classes[Scalar::MaxTypedArrayViewType];
static const JSClass protoClasses[Scalar::MaxTypedArrayViewType];
static const JSClass sharedTypedArrayPrototypeClass;
static const JSClass* classForType(Scalar::Type type) {
MOZ_ASSERT(type < Scalar::MaxTypedArrayViewType);
return &classes[type];
static const JSClass* protoClassForType(Scalar::Type type) {
MOZ_ASSERT(type < Scalar::MaxTypedArrayViewType);
return &protoClasses[type];
static constexpr size_t FIXED_DATA_START = DATA_SLOT + 1;
// For typed arrays which can store their data inline, the array buffer
// object is created lazily.
static constexpr uint32_t INLINE_BUFFER_LIMIT =
(NativeObject::MAX_FIXED_SLOTS - FIXED_DATA_START) * sizeof(Value);
static inline gc::AllocKind AllocKindForLazyBuffer(size_t nbytes);
inline Scalar::Type type() const;
inline size_t bytesPerElement() const;
static bool ensureHasBuffer(JSContext* cx, Handle<TypedArrayObject*> tarray);
BufferSize byteLength() const {
return BufferSize(length().get() * bytesPerElement());
BufferSize length() const {
return BufferSize(size_t(getFixedSlot(LENGTH_SLOT).toPrivate()));
Value byteLengthValue() const {
size_t len = byteLength().get();
return NumberValue(len);
Value lengthValue() const {
size_t len = length().get();
return NumberValue(len);
bool hasInlineElements() const;
void setInlineElements();
uint8_t* elementsRaw() const {
return *(uint8_t**)((((char*)this) + ArrayBufferViewObject::dataOffset()));
uint8_t* elements() const {
return elementsRaw();
#ifdef DEBUG
void assertZeroLengthArrayData() const;
void assertZeroLengthArrayData() const {};
template <AllowGC allowGC>
bool getElement(JSContext* cx, size_t index,
typename MaybeRooted<Value, allowGC>::MutableHandleType val);
bool getElementPure(size_t index, Value* vp);
* Copy all elements from this typed array to vp. vp must point to rooted
* memory.
static bool getElements(JSContext* cx, Handle<TypedArrayObject*> tarray,
Value* vp);
static bool GetTemplateObjectForNative(JSContext* cx, Native native,
const JS::HandleValueArray args,
MutableHandleObject res);
* Maximum allowed byte length for any typed array.
static size_t maxByteLength() {
return ArrayBufferObject::maxBufferByteLength();
static bool isOriginalLengthGetter(Native native);
static bool isOriginalByteOffsetGetter(Native native);
static bool isOriginalByteLengthGetter(Native native);
static void finalize(JSFreeOp* fop, JSObject* obj);
static size_t objectMoved(JSObject* obj, JSObject* old);
/* Initialization bits */
static const JSFunctionSpec protoFunctions[];
static const JSPropertySpec protoAccessors[];
static const JSFunctionSpec staticFunctions[];
static const JSPropertySpec staticProperties[];
/* Accessors and functions */
static bool is(HandleValue v);
static bool set(JSContext* cx, unsigned argc, Value* vp);
static bool copyWithin(JSContext* cx, unsigned argc, Value* vp);
bool convertForSideEffect(JSContext* cx, HandleValue v) const;
static bool set_impl(JSContext* cx, const CallArgs& args);
static bool copyWithin_impl(JSContext* cx, const CallArgs& args);
[[nodiscard]] bool TypedArray_bufferGetter(JSContext* cx, unsigned argc,
Value* vp);
extern TypedArrayObject* NewTypedArrayWithTemplateAndLength(
JSContext* cx, HandleObject templateObj, int32_t len);
extern TypedArrayObject* NewTypedArrayWithTemplateAndArray(
JSContext* cx, HandleObject templateObj, HandleObject array);
extern TypedArrayObject* NewTypedArrayWithTemplateAndBuffer(
JSContext* cx, HandleObject templateObj, HandleObject arrayBuffer,
HandleValue byteOffset, HandleValue length);
inline bool IsTypedArrayClass(const JSClass* clasp) {
return &TypedArrayObject::classes[0] <= clasp &&
clasp < &TypedArrayObject::classes[Scalar::MaxTypedArrayViewType];
inline Scalar::Type GetTypedArrayClassType(const JSClass* clasp) {
return static_cast<Scalar::Type>(clasp - &TypedArrayObject::classes[0]);
bool IsTypedArrayConstructor(const JSObject* obj);
bool IsTypedArrayConstructor(HandleValue v, Scalar::Type type);
JSNative TypedArrayConstructorNative(Scalar::Type type);
// In WebIDL terminology, a BufferSource is either an ArrayBuffer or a typed
// array view. In either case, extract the dataPointer/byteLength.
bool IsBufferSource(JSObject* object, SharedMem<uint8_t*>* dataPointer,
size_t* byteLength);
inline Scalar::Type TypedArrayObject::type() const {
return GetTypedArrayClassType(getClass());
inline size_t TypedArrayObject::bytesPerElement() const {
return Scalar::byteSize(type());
// ES2020 draft rev a5375bdad264c8aa264d9c44f57408087761069e
// 7.1.16 CanonicalNumericIndexString
// Checks whether or not the string is a canonical numeric index string. If the
// string is a canonical numeric index which is not representable as a uint64_t,
// the returned index is UINT64_MAX.
template <typename CharT>
[[nodiscard]] bool StringToTypedArrayIndex(JSContext* cx,
mozilla::Range<const CharT> s,
mozilla::Maybe<uint64_t>* indexp);
// A string |s| is a TypedArray index (or: canonical numeric index string) iff
// |s| is "-0" or |SameValue(ToString(ToNumber(s)), s)| is true. So check for
// any characters which can start the string representation of a number,
// including "NaN" and "Infinity".
template <typename CharT>
inline bool CanStartTypedArrayIndex(CharT ch) {
return mozilla::IsAsciiDigit(ch) || ch == '-' || ch == 'N' || ch == 'I';
[[nodiscard]] inline bool ToTypedArrayIndex(JSContext* cx, jsid id,
mozilla::Maybe<uint64_t>* indexp) {
if (JSID_IS_INT(id)) {
int32_t i = JSID_TO_INT(id);
MOZ_ASSERT(i >= 0);
return true;
return true;
JS::AutoCheckCannotGC nogc;
JSAtom* atom = JSID_TO_ATOM(id);
if (atom->empty() || !CanStartTypedArrayIndex(atom->latin1OrTwoByteChar(0))) {
return true;
if (atom->hasLatin1Chars()) {
mozilla::Range<const Latin1Char> chars = atom->latin1Range(nogc);
return StringToTypedArrayIndex(cx, chars, indexp);
mozilla::Range<const char16_t> chars = atom->twoByteRange(nogc);
return StringToTypedArrayIndex(cx, chars, indexp);
bool SetTypedArrayElement(JSContext* cx, Handle<TypedArrayObject*> obj,
uint64_t index, HandleValue v,
ObjectOpResult& result);
* Implements [[DefineOwnProperty]] for TypedArrays when the property
* key is a TypedArray index.
bool DefineTypedArrayElement(JSContext* cx, Handle<TypedArrayObject*> obj,
uint64_t index, Handle<PropertyDescriptor> desc,
ObjectOpResult& result);
static inline constexpr unsigned TypedArrayShift(Scalar::Type viewType) {
switch (viewType) {
case Scalar::Int8:
case Scalar::Uint8:
case Scalar::Uint8Clamped:
return 0;
case Scalar::Int16:
case Scalar::Uint16:
return 1;
case Scalar::Int32:
case Scalar::Uint32:
case Scalar::Float32:
return 2;
case Scalar::BigInt64:
case Scalar::BigUint64:
case Scalar::Int64:
case Scalar::Float64:
return 3;
MOZ_CRASH("Unexpected array type");
static inline constexpr unsigned TypedArrayElemSize(Scalar::Type viewType) {
return 1u << TypedArrayShift(viewType);
} // namespace js
template <>
inline bool JSObject::is<js::TypedArrayObject>() const {
return js::IsTypedArrayClass(getClass());
#endif /* vm_TypedArrayObject_h */