public:

static inline Local<ArrayBuffer> CreateTrackedArrayBuffer(

Environment* env,

char* data,

size_t length,

FreeCallback callback,

void* hint);

CallbackInfo(const CallbackInfo&) = delete;

CallbackInfo& operator=(const CallbackInfo&) = delete;

private:

static void CleanupHook(void* data);

inline void OnBackingStoreFree();

inline void CallAndResetCallback();

inline CallbackInfo(Environment* env,

FreeCallback callback,

char* data,

void* hint);

Global<ArrayBuffer> persistent_;

Mutex mutex_; // Protects callback_.

FreeCallback callback_;

char* const data_;

void* const hint_;

Environment* const env_;

Environment* env,

char* data,

size_t length,

FreeCallback callback,

void* hint) {

CHECK_NOT_NULL(callback);

CHECK_IMPLIES(data == nullptr, length == 0);

CallbackInfo* self = new CallbackInfo(env, callback, data, hint);

std::unique_ptr<BackingStore> bs =

ArrayBuffer::NewBackingStore(data, length, [](void*, size_t, void* arg) {

static_cast<CallbackInfo*>(arg)->OnBackingStoreFree();

}, self);

Local<ArrayBuffer> ab = ArrayBuffer::New(env->isolate(), std::move(bs));

// V8 simply ignores the BackingStore deleter callback if data == nullptr,

// but our API contract requires it being called.

if (data == nullptr) {

ab->Detach(Local<Value>()).Check();

self->OnBackingStoreFree(); // This calls `callback` asynchronously.

} else {

// Store the ArrayBuffer so that we can detach it later.

self->persistent_.Reset(env->isolate(), ab);

self->persistent_.SetWeak();

}

return ab;

FreeCallback callback,

char* data,

void* hint)

: callback_(callback),

data_(data),

hint_(hint),

env_(env) {

env->AddCleanupHook(CleanupHook, this);

env->isolate()->AdjustAmountOfExternalAllocatedMemory(sizeof(*this));

CallbackInfo* self = static_cast<CallbackInfo*>(data);

{

HandleScope handle_scope(self->env_->isolate());

Local<ArrayBuffer> ab = self->persistent_.Get(self->env_->isolate());

if (!ab.IsEmpty() && ab->IsDetachable()) {

ab->Detach(Local<Value>()).Check();

self->persistent_.Reset();

}

}

// Call the callback in this case, but don't delete `this` yet because the

// BackingStore deleter callback will do so later.

self->CallAndResetCallback();

FreeCallback callback;

{

Mutex::ScopedLock lock(mutex_);

callback = callback_;

callback_ = nullptr;

}

if (callback != nullptr) {

// Clean up all Environment-related state and run the callback.

env_->RemoveCleanupHook(CleanupHook, this);

int64_t change_in_bytes = -static_cast<int64_t>(sizeof(*this));

env_->isolate()->AdjustAmountOfExternalAllocatedMemory(change_in_bytes);

callback(data_, hint_);

}

// This method should always release the memory for `this`.

std::unique_ptr<CallbackInfo> self { this };

Mutex::ScopedLock lock(mutex_);

// If callback_ == nullptr, that means that the callback has already run from

// the cleanup hook, and there is nothing left to do here besides to clean

// up the memory involved. In particular, the underlying `Environment` may

// be gone at this point, so don’t attempt to call SetImmediateThreadsafe().

if (callback_ == nullptr) return;

env_->SetImmediateThreadsafe([self = std::move(self)](Environment* env) {

CHECK_EQ(self->env_, env); // Consistency check.

self->CallAndResetCallback();

});

CHECK(val->IsArrayBufferView());

Local<ArrayBufferView> ui = val.As<ArrayBufferView>();

return ui->ByteLength();

CHECK(obj->IsArrayBufferView());

Local<ArrayBufferView> ui = obj.As<ArrayBufferView>();

return ui->ByteLength();

Local<ArrayBuffer> ab,

size_t byte_offset,

size_t length) {

CHECK(!env->buffer_prototype_object().IsEmpty());

Local<Uint8Array> ui = Uint8Array::New(ab, byte_offset, length);

Maybe<bool> mb =

ui->SetPrototype(env->context(), env->buffer_prototype_object());

if (mb.IsNothing())

return MaybeLocal<Uint8Array>();

return ui;

Local<ArrayBuffer> ab,

size_t byte_offset,

size_t length) {

Environment* env = Environment::GetCurrent(isolate);

if (env == nullptr) {

THROW_ERR_BUFFER_CONTEXT_NOT_AVAILABLE(isolate);

return MaybeLocal<Uint8Array>();

}

return New(env, ab, byte_offset, length);

Local<String> string,

enum encoding enc) {

EscapableHandleScope scope(isolate);

size_t length;

if (!StringBytes::Size(isolate, string, enc).To(&length))

return Local<Object>();

size_t actual = 0;

std::unique_ptr<BackingStore> store;

if (length > 0) {

store = ArrayBuffer::NewBackingStore(isolate, length);

if (UNLIKELY(!store)) {

THROW_ERR_MEMORY_ALLOCATION_FAILED(isolate);

return Local<Object>();

}

actual = StringBytes::Write(

isolate,

static_cast<char*>(store->Data()),

length,

string,

enc);

CHECK(actual <= length);

if (LIKELY(actual > 0)) {

if (actual < length)

store = BackingStore::Reallocate(isolate, std::move(store), actual);

Local<ArrayBuffer> buf = ArrayBuffer::New(isolate, std::move(store));

Local<Object> obj;

if (UNLIKELY(!New(isolate, buf, 0, actual).ToLocal(&obj)))

return MaybeLocal<Object>();

return scope.Escape(obj);

}

}

return scope.EscapeMaybe(New(isolate, 0));

EscapableHandleScope handle_scope(isolate);

Local<Object> obj;

Environment* env = Environment::GetCurrent(isolate);

if (env == nullptr) {

THROW_ERR_BUFFER_CONTEXT_NOT_AVAILABLE(isolate);

return MaybeLocal<Object>();

}

if (Buffer::New(env, length).ToLocal(&obj))

return handle_scope.Escape(obj);

return Local<Object>();

Isolate* isolate(env->isolate());

EscapableHandleScope scope(isolate);

// V8 currently only allows a maximum Typed Array index of max Smi.

if (length > kMaxLength) {

isolate->ThrowException(ERR_BUFFER_TOO_LARGE(isolate));

return Local<Object>();

}

Local<ArrayBuffer> ab;

{

NoArrayBufferZeroFillScope no_zero_fill_scope(env->isolate_data());

std::unique_ptr<BackingStore> bs =

ArrayBuffer::NewBackingStore(isolate, length);

CHECK(bs);

ab = ArrayBuffer::New(isolate, std::move(bs));

}

MaybeLocal<Object> obj =

New(env, ab, 0, ab->ByteLength())

.FromMaybe(Local<Uint8Array>());

return scope.EscapeMaybe(obj);

EscapableHandleScope handle_scope(isolate);

Environment* env = Environment::GetCurrent(isolate);

if (env == nullptr) {

THROW_ERR_BUFFER_CONTEXT_NOT_AVAILABLE(isolate);

return MaybeLocal<Object>();

}

Local<Object> obj;

if (Buffer::Copy(env, data, length).ToLocal(&obj))

return handle_scope.Escape(obj);

return Local<Object>();

Isolate* isolate(env->isolate());

EscapableHandleScope scope(isolate);

// V8 currently only allows a maximum Typed Array index of max Smi.

if (length > kMaxLength) {

isolate->ThrowException(ERR_BUFFER_TOO_LARGE(isolate));

return Local<Object>();

}

Local<ArrayBuffer> ab;

{

NoArrayBufferZeroFillScope no_zero_fill_scope(env->isolate_data());

std::unique_ptr<BackingStore> bs =

ArrayBuffer::NewBackingStore(isolate, length);

CHECK(bs);

memcpy(bs->Data(), data, length);

ab = ArrayBuffer::New(isolate, std::move(bs));

}

MaybeLocal<Object> obj =

New(env, ab, 0, ab->ByteLength())

.FromMaybe(Local<Uint8Array>());

return scope.EscapeMaybe(obj);

char* data,

size_t length,

FreeCallback callback,

void* hint) {

EscapableHandleScope handle_scope(isolate);

Environment* env = Environment::GetCurrent(isolate);

if (env == nullptr) {

callback(data, hint);

THROW_ERR_BUFFER_CONTEXT_NOT_AVAILABLE(isolate);

return MaybeLocal<Object>();

}

return handle_scope.EscapeMaybe(

Buffer::New(env, data, length, callback, hint));

char* data,

size_t length,

FreeCallback callback,

void* hint) {

EscapableHandleScope scope(env->isolate());

if (length > kMaxLength) {

env->isolate()->ThrowException(ERR_BUFFER_TOO_LARGE(env->isolate()));

callback(data, hint);

return Local<Object>();

}

Local<ArrayBuffer> ab =

CallbackInfo::CreateTrackedArrayBuffer(env, data, length, callback, hint);

if (ab->SetPrivate(env->context(),

env->untransferable_object_private_symbol(),

True(env->isolate())).IsNothing()) {

return Local<Object>();

}

MaybeLocal<Uint8Array> maybe_ui = Buffer::New(env, ab, 0, length);

Local<Uint8Array> ui;

if (!maybe_ui.ToLocal(&ui))

return MaybeLocal<Object>();

return scope.Escape(ui);

EscapableHandleScope handle_scope(isolate);

Environment* env = Environment::GetCurrent(isolate);

if (env == nullptr) {

free(data);

THROW_ERR_BUFFER_CONTEXT_NOT_AVAILABLE(isolate);

return MaybeLocal<Object>();

}

Local<Object> obj;

if (Buffer::New(env, data, length).ToLocal(&obj))

return handle_scope.Escape(obj);

return Local<Object>();

char* data,

size_t length) {

if (length > 0) {

CHECK_NOT_NULL(data);

// V8 currently only allows a maximum Typed Array index of max Smi.

if (length > kMaxLength) {

Isolate* isolate(env->isolate());

isolate->ThrowException(ERR_BUFFER_TOO_LARGE(isolate));

free(data);

return Local<Object>();

}

}

EscapableHandleScope handle_scope(env->isolate());

auto free_callback = [](void* data, size_t length, void* deleter_data) {

free(data);

};

std::unique_ptr<BackingStore> bs =

v8::ArrayBuffer::NewBackingStore(data, length, free_callback, nullptr);

Local<ArrayBuffer> ab = v8::ArrayBuffer::New(env->isolate(), std::move(bs));

Local<Object> obj;

if (Buffer::New(env, ab, 0, length).ToLocal(&obj))

return handle_scope.Escape(obj);

return Local<Object>();

CHECK(args[0]->IsString());

CHECK(args[1]->IsInt32());

enum encoding enc = static_cast<enum encoding>(args[1].As<Int32>()->Value());

Local<Object> buf;

if (New(args.GetIsolate(), args[0].As<String>(), enc).ToLocal(&buf))

args.GetReturnValue().Set(buf);

Environment* env = Environment::GetCurrent(args);

Isolate* isolate = env->isolate();

THROW_AND_RETURN_UNLESS_BUFFER(env, args.This());

ArrayBufferViewContents<char> buffer(args.This());

if (buffer.length() == 0)

return args.GetReturnValue().SetEmptyString();

size_t start = 0;

size_t end = 0;

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[0], 0, &start));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[1], buffer.length(), &end));

if (end < start) end = start;

THROW_AND_RETURN_IF_OOB(Just(end <= buffer.length()));

size_t length = end - start;

Local<Value> error;

MaybeLocal<Value> maybe_ret =

StringBytes::Encode(isolate,

buffer.data() + start,

length,

encoding,

&error);

Local<Value> ret;

if (!maybe_ret.ToLocal(&ret)) {

CHECK(!error.IsEmpty());

isolate->ThrowException(error);

return;

}

args.GetReturnValue().Set(ret);

Environment* env = Environment::GetCurrent(args);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[1]);

ArrayBufferViewContents<char> source(args[0]);

Local<Object> target_obj = args[1].As<Object>();

SPREAD_BUFFER_ARG(target_obj, target);

size_t target_start = 0;

size_t source_start = 0;

size_t source_end = 0;

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[2], 0, &target_start));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[3], 0, &source_start));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[4], source.length(),

&source_end));

// Copy 0 bytes; we're done

if (target_start >= target_length || source_start >= source_end)

return args.GetReturnValue().Set(0);

if (source_start > source.length())

return THROW_ERR_OUT_OF_RANGE(

env, "The value of \"sourceStart\" is out of range.");

if (source_end - source_start > target_length - target_start)

source_end = source_start + target_length - target_start;

uint32_t to_copy = std::min(

std::min(source_end - source_start, target_length - target_start),

source.length() - source_start);

memmove(target_data + target_start, source.data() + source_start, to_copy);

args.GetReturnValue().Set(to_copy);

Environment* env = Environment::GetCurrent(args);

Local<Context> ctx = env->context();

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

SPREAD_BUFFER_ARG(args[0], ts_obj);

size_t start = 0;

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[2], 0, &start));

size_t end;

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[3], 0, &end));

size_t fill_length = end - start;

Local<String> str_obj;

size_t str_length;

enum encoding enc;

// OOB Check. Throw the error in JS.

if (start > end || fill_length + start > ts_obj_length)

return args.GetReturnValue().Set(-2);

// First check if Buffer has been passed.

if (Buffer::HasInstance(args[1])) {

SPREAD_BUFFER_ARG(args[1], fill_obj);

str_length = fill_obj_length;

memcpy(

ts_obj_data + start, fill_obj_data, std::min(str_length, fill_length));

goto start_fill;

}

// Then coerce everything that's not a string.

if (!args[1]->IsString()) {

uint32_t val;

if (!args[1]->Uint32Value(ctx).To(&val)) return;

int value = val & 255;

memset(ts_obj_data + start, value, fill_length);

return;

}

str_obj = args[1]->ToString(env->context()).ToLocalChecked();

enc = ParseEncoding(env->isolate(), args[4], UTF8);

// Can't use StringBytes::Write() in all cases. For example if attempting

// to write a two byte character into a one byte Buffer.

if (enc == UTF8) {

str_length = str_obj->Utf8Length(env->isolate());

node::Utf8Value str(env->isolate(), args[1]);

memcpy(ts_obj_data + start, *str, std::min(str_length, fill_length));

} else if (enc == UCS2) {

str_length = str_obj->Length() * sizeof(uint16_t);

node::TwoByteValue str(env->isolate(), args[1]);

if (IsBigEndian())

SwapBytes16(reinterpret_cast<char*>(&str[0]), str_length);

memcpy(ts_obj_data + start, *str, std::min(str_length, fill_length));

} else {

// Write initial String to Buffer, then use that memory to copy remainder

// of string. Correct the string length for cases like HEX where less than

// the total string length is written.

str_length = StringBytes::Write(

env->isolate(), ts_obj_data + start, fill_length, str_obj, enc);

}

start_fill:

if (str_length >= fill_length)

return;

// If str_length is zero, then either an empty buffer was provided, or Write()

// indicated that no bytes could be written. If no bytes could be written,

// then return -1 because the fill value is invalid. This will trigger a throw

// in JavaScript. Silently failing should be avoided because it can lead to

// buffers with unexpected contents.

if (str_length == 0)

return args.GetReturnValue().Set(-1);

size_t in_there = str_length;

char* ptr = ts_obj_data + start + str_length;

while (in_there < fill_length - in_there) {

memcpy(ptr, ts_obj_data + start, in_there);

ptr += in_there;

in_there *= 2;

}

if (in_there < fill_length) {

memcpy(ptr, ts_obj_data + start, fill_length - in_there);

}

Environment* env = Environment::GetCurrent(args);

THROW_AND_RETURN_UNLESS_BUFFER(env, args.This());

SPREAD_BUFFER_ARG(args.This(), ts_obj);

THROW_AND_RETURN_IF_NOT_STRING(env, args[0], "argument");

Local<String> str = args[0]->ToString(env->context()).ToLocalChecked();

size_t offset = 0;

size_t max_length = 0;

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[1], 0, &offset));

if (offset > ts_obj_length) {

return node::THROW_ERR_BUFFER_OUT_OF_BOUNDS(

env, "\"offset\" is outside of buffer bounds");

}

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[2], ts_obj_length - offset,

&max_length));

max_length = std::min(ts_obj_length - offset, max_length);

if (max_length == 0)

return args.GetReturnValue().Set(0);

uint32_t written = StringBytes::Write(

env->isolate(), ts_obj_data + offset, max_length, str, encoding);

args.GetReturnValue().Set(written);

Environment* env = Environment::GetCurrent(args);

CHECK(args[0]->IsString());

// Fast case: avoid StringBytes on UTF8 string. Jump to v8.

args.GetReturnValue().Set(args[0].As<String>()->Utf8Length(env->isolate()));

const v8::FastOneByteString& source) {

uint32_t result = 0;

uint32_t length = source.length;

const uint8_t* data = reinterpret_cast<const uint8_t*>(source.data);

for (uint32_t i = 0; i < length; ++i) {

result += (data[i] >> 7);

}

result += length;

return result;

if (val == 0) {

if (a_length > b_length)

return 1;

else if (a_length < b_length)

return -1;

} else {

if (val > 0)

return 1;

else

return -1;

}

return val;

Environment* env = Environment::GetCurrent(args);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[1]);

ArrayBufferViewContents<char> source(args[0]);

ArrayBufferViewContents<char> target(args[1]);

size_t target_start = 0;

size_t source_start = 0;

size_t source_end = 0;

size_t target_end = 0;

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[2], 0, &target_start));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[3], 0, &source_start));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[4], target.length(),

&target_end));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(env, args[5], source.length(),

&source_end));

if (source_start > source.length())

return THROW_ERR_OUT_OF_RANGE(

env, "The value of \"sourceStart\" is out of range.");

if (target_start > target.length())

return THROW_ERR_OUT_OF_RANGE(

env, "The value of \"targetStart\" is out of range.");

CHECK_LE(source_start, source_end);

CHECK_LE(target_start, target_end);

size_t to_cmp =

std::min(std::min(source_end - source_start, target_end - target_start),

source.length() - source_start);

int val = normalizeCompareVal(to_cmp > 0 ?

memcmp(source.data() + source_start,

target.data() + target_start,

to_cmp) : 0,

source_end - source_start,

target_end - target_start);

args.GetReturnValue().Set(val);

Environment* env = Environment::GetCurrent(args);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[1]);

ArrayBufferViewContents<char> a(args[0]);

ArrayBufferViewContents<char> b(args[1]);

size_t cmp_length = std::min(a.length(), b.length());

int val = normalizeCompareVal(cmp_length > 0 ?

memcmp(a.data(), b.data(), cmp_length) : 0,

a.length(), b.length());

args.GetReturnValue().Set(val);

int64_t offset_i64,

int64_t needle_length,

bool is_forward) {

int64_t length_i64 = static_cast<int64_t>(length);

if (offset_i64 < 0) {

if (offset_i64 + length_i64 >= 0) {

// Negative offsets count backwards from the end of the buffer.

return length_i64 + offset_i64;

} else if (is_forward || needle_length == 0) {

// indexOf from before the start of the buffer: search the whole buffer.

return 0;

} else {

// lastIndexOf from before the start of the buffer: no match.

return -1;

}

} else {

if (offset_i64 + needle_length <= length_i64) {

// Valid positive offset.

return offset_i64;

} else if (needle_length == 0) {

// Out of buffer bounds, but empty needle: point to end of buffer.

return length_i64;

} else if (is_forward) {

// indexOf from past the end of the buffer: no match.

return -1;

} else {

// lastIndexOf from past the end of the buffer: search the whole buffer.

return length_i64 - 1;

}

}

Environment* env = Environment::GetCurrent(args);

Isolate* isolate = env->isolate();

CHECK(args[1]->IsString());

CHECK(args[2]->IsNumber());

CHECK(args[3]->IsInt32());

CHECK(args[4]->IsBoolean());

enum encoding enc = static_cast<enum encoding>(args[3].As<Int32>()->Value());

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

ArrayBufferViewContents<char> buffer(args[0]);

Local<String> needle = args[1].As<String>();

int64_t offset_i64 = args[2].As<Integer>()->Value();

bool is_forward = args[4]->IsTrue();

const char* haystack = buffer.data();

// Round down to the nearest multiple of 2 in case of UCS2.

const size_t haystack_length = (enc == UCS2) ?

buffer.length() &~ 1 : buffer.length(); // NOLINT(whitespace/operators)

size_t needle_length;

if (!StringBytes::Size(isolate, needle, enc).To(&needle_length)) return;

int64_t opt_offset = IndexOfOffset(haystack_length,

offset_i64,

needle_length,

is_forward);

if (needle_length == 0) {

// Match String#indexOf() and String#lastIndexOf() behavior.

args.GetReturnValue().Set(static_cast<double>(opt_offset));

return;

}

if (haystack_length == 0) {

return args.GetReturnValue().Set(-1);

}

if (opt_offset <= -1) {

return args.GetReturnValue().Set(-1);

}

size_t offset = static_cast<size_t>(opt_offset);

CHECK_LT(offset, haystack_length);

if ((is_forward && needle_length + offset > haystack_length) ||

needle_length > haystack_length) {

return args.GetReturnValue().Set(-1);

}

size_t result = haystack_length;

if (enc == UCS2) {

String::Value needle_value(isolate, needle);

if (*needle_value == nullptr)

return args.GetReturnValue().Set(-1);

if (haystack_length < 2 || needle_value.length() < 1) {

return args.GetReturnValue().Set(-1);

}

if (IsBigEndian()) {

StringBytes::InlineDecoder decoder;

if (decoder.Decode(env, needle, enc).IsNothing()) return;

const uint16_t* decoded_string =

reinterpret_cast<const uint16_t*>(decoder.out());

if (decoded_string == nullptr)

return args.GetReturnValue().Set(-1);

result = SearchString(reinterpret_cast<const uint16_t*>(haystack),

haystack_length / 2,

decoded_string,

decoder.size() / 2,

offset / 2,

is_forward);

} else {

result = SearchString(reinterpret_cast<const uint16_t*>(haystack),

haystack_length / 2,

reinterpret_cast<const uint16_t*>(*needle_value),

needle_value.length(),

offset / 2,

is_forward);

}

result *= 2;

} else if (enc == UTF8) {

String::Utf8Value needle_value(isolate, needle);

if (*needle_value == nullptr)

return args.GetReturnValue().Set(-1);

result = SearchString(reinterpret_cast<const uint8_t*>(haystack),

haystack_length,

reinterpret_cast<const uint8_t*>(*needle_value),

needle_length,

offset,

is_forward);

} else if (enc == LATIN1) {

uint8_t* needle_data = node::UncheckedMalloc<uint8_t>(needle_length);

if (needle_data == nullptr) {

return args.GetReturnValue().Set(-1);

}

needle->WriteOneByte(

isolate, needle_data, 0, needle_length, String::NO_NULL_TERMINATION);

result = SearchString(reinterpret_cast<const uint8_t*>(haystack),

haystack_length,

needle_data,

needle_length,

offset,

is_forward);

free(needle_data);

}

args.GetReturnValue().Set(

result == haystack_length ? -1 : static_cast<int>(result));

CHECK(args[1]->IsObject());

CHECK(args[2]->IsNumber());

CHECK(args[3]->IsInt32());

CHECK(args[4]->IsBoolean());

enum encoding enc = static_cast<enum encoding>(args[3].As<Int32>()->Value());

THROW_AND_RETURN_UNLESS_BUFFER(Environment::GetCurrent(args), args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(Environment::GetCurrent(args), args[1]);