#include "node.h"

#include "node_buffer.h"

#include "env.h"

#include "env-inl.h"

#include "string_bytes.h"

#include "string_search.h"

#include "util.h"

#include "util-inl.h"

#include "v8-profiler.h"

#include "v8.h"

#include <string.h>

#include <limits.h>

#define BUFFER_ID 0xB0E4

#define MIN(a, b) ((a) < (b) ? (a) : (b))

#define THROW_AND_RETURN_IF_OOB(r) \

do { \

if (!(r)) return env->ThrowRangeError("out of range index"); \

} while (0)

#define SLICE_START_END(start_arg, end_arg, end_max) \

size_t start; \

size_t end; \

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(start_arg, 0, &start)); \

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(end_arg, end_max, &end)); \

if (end < start) end = start; \

THROW_AND_RETURN_IF_OOB(end <= end_max); \

size_t length = end - start;

namespace node {

// if true, all Buffer and SlowBuffer instances will automatically zero-fill

bool zero_fill_all_buffers = false;

namespace {

inline void* BufferMalloc(size_t length) {

return zero_fill_all_buffers ? node::UncheckedCalloc(length) :

node::UncheckedMalloc(length);

}

} // namespace

namespace Buffer {

using v8::ArrayBuffer;

using v8::ArrayBufferCreationMode;

using v8::Context;

using v8::EscapableHandleScope;

using v8::FunctionCallbackInfo;

using v8::Integer;

using v8::Isolate;

using v8::Local;

using v8::Maybe;

using v8::MaybeLocal;

using v8::Object;

using v8::Persistent;

using v8::String;

using v8::Uint32Array;

using v8::Uint8Array;

using v8::Value;

using v8::WeakCallbackInfo;

class CallbackInfo {

public:

static inline void Free(char* data, void* hint);

static inline CallbackInfo* New(Isolate* isolate,

Local<ArrayBuffer> object,

FreeCallback callback,

char* data,

void* hint = 0);

private:

static void WeakCallback(const WeakCallbackInfo<CallbackInfo>&);

inline void WeakCallback(Isolate* isolate);

inline CallbackInfo(Isolate* isolate,

Local<ArrayBuffer> object,

FreeCallback callback,

char* data,

void* hint);

~CallbackInfo();

Persistent<ArrayBuffer> persistent_;

FreeCallback const callback_;

char* const data_;

void* const hint_;

DISALLOW_COPY_AND_ASSIGN(CallbackInfo);

};

void CallbackInfo::Free(char* data, void*) {

::free(data);

}

CallbackInfo* CallbackInfo::New(Isolate* isolate,

Local<ArrayBuffer> object,

FreeCallback callback,

char* data,

void* hint) {

return new CallbackInfo(isolate, object, callback, data, hint);

}

CallbackInfo::CallbackInfo(Isolate* isolate,

Local<ArrayBuffer> object,

FreeCallback callback,

char* data,

void* hint)

: persistent_(isolate, object),

callback_(callback),

data_(data),

hint_(hint) {

ArrayBuffer::Contents obj_c = object->GetContents();

CHECK_EQ(data_, static_cast<char*>(obj_c.Data()));

if (object->ByteLength() != 0)

CHECK_NE(data_, nullptr);

persistent_.SetWeak(this, WeakCallback, v8::WeakCallbackType::kParameter);

persistent_.SetWrapperClassId(BUFFER_ID);

persistent_.MarkIndependent();

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

}

CallbackInfo::~CallbackInfo() {

persistent_.Reset();

}

void CallbackInfo::WeakCallback(

const WeakCallbackInfo<CallbackInfo>& data) {

CallbackInfo* self = data.GetParameter();

self->WeakCallback(data.GetIsolate());

delete self;

}

void CallbackInfo::WeakCallback(Isolate* isolate) {

callback_(data_, hint_);

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

isolate->AdjustAmountOfExternalAllocatedMemory(change_in_bytes);

}

// Parse index for external array data.

inline MUST_USE_RESULT bool ParseArrayIndex(Local<Value> arg,

size_t def,

size_t* ret) {

if (arg->IsUndefined()) {

*ret = def;

return true;

}

int64_t tmp_i = arg->IntegerValue();

if (tmp_i < 0)

return false;

// Check that the result fits in a size_t.

const uint64_t kSizeMax = static_cast<uint64_t>(static_cast<size_t>(-1));

// coverity[pointless_expression]

if (static_cast<uint64_t>(tmp_i) > kSizeMax)

return false;

*ret = static_cast<size_t>(tmp_i);

return true;

}

// Buffer methods

bool HasInstance(Local<Value> val) {

return val->IsUint8Array();

}

bool HasInstance(Local<Object> obj) {

return obj->IsUint8Array();

}

char* Data(Local<Value> val) {

CHECK(val->IsUint8Array());

Local<Uint8Array> ui = val.As<Uint8Array>();

ArrayBuffer::Contents ab_c = ui->Buffer()->GetContents();

return static_cast<char*>(ab_c.Data()) + ui->ByteOffset();

}

char* Data(Local<Object> obj) {

CHECK(obj->IsUint8Array());

Local<Uint8Array> ui = obj.As<Uint8Array>();

ArrayBuffer::Contents ab_c = ui->Buffer()->GetContents();

return static_cast<char*>(ab_c.Data()) + ui->ByteOffset();

}

size_t Length(Local<Value> val) {

CHECK(val->IsUint8Array());

Local<Uint8Array> ui = val.As<Uint8Array>();

return ui->ByteLength();

}

size_t Length(Local<Object> obj) {

CHECK(obj->IsUint8Array());

Local<Uint8Array> ui = obj.As<Uint8Array>();

return ui->ByteLength();

}

MaybeLocal<Object> New(Isolate* isolate,

Local<String> string,

enum encoding enc) {

EscapableHandleScope scope(isolate);

const size_t length = StringBytes::Size(isolate, string, enc);

size_t actual = 0;

char* data = nullptr;

if (length > 0) {

data = static_cast<char*>(BufferMalloc(length));

if (data == nullptr)

return Local<Object>();

actual = StringBytes::Write(isolate, data, length, string, enc);

CHECK(actual <= length);

if (actual == 0) {

free(data);

data = nullptr;

} else if (actual < length) {

data = node::Realloc(data, actual);

}

}

Local<Object> buf;

if (New(isolate, data, actual).ToLocal(&buf))

return scope.Escape(buf);

// Object failed to be created. Clean up resources.

free(data);

return Local<Object>();

}

MaybeLocal<Object> New(Isolate* isolate, size_t length) {

EscapableHandleScope handle_scope(isolate);

Local<Object> obj;

if (Buffer::New(Environment::GetCurrent(isolate), length).ToLocal(&obj))

return handle_scope.Escape(obj);

return Local<Object>();

}

MaybeLocal<Object> New(Environment* env, size_t length) {

EscapableHandleScope scope(env->isolate());

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

if (length > kMaxLength) {

return Local<Object>();

}

void* data;

if (length > 0) {

data = BufferMalloc(length);

if (data == nullptr)

return Local<Object>();

} else {

data = nullptr;

}

Local<ArrayBuffer> ab =

ArrayBuffer::New(env->isolate(),

data,

length,

ArrayBufferCreationMode::kInternalized);

Local<Uint8Array> ui = Uint8Array::New(ab, 0, length);

Maybe<bool> mb =

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

if (mb.FromMaybe(false))

return scope.Escape(ui);

// Object failed to be created. Clean up resources.

free(data);

return Local<Object>();

}

MaybeLocal<Object> Copy(Isolate* isolate, const char* data, size_t length) {

EscapableHandleScope handle_scope(isolate);

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

Local<Object> obj;

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

return handle_scope.Escape(obj);

return Local<Object>();

}

MaybeLocal<Object> Copy(Environment* env, const char* data, size_t length) {

EscapableHandleScope scope(env->isolate());

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

if (length > kMaxLength) {

return Local<Object>();

}

void* new_data;

if (length > 0) {

CHECK_NE(data, nullptr);

new_data = node::UncheckedMalloc(length);

if (new_data == nullptr)

return Local<Object>();

memcpy(new_data, data, length);

} else {

new_data = nullptr;

}

Local<ArrayBuffer> ab =

ArrayBuffer::New(env->isolate(),

new_data,

length,

ArrayBufferCreationMode::kInternalized);

Local<Uint8Array> ui = Uint8Array::New(ab, 0, length);

Maybe<bool> mb =

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

if (mb.FromMaybe(false))

return scope.Escape(ui);

// Object failed to be created. Clean up resources.

free(new_data);

return Local<Object>();

}

MaybeLocal<Object> New(Isolate* isolate,

char* data,

size_t length,

FreeCallback callback,

void* hint) {

EscapableHandleScope handle_scope(isolate);

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

Local<Object> obj;

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

return handle_scope.Escape(obj);

return Local<Object>();

}

MaybeLocal<Object> New(Environment* env,

char* data,

size_t length,

FreeCallback callback,

void* hint) {

EscapableHandleScope scope(env->isolate());

if (length > kMaxLength) {

return Local<Object>();

}

Local<ArrayBuffer> ab = ArrayBuffer::New(env->isolate(), data, length);

// `Neuter()`ing is required here to prevent materialization of the backing

// store in v8. `nullptr` buffers are not writable, so this is semantically

// correct.

if (data == nullptr)

ab->Neuter();

Local<Uint8Array> ui = Uint8Array::New(ab, 0, length);

Maybe<bool> mb =

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

if (!mb.FromMaybe(false))

return Local<Object>();

CallbackInfo::New(env->isolate(), ab, callback, data, hint);

return scope.Escape(ui);

}

MaybeLocal<Object> New(Isolate* isolate, char* data, size_t length) {

EscapableHandleScope handle_scope(isolate);

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

Local<Object> obj;

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

return handle_scope.Escape(obj);

return Local<Object>();

}

MaybeLocal<Object> New(Environment* env, char* data, size_t length) {

EscapableHandleScope scope(env->isolate());

if (length > 0) {

CHECK_NE(data, nullptr);

CHECK(length <= kMaxLength);

}

Local<ArrayBuffer> ab =

ArrayBuffer::New(env->isolate(),

data,

length,

ArrayBufferCreationMode::kInternalized);

Local<Uint8Array> ui = Uint8Array::New(ab, 0, length);

Maybe<bool> mb =

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

if (mb.FromMaybe(false))

return scope.Escape(ui);

return Local<Object>();

}

void CreateFromString(const FunctionCallbackInfo<Value>& args) {

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

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

enum encoding enc = ParseEncoding(args.GetIsolate(),

args[1].As<String>(),

UTF8);

Local<Object> buf;

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

args.GetReturnValue().Set(buf);

}

template <encoding encoding>

void StringSlice(const FunctionCallbackInfo<Value>& args) {

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

Isolate* isolate = env->isolate();

THROW_AND_RETURN_UNLESS_BUFFER(env, args.This());

SPREAD_BUFFER_ARG(args.This(), ts_obj);

if (ts_obj_length == 0)

return args.GetReturnValue().SetEmptyString();

SLICE_START_END(args[0], args[1], ts_obj_length)

args.GetReturnValue().Set(

StringBytes::Encode(isolate, ts_obj_data + start, length, encoding));

}

template <>

void StringSlice<UCS2>(const FunctionCallbackInfo<Value>& args) {

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

THROW_AND_RETURN_UNLESS_BUFFER(env, args.This());

SPREAD_BUFFER_ARG(args.This(), ts_obj);

if (ts_obj_length == 0)

return args.GetReturnValue().SetEmptyString();

SLICE_START_END(args[0], args[1], ts_obj_length)

length /= 2;

const char* data = ts_obj_data + start;

const uint16_t* buf;

bool release = false;

// Node's "ucs2" encoding expects LE character data inside a Buffer, so we

// need to reorder on BE platforms. See http://nodejs.org/api/buffer.html

// regarding Node's "ucs2" encoding specification.

const bool aligned = (reinterpret_cast<uintptr_t>(data) % sizeof(*buf) == 0);

if (IsLittleEndian() && !aligned) {

// Make a copy to avoid unaligned accesses in v8::String::NewFromTwoByte().

// This applies ONLY to little endian platforms, as misalignment will be

// handled by a byte-swapping operation in StringBytes::Encode on

// big endian platforms.

uint16_t* copy = new uint16_t[length];

for (size_t i = 0, k = 0; i < length; i += 1, k += 2) {

// Assumes that the input is little endian.

const uint8_t lo = static_cast<uint8_t>(data[k + 0]);

const uint8_t hi = static_cast<uint8_t>(data[k + 1]);

copy[i] = lo | hi << 8;

}

buf = copy;

release = true;

} else {

buf = reinterpret_cast<const uint16_t*>(data);

}

args.GetReturnValue().Set(StringBytes::Encode(env->isolate(), buf, length));

if (release)

delete[] buf;

}

void Latin1Slice(const FunctionCallbackInfo<Value>& args) {

StringSlice<LATIN1>(args);

}

void AsciiSlice(const FunctionCallbackInfo<Value>& args) {

StringSlice<ASCII>(args);

}

void Utf8Slice(const FunctionCallbackInfo<Value>& args) {

StringSlice<UTF8>(args);

}

void Ucs2Slice(const FunctionCallbackInfo<Value>& args) {

StringSlice<UCS2>(args);

}

void HexSlice(const FunctionCallbackInfo<Value>& args) {

StringSlice<HEX>(args);

}

void Base64Slice(const FunctionCallbackInfo<Value>& args) {

StringSlice<BASE64>(args);

}

// bytesCopied = copy(buffer, target[, targetStart][, sourceStart][, sourceEnd])

void Copy(const FunctionCallbackInfo<Value> &args) {

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

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[1]);

Local<Object> buffer_obj = args[0].As<Object>();

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

SPREAD_BUFFER_ARG(buffer_obj, ts_obj);

SPREAD_BUFFER_ARG(target_obj, target);

size_t target_start;

size_t source_start;

size_t source_end;

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

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

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(args[4], ts_obj_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 > ts_obj_length)

return env->ThrowRangeError("out of range index");

if (source_end - source_start > target_length - target_start)

source_end = source_start + target_length - target_start;

uint32_t to_copy = MIN(MIN(source_end - source_start,

target_length - target_start),

ts_obj_length - source_start);

memmove(target_data + target_start, ts_obj_data + source_start, to_copy);

args.GetReturnValue().Set(to_copy);

}

void Fill(const FunctionCallbackInfo<Value>& args) {

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

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

SPREAD_BUFFER_ARG(args[0], ts_obj);

size_t start = args[2]->Uint32Value();

size_t end = args[3]->Uint32Value();

size_t fill_length = end - start;

Local<String> str_obj;

size_t str_length;

enum encoding enc;

THROW_AND_RETURN_IF_OOB(start <= end);

THROW_AND_RETURN_IF_OOB(fill_length + start <= ts_obj_length);

// 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, MIN(str_length, fill_length));

goto start_fill;

}

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

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

int value = args[1]->Uint32Value() & 255;

memset(ts_obj_data + start, value, fill_length);

return;

}

str_obj = args[1]->ToString(env->isolate());

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

str_length =

enc == UTF8 ? str_obj->Utf8Length() :

enc == UCS2 ? str_obj->Length() * sizeof(uint16_t) : str_obj->Length();

if (enc == HEX && str_length % 2 != 0)

return env->ThrowTypeError("Invalid hex string");

if (str_length == 0)

return;

// 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) {

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

memcpy(ts_obj_data + start, *str, MIN(str_length, fill_length));

} else if (enc == UCS2) {

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

if (IsBigEndian())

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

memcpy(ts_obj_data + start, *str, 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,

nullptr);

// This check is also needed in case Write() returns that no bytes could

// be written.

// TODO(trevnorris): Should this throw? Because of the string length was

// greater than 0 but couldn't be written then the string was invalid.

if (str_length == 0)

return;

}

start_fill:

if (str_length >= fill_length)

return;

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);

}

}

template <encoding encoding>

void StringWrite(const FunctionCallbackInfo<Value>& args) {

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

THROW_AND_RETURN_UNLESS_BUFFER(env, args.This());

SPREAD_BUFFER_ARG(args.This(), ts_obj);

if (!args[0]->IsString())

return env->ThrowTypeError("Argument must be a string");

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

if (encoding == HEX && str->Length() % 2 != 0)

return env->ThrowTypeError("Invalid hex string");

size_t offset;

size_t max_length;

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

if (offset > ts_obj_length)

return env->ThrowRangeError("Offset is out of bounds");

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

&max_length));

max_length = 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,

nullptr);

args.GetReturnValue().Set(written);

}

void Base64Write(const FunctionCallbackInfo<Value>& args) {

StringWrite<BASE64>(args);

}

void Latin1Write(const FunctionCallbackInfo<Value>& args) {

StringWrite<LATIN1>(args);

}

void Utf8Write(const FunctionCallbackInfo<Value>& args) {

StringWrite<UTF8>(args);

}

void Ucs2Write(const FunctionCallbackInfo<Value>& args) {

StringWrite<UCS2>(args);

}

void HexWrite(const FunctionCallbackInfo<Value>& args) {

StringWrite<HEX>(args);

}

void AsciiWrite(const FunctionCallbackInfo<Value>& args) {

StringWrite<ASCII>(args);

}

static inline void Swizzle(char* start, unsigned int len) {

char* end = start + len - 1;

while (start < end) {

char tmp = *start;

*start++ = *end;

*end-- = tmp;

}

}

template <typename T, enum Endianness endianness>

void ReadFloatGeneric(const FunctionCallbackInfo<Value>& args) {

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

SPREAD_BUFFER_ARG(args[0], ts_obj);

uint32_t offset = args[1]->Uint32Value();

CHECK_LE(offset + sizeof(T), ts_obj_length);

union NoAlias {

T val;

char bytes[sizeof(T)];

};

union NoAlias na;

const char* ptr = static_cast<const char*>(ts_obj_data) + offset;

memcpy(na.bytes, ptr, sizeof(na.bytes));

if (endianness != GetEndianness())

Swizzle(na.bytes, sizeof(na.bytes));

args.GetReturnValue().Set(na.val);

}

void ReadFloatLE(const FunctionCallbackInfo<Value>& args) {

ReadFloatGeneric<float, kLittleEndian>(args);

}

void ReadFloatBE(const FunctionCallbackInfo<Value>& args) {

ReadFloatGeneric<float, kBigEndian>(args);

}

void ReadDoubleLE(const FunctionCallbackInfo<Value>& args) {

ReadFloatGeneric<double, kLittleEndian>(args);

}

void ReadDoubleBE(const FunctionCallbackInfo<Value>& args) {

ReadFloatGeneric<double, kBigEndian>(args);

}

template <typename T, enum Endianness endianness>

void WriteFloatGeneric(const FunctionCallbackInfo<Value>& args) {

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

bool should_assert = args.Length() < 4;

if (should_assert) {

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

}

Local<Uint8Array> ts_obj = args[0].As<Uint8Array>();

ArrayBuffer::Contents ts_obj_c = ts_obj->Buffer()->GetContents();

const size_t ts_obj_offset = ts_obj->ByteOffset();

const size_t ts_obj_length = ts_obj->ByteLength();

char* const ts_obj_data =

static_cast<char*>(ts_obj_c.Data()) + ts_obj_offset;

if (ts_obj_length > 0)

CHECK_NE(ts_obj_data, nullptr);

T val = args[1]->NumberValue(env->context()).FromMaybe(0);

size_t offset = args[2]->IntegerValue(env->context()).FromMaybe(0);

size_t memcpy_num = sizeof(T);

if (should_assert) {

THROW_AND_RETURN_IF_OOB(offset + memcpy_num >= memcpy_num);

THROW_AND_RETURN_IF_OOB(offset + memcpy_num <= ts_obj_length);

}

if (offset + memcpy_num > ts_obj_length)

memcpy_num = ts_obj_length - offset;

union NoAlias {

T val;

char bytes[sizeof(T)];

};

union NoAlias na = { val };

char* ptr = static_cast<char*>(ts_obj_data) + offset;

if (endianness != GetEndianness())

Swizzle(na.bytes, sizeof(na.bytes));

memcpy(ptr, na.bytes, memcpy_num);

}

void WriteFloatLE(const FunctionCallbackInfo<Value>& args) {

WriteFloatGeneric<float, kLittleEndian>(args);

}

void WriteFloatBE(const FunctionCallbackInfo<Value>& args) {

WriteFloatGeneric<float, kBigEndian>(args);

}

void WriteDoubleLE(const FunctionCallbackInfo<Value>& args) {

WriteFloatGeneric<double, kLittleEndian>(args);

}

void WriteDoubleBE(const FunctionCallbackInfo<Value>& args) {

WriteFloatGeneric<double, kBigEndian>(args);

}

void ByteLengthUtf8(const FunctionCallbackInfo<Value> &args) {

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

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

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

}

// Normalize val to be an integer in the range of [1, -1] since

// implementations of memcmp() can vary by platform.

static int normalizeCompareVal(int val, size_t a_length, size_t b_length) {

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;

}

void CompareOffset(const FunctionCallbackInfo<Value> &args) {

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

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[1]);

SPREAD_BUFFER_ARG(args[0], ts_obj);

SPREAD_BUFFER_ARG(args[1], target);

size_t target_start;

size_t source_start;

size_t source_end;

size_t target_end;

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

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

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(args[4], target_length, &target_end));

THROW_AND_RETURN_IF_OOB(ParseArrayIndex(args[5], ts_obj_length, &source_end));

if (source_start > ts_obj_length)

return env->ThrowRangeError("out of range index");

if (target_start > target_length)

return env->ThrowRangeError("out of range index");

CHECK_LE(source_start, source_end);

CHECK_LE(target_start, target_end);

size_t to_cmp = MIN(MIN(source_end - source_start,

target_end - target_start),

ts_obj_length - source_start);

int val = normalizeCompareVal(to_cmp > 0 ?

memcmp(ts_obj_data + source_start,

target_data + target_start,

to_cmp) : 0,

source_end - source_start,

target_end - target_start);

args.GetReturnValue().Set(val);

}

void Compare(const FunctionCallbackInfo<Value> &args) {

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

THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);

THROW_AND_RETURN_UNLESS_BUFFER(env, args[1]);

SPREAD_BUFFER_ARG(args[0], obj_a);

SPREAD_BUFFER_ARG(args[1], obj_b);

size_t cmp_length = MIN(obj_a_length, obj_b_length);

int val = normalizeCompareVal(cmp_length > 0 ?

memcmp(obj_a_data, obj_b_data, cmp_length) : 0,

obj_a_length, obj_b_length);

args.GetReturnValue().Set(val);

}

// Computes the offset for starting an indexOf or lastIndexOf search.

// Returns either a valid offset in [0...<length - 1>], ie inside the Buffer,

// or -1 to signal that there is no possible match.

int64_t IndexOfOffset(size_t length, int64_t offset_i64, bool is_forward) {

int64_t length_i64 = static_cast<int64_t>(length);

if (length_i64 == 0) {

// Empty buffer, no match.

return -1;

}

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) {

// 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 < length_i64) {

// Valid positive offset.

return offset_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;

}

}

}

void IndexOfString(const FunctionCallbackInfo<Value>& args) {

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

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

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

enum encoding enc = ParseEncoding(args.GetIsolate(),

args[3],

UTF8);

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

SPREAD_BUFFER_ARG(args[0], ts_obj);

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

int64_t offset_i64 = args[2]->IntegerValue();

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

const char* haystack = ts_obj_data;

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

const size_t haystack_length = (enc == UCS2) ?

ts_obj_length &~ 1 : ts_obj_length; // NOLINT(whitespace/operators)

const size_t needle_length =

StringBytes::Size(args.GetIsolate(), needle, enc);

if (needle_length == 0 || haystack_length == 0) {

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

}

int64_t opt_offset = IndexOfOffset(haystack_length, offset_i64, is_forward);

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(needle);

if (*needle_value == nullptr)