public:

~ExternString() override {

free(const_cast<TypeName*>(data_));

isolate()->AdjustAmountOfExternalAllocatedMemory(-byte_length());

}

const TypeName* data() const override {

return data_;

}

size_t length() const override {

return length_;

}

int64_t byte_length() const {

return length() * sizeof(*data());

}

static Local<String> NewFromCopy(Isolate* isolate,

const TypeName* data,

size_t length) {

EscapableHandleScope scope(isolate);

if (length == 0)

return scope.Escape(String::Empty(isolate));

TypeName* new_data =

static_cast<TypeName*>(malloc(length * sizeof(*new_data)));

if (new_data == nullptr) {

return Local<String>();

}

memcpy(new_data, data, length * sizeof(*new_data));

return scope.Escape(ExternString<ResourceType, TypeName>::New(isolate,

new_data,

length));

}

// uses "data" for external resource, and will be free'd on gc

static Local<String> New(Isolate* isolate,

const TypeName* data,

size_t length) {

EscapableHandleScope scope(isolate);

if (length == 0)

return scope.Escape(String::Empty(isolate));

ExternString* h_str = new ExternString<ResourceType, TypeName>(isolate,

data,

length);

MaybeLocal<String> str = NewExternal(isolate, h_str);

isolate->AdjustAmountOfExternalAllocatedMemory(h_str->byte_length());

if (str.IsEmpty()) {

delete h_str;

return Local<String>();

}

return scope.Escape(str.ToLocalChecked());

}

inline Isolate* isolate() const { return isolate_; }

private:

ExternString(Isolate* isolate, const TypeName* data, size_t length)

: isolate_(isolate), data_(data), length_(length) { }

static MaybeLocal<String> NewExternal(Isolate* isolate,

ExternString* h_str);

Isolate* isolate_;

const TypeName* data_;

size_t length_;

size_t remainder = size % 4;

size = (size / 4) * 3;

if (remainder) {

if (size == 0 && remainder == 1) {

// special case: 1-byte input cannot be decoded

size = 0;

} else {

// non-padded input, add 1 or 2 extra bytes

size += 1 + (remainder == 3);

}

}

return size;

if (size == 0)

return 0;

if (src[size - 1] == '=')

size--;

if (size > 0 && src[size - 1] == '=')

size--;

return base64_decoded_size_fast(size);

const TypeName* src, size_t srclen) {

uint8_t hi;

uint8_t lo;

size_t i = 0;

size_t k = 0;

for (;;) {

#define V(expr) \

while (i < srclen) { \

const uint8_t c = src[i]; \

lo = unbase64(c); \

i += 1; \

if (lo < 64) \

break; /* Legal character. */ \

if (c == '=') \

return k; \

} \

expr; \

if (i >= srclen) \

return k; \

if (k >= dstlen) \

return k; \

hi = lo;

V(/* Nothing. */);

V(dst[k++] = ((hi & 0x3F) << 2) | ((lo & 0x30) >> 4));

V(dst[k++] = ((hi & 0x0F) << 4) | ((lo & 0x3C) >> 2));

V(dst[k++] = ((hi & 0x03) << 6) | ((lo & 0x3F) >> 0));

#undef V

const TypeName* const src, const size_t srclen,

const size_t decoded_size) {

const size_t available = dstlen < decoded_size ? dstlen : decoded_size;

const size_t max_i = srclen / 4 * 4;

const size_t max_k = available / 3 * 3;

size_t i = 0;

size_t k = 0;

while (i < max_i && k < max_k) {

const uint32_t v =

unbase64(src[i + 0]) << 24 |

unbase64(src[i + 1]) << 16 |

unbase64(src[i + 2]) << 8 |

unbase64(src[i + 3]);

// If MSB is set, input contains whitespace or is not valid base64.

if (v & 0x80808080) {

break;

}

dst[k + 0] = ((v >> 22) & 0xFC) | ((v >> 20) & 0x03);

dst[k + 1] = ((v >> 12) & 0xF0) | ((v >> 10) & 0x0F);

dst[k + 2] = ((v >> 2) & 0xC0) | ((v >> 0) & 0x3F);

i += 4;

k += 3;

}

if (i < srclen && k < dstlen) {

return k + base64_decode_slow(dst + k, dstlen - k, src + i, srclen - i);

}

return k;

const TypeName* const src, const size_t srclen) {

const size_t decoded_size = base64_decoded_size(src, srclen);

return base64_decode_fast(dst, dstlen, src, srclen, decoded_size);

if (c >= '0' && c <= '9')

return c - '0';

if (c >= 'A' && c <= 'F')

return 10 + (c - 'A');

if (c >= 'a' && c <= 'f')

return 10 + (c - 'a');

return static_cast<unsigned>(-1);

size_t len,

const TypeName* src,

const size_t srcLen) {

size_t i;

for (i = 0; i < len && i * 2 + 1 < srcLen; ++i) {

unsigned a = hex2bin(src[i * 2 + 0]);

unsigned b = hex2bin(src[i * 2 + 1]);

if (!~a || !~b)

return i;

buf[i] = a * 16 + b;

}

return i;

Local<Value> val,

const char** data,

size_t* len) {

if (Buffer::HasInstance(val)) {

*data = Buffer::Data(val);

*len = Buffer::Length(val);

return true;

}

if (!val->IsString())

return false;

Local<String> str = val.As<String>();

if (str->IsExternalOneByte()) {

const String::ExternalOneByteStringResource* ext;

ext = str->GetExternalOneByteStringResource();

*data = ext->data();

*len = ext->length();

return true;

} else if (str->IsExternal()) {

const String::ExternalStringResource* ext;

ext = str->GetExternalStringResource();

*data = reinterpret_cast<const char*>(ext->data());

*len = ext->length() * sizeof(*ext->data());

return true;

}

return false;

size_t buflen,

size_t nbytes,

const char* data,

Local<String> str,

int flags,

size_t* chars_written) {

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

size_t max_chars = (buflen / sizeof(*dst));

size_t nchars;

size_t alignment = reinterpret_cast<uintptr_t>(dst) % sizeof(*dst);

if (alignment == 0) {

nchars = str->Write(dst, 0, max_chars, flags);

*chars_written = nchars;

return nchars * sizeof(*dst);

}

uint16_t* aligned_dst =

reinterpret_cast<uint16_t*>(buf + sizeof(*dst) - alignment);

ASSERT_EQ(reinterpret_cast<uintptr_t>(aligned_dst) % sizeof(*dst), 0);

// Write all but the last char

nchars = str->Write(aligned_dst, 0, max_chars - 1, flags);

// Shift everything to unaligned-left

memmove(dst, aligned_dst, nchars * sizeof(*dst));

// One more char to be written

uint16_t last;

if (nchars == max_chars - 1 && str->Write(&last, nchars, 1, flags) != 0) {

memcpy(buf + nchars * sizeof(*dst), &last, sizeof(last));

nchars++;

}

*chars_written = nchars;

return nchars * sizeof(*dst);

char* buf,

size_t buflen,

Local<Value> val,

enum encoding encoding,

int* chars_written) {

HandleScope scope(isolate);

const char* data = nullptr;

size_t nbytes = 0;

const bool is_extern = GetExternalParts(isolate, val, &data, &nbytes);

const size_t external_nbytes = nbytes;

CHECK(val->IsString() == true);

Local<String> str = val.As<String>();

if (nbytes > buflen)

nbytes = buflen;

int flags = String::HINT_MANY_WRITES_EXPECTED |

String::NO_NULL_TERMINATION |

String::REPLACE_INVALID_UTF8;

switch (encoding) {

case ASCII:

case BINARY:

if (is_extern && str->IsOneByte()) {

memcpy(buf, data, nbytes);

} else {

uint8_t* const dst = reinterpret_cast<uint8_t*>(buf);

nbytes = str->WriteOneByte(dst, 0, buflen, flags);

}

if (chars_written != nullptr)

*chars_written = nbytes;

break;

case BUFFER:

case UTF8:

nbytes = str->WriteUtf8(buf, buflen, chars_written, flags);

break;

case UCS2: {

size_t nchars;

if (is_extern && !str->IsOneByte()) {

memcpy(buf, data, nbytes);

nchars = nbytes / sizeof(uint16_t);

} else {

nbytes = WriteUCS2(buf, buflen, nbytes, data, str, flags, &nchars);

}

if (chars_written != nullptr)

*chars_written = nchars;

if (!IsBigEndian())

break;

// Node's "ucs2" encoding wants LE character data stored in

// the Buffer, so we need to reorder on BE platforms. See

// http://nodejs.org/api/buffer.html regarding Node's "ucs2"

// encoding specification

const bool is_aligned =

reinterpret_cast<uintptr_t>(buf) % sizeof(uint16_t);

if (is_aligned) {

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

SwapBytes(dst, dst, nchars);

}

ASSERT_EQ(sizeof(uint16_t), 2);

for (size_t i = 0; i < nchars; i++) {

char tmp = buf[i * 2];

buf[i * 2] = buf[i * 2 + 1];

buf[i * 2 + 1] = tmp;

}

break;

}

case BASE64:

if (is_extern) {

nbytes = base64_decode(buf, buflen, data, external_nbytes);

} else {

String::Value value(str);

nbytes = base64_decode(buf, buflen, *value, value.length());

}

if (chars_written != nullptr) {

*chars_written = nbytes;

}

break;

case HEX:

if (is_extern) {

nbytes = hex_decode(buf, buflen, data, external_nbytes);

} else {

String::Value value(str);

nbytes = hex_decode(buf, buflen, *value, value.length());

}

if (chars_written != nullptr) {

*chars_written = nbytes;

}

break;

default:

CHECK(0 && "unknown encoding");

break;

}

return nbytes;

Local<String> string,

enum encoding enc) {

if (enc == HEX && string->Length() % 2 != 0)

return false;

// TODO(bnoordhuis) Add BASE64 check?

return true;

Local<Value> val,

enum encoding encoding) {

HandleScope scope(isolate);

size_t data_size = 0;

bool is_buffer = Buffer::HasInstance(val);

if (is_buffer && (encoding == BUFFER || encoding == BINARY)) {

return Buffer::Length(val);

}

Local<String> str = val->ToString(isolate);

switch (encoding) {

case BINARY:

case ASCII:

data_size = str->Length();

break;

case BUFFER:

case UTF8:

// A single UCS2 codepoint never takes up more than 3 utf8 bytes.

// It is an exercise for the caller to decide when a string is

// long enough to justify calling Size() instead of StorageSize()

data_size = 3 * str->Length();

break;

case UCS2:

data_size = str->Length() * sizeof(uint16_t);

break;

case BASE64:

data_size = base64_decoded_size_fast(str->Length());

break;

case HEX:

CHECK(str->Length() % 2 == 0 && "invalid hex string length");

data_size = str->Length() / 2;

break;

default:

CHECK(0 && "unknown encoding");

break;

}

return data_size;

Local<Value> val,

enum encoding encoding) {

HandleScope scope(isolate);

size_t data_size = 0;

bool is_buffer = Buffer::HasInstance(val);

if (is_buffer && (encoding == BUFFER || encoding == BINARY))

return Buffer::Length(val);

const char* data;

if (GetExternalParts(isolate, val, &data, &data_size))

return data_size;

Local<String> str = val->ToString(isolate);

switch (encoding) {

case BINARY:

case ASCII:

data_size = str->Length();

break;

case BUFFER:

case UTF8:

data_size = str->Utf8Length();

break;

case UCS2:

data_size = str->Length() * sizeof(uint16_t);

break;

case BASE64: {

String::Value value(str);

data_size = base64_decoded_size(*value, value.length());

break;

}

case HEX:

data_size = str->Length() / 2;

break;

default:

CHECK(0 && "unknown encoding");

break;

}

return data_size;

for (size_t i = 0; i < len; ++i) {

if (buf[i] & 0x80)

return true;

}

return false;

if (len < 16) {

return contains_non_ascii_slow(src, len);

}

const unsigned bytes_per_word = sizeof(uintptr_t);

const unsigned align_mask = bytes_per_word - 1;

const unsigned unaligned = reinterpret_cast<uintptr_t>(src) & align_mask;

if (unaligned > 0) {

const unsigned n = bytes_per_word - unaligned;

if (contains_non_ascii_slow(src, n))

return true;

src += n;

len -= n;

}

#if defined(_WIN64) || defined(_LP64)

const uintptr_t mask = 0x8080808080808080ll;

#else

const uintptr_t mask = 0x80808080l;

#endif

const uintptr_t* srcw = reinterpret_cast<const uintptr_t*>(src);

for (size_t i = 0, n = len / bytes_per_word; i < n; ++i) {

if (srcw[i] & mask)

return true;

}

const unsigned remainder = len & align_mask;

if (remainder > 0) {

const size_t offset = len - remainder;

if (contains_non_ascii_slow(src + offset, remainder))

return true;

}

return false;

for (size_t i = 0; i < len; ++i) {

dst[i] = src[i] & 0x7f;

}

if (len < 16) {

force_ascii_slow(src, dst, len);

return;

}

const unsigned bytes_per_word = sizeof(uintptr_t);

const unsigned align_mask = bytes_per_word - 1;

const unsigned src_unalign = reinterpret_cast<uintptr_t>(src) & align_mask;

const unsigned dst_unalign = reinterpret_cast<uintptr_t>(dst) & align_mask;

if (src_unalign > 0) {

if (src_unalign == dst_unalign) {

const unsigned unalign = bytes_per_word - src_unalign;

force_ascii_slow(src, dst, unalign);

src += unalign;

dst += unalign;

len -= src_unalign;

} else {

force_ascii_slow(src, dst, len);

return;

}

}

#if defined(_WIN64) || defined(_LP64)

const uintptr_t mask = ~0x8080808080808080ll;

#else

const uintptr_t mask = ~0x80808080l;

#endif

const uintptr_t* srcw = reinterpret_cast<const uintptr_t*>(src);

uintptr_t* dstw = reinterpret_cast<uintptr_t*>(dst);

for (size_t i = 0, n = len / bytes_per_word; i < n; ++i) {

dstw[i] = srcw[i] & mask;

}

const unsigned remainder = len & align_mask;

if (remainder > 0) {

const size_t offset = len - remainder;

force_ascii_slow(src + offset, dst + offset, remainder);

}

size_t slen,

char* dst,

size_t dlen) {

// We know how much we'll write, just make sure that there's space.

CHECK(dlen >= base64_encoded_size(slen) &&

"not enough space provided for base64 encode");

dlen = base64_encoded_size(slen);

unsigned a;

unsigned b;

unsigned c;

unsigned i;

unsigned k;

unsigned n;

static const char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

"abcdefghijklmnopqrstuvwxyz"

"0123456789+/";

i = 0;

k = 0;

n = slen / 3 * 3;

while (i < n) {

a = src[i + 0] & 0xff;

b = src[i + 1] & 0xff;

c = src[i + 2] & 0xff;

dst[k + 0] = table[a >> 2];

dst[k + 1] = table[((a & 3) << 4) | (b >> 4)];

dst[k + 2] = table[((b & 0x0f) << 2) | (c >> 6)];

dst[k + 3] = table[c & 0x3f];

i += 3;

k += 4;

}

if (n != slen) {

switch (slen - n) {

case 1:

a = src[i + 0] & 0xff;

dst[k + 0] = table[a >> 2];

dst[k + 1] = table[(a & 3) << 4];

dst[k + 2] = '=';

dst[k + 3] = '=';

break;

case 2:

a = src[i + 0] & 0xff;

b = src[i + 1] & 0xff;

dst[k + 0] = table[a >> 2];

dst[k + 1] = table[((a & 3) << 4) | (b >> 4)];

dst[k + 2] = table[(b & 0x0f) << 2];

dst[k + 3] = '=';

break;

}

}

return dlen;

// We know how much we'll write, just make sure that there's space.

CHECK(dlen >= slen * 2 &&

"not enough space provided for hex encode");

dlen = slen * 2;

for (uint32_t i = 0, k = 0; k < dlen; i += 1, k += 2) {

static const char hex[] = "0123456789abcdef";

uint8_t val = static_cast<uint8_t>(src[i]);

dst[k + 0] = hex[val >> 4];

dst[k + 1] = hex[val & 15];

}

return dlen;

const char* buf,

size_t buflen,

enum encoding encoding) {

EscapableHandleScope scope(isolate);

CHECK_NE(encoding, UCS2);

CHECK_LE(buflen, Buffer::kMaxLength);

if (!buflen && encoding != BUFFER)

return scope.Escape(String::Empty(isolate));

Local<String> val;

switch (encoding) {

case BUFFER:

{

Local<Object> vbuf =

Buffer::Copy(isolate, buf, buflen).ToLocalChecked();

return scope.Escape(vbuf);

}

case ASCII:

if (contains_non_ascii(buf, buflen)) {

char* out = static_cast<char*>(malloc(buflen));

if (out == nullptr) {

return Local<String>();

}

force_ascii(buf, out, buflen);

if (buflen < EXTERN_APEX) {

val = OneByteString(isolate, out, buflen);

free(out);

} else {

val = ExternOneByteString::New(isolate, out, buflen);

}

} else {

if (buflen < EXTERN_APEX)

val = OneByteString(isolate, buf, buflen);

else

val = ExternOneByteString::NewFromCopy(isolate, buf, buflen);

}

break;

case UTF8:

val = String::NewFromUtf8(isolate,

buf,

String::kNormalString,

buflen);

break;

case BINARY:

if (buflen < EXTERN_APEX)

val = OneByteString(isolate, buf, buflen);

else

val = ExternOneByteString::NewFromCopy(isolate, buf, buflen);

break;

case BASE64: {

size_t dlen = base64_encoded_size(buflen);

char* dst = static_cast<char*>(malloc(dlen));

if (dst == nullptr) {

return Local<String>();

}

size_t written = base64_encode(buf, buflen, dst, dlen);

CHECK_EQ(written, dlen);

if (dlen < EXTERN_APEX) {

val = OneByteString(isolate, dst, dlen);

free(dst);

} else {

val = ExternOneByteString::New(isolate, dst, dlen);

}

break;

}

case HEX: {

size_t dlen = buflen * 2;

char* dst = static_cast<char*>(malloc(dlen));

if (dst == nullptr) {

return Local<String>();

}

size_t written = hex_encode(buf, buflen, dst, dlen);

CHECK_EQ(written, dlen);

if (dlen < EXTERN_APEX) {

val = OneByteString(isolate, dst, dlen);

free(dst);

} else {

val = ExternOneByteString::New(isolate, dst, dlen);

}

break;

}

default:

CHECK(0 && "unknown encoding");

break;

}

return scope.Escape(val);

const uint16_t* buf,

size_t buflen) {

Local<String> val;

std::vector<uint16_t> dst;

if (IsBigEndian()) {

// 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

dst.resize(buflen);

SwapBytes(&dst[0], buf, buflen);

buf = &dst[0];

}

if (buflen < EXTERN_APEX) {

val = String::NewFromTwoByte(isolate,

buf,

String::kNormalString,

buflen);

} else {

val = ExternTwoByteString::NewFromCopy(isolate, buf, buflen);

}

return val;

const char* buf,

enum encoding encoding) {

const size_t len = strlen(buf);

Local<Value> ret;

if (encoding == UCS2) {

// In Node, UCS2 means utf16le. The data must be in little-endian

// order and must be aligned on 2-bytes. This returns an empty

// value if it's not aligned and ensures the appropriate byte order

// on big endian architectures.

const bool be = IsBigEndian();

if (len % 2 != 0)

return ret;

std::vector<uint16_t> vec(len / 2);

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

const uint8_t hi = static_cast<uint8_t>(buf[i + 0]);

const uint8_t lo = static_cast<uint8_t>(buf[i + 1]);

vec[k] = be ?

static_cast<uint16_t>(hi) << 8 | lo

: static_cast<uint16_t>(lo) << 8 | hi;

}

ret = vec.empty() ?

static_cast< Local<Value> >(String::Empty(isolate))

: StringBytes::Encode(isolate, &vec[0], vec.size());

} else {

ret = StringBytes::Encode(isolate, buf, len, encoding);

}

return ret;