node/src/node_buffer.cc at b5359e40be91c113feef45ff4e1be65cffe337d0 · cnusbaum/node · GitHub

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#include <node_buffer.h>

#include <assert.h>

#include <stdlib.h> // malloc, free

#include <v8.h>

#include <string.h> // memcpy

#include <arpa/inet.h> // htons, htonl

#include <node.h>

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

namespace node {

using namespace v8;

#define SLICE_ARGS(start_arg, end_arg) \

if (!start_arg->IsInt32() || !end_arg->IsInt32()) { \

return ThrowException(Exception::TypeError( \

String::New("Bad argument."))); \

} \

int32_t start = start_arg->Int32Value(); \

int32_t end = end_arg->Int32Value(); \

if (start < 0 || end < 0) { \

return ThrowException(Exception::TypeError( \

String::New("Bad argument."))); \

} \

if (!(start <= end)) { \

return ThrowException(Exception::Error( \

String::New("Must have start <= end"))); \

} \

if ((size_t)end > parent->length_) { \

return ThrowException(Exception::Error( \

String::New("end cannot be longer than parent.length"))); \

}

static Persistent<String> length_symbol;

static Persistent<String> chars_written_sym;

static Persistent<String> write_sym;

Persistent<FunctionTemplate> Buffer::constructor_template;

static inline size_t base64_decoded_size(const char *src, size_t size) {

const char *const end = src + size;

const int 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);

}

// check for trailing padding (1 or 2 bytes)

if (size > 0) {

if (end[-1] == '=') size--;

if (end[-2] == '=') size--;

}

return size;

}

static size_t ByteLength (Handle<String> string, enum encoding enc) {

HandleScope scope;

if (enc == UTF8) {

return string->Utf8Length();

} else if (enc == BASE64) {

String::Utf8Value v(string);

return base64_decoded_size(*v, v.length());

} else {

return string->Length();

}

Buffer* Buffer::New(size_t size) {

HandleScope scope;

Local<Value> arg = Integer::NewFromUnsigned(size);

Local<Object> b = constructor_template->GetFunction()->NewInstance(1, &arg);

return ObjectWrap::Unwrap<Buffer>(b);

}

char* Buffer::Data(Handle<Object> obj) {

if (obj->HasIndexedPropertiesInPixelData()) {

return (char*)obj->GetIndexedPropertiesPixelData();

}

HandleScope scope;

// Return true for "SlowBuffer"

if (constructor_template->HasInstance(obj)) {

return ObjectWrap::Unwrap<Buffer>(obj)->data_;

}

// Not a buffer.

return NULL;

}

size_t Buffer::Length(Handle<Object> obj) {

if (obj->HasIndexedPropertiesInPixelData()) {

return (size_t)obj->GetIndexedPropertiesPixelDataLength();

}

HandleScope scope;

// Return true for "SlowBuffer"

if (constructor_template->HasInstance(obj)) {

return ObjectWrap::Unwrap<Buffer>(obj)->length_;

}

// Not a buffer.

return 0;

}

Handle<Value> Buffer::New(const Arguments &args) {

if (!args.IsConstructCall()) {

return FromConstructorTemplate(constructor_template, args);

}

HandleScope scope;

Buffer *buffer;

if (args[0]->IsInt32()) {

// var buffer = new Buffer(1024);

size_t length = args[0]->Uint32Value();

buffer = new Buffer(length);

} else {

return ThrowException(Exception::TypeError(String::New("Bad argument")));

}

buffer->Wrap(args.This());

args.This()->SetIndexedPropertiesToExternalArrayData(buffer->data_,

kExternalUnsignedByteArray,

buffer->length_);

args.This()->Set(length_symbol, Integer::New(buffer->length_));

return args.This();

}

Buffer::Buffer(size_t length) : ObjectWrap() {

off_ = 0;

length_ = length;

data_ = new char[length_];

V8::AdjustAmountOfExternalAllocatedMemory(sizeof(Buffer) + length_);

}

Buffer::~Buffer() {

//fprintf(stderr, "free buffer (%d refs left)\n", blob_->refs);

delete data_;

V8::AdjustAmountOfExternalAllocatedMemory(-(sizeof(Buffer) + length_));

}

Handle<Value> Buffer::BinarySlice(const Arguments &args) {

HandleScope scope;

Buffer *parent = ObjectWrap::Unwrap<Buffer>(args.This());

SLICE_ARGS(args[0], args[1])

char *data = parent->data_ + start;

//Local<String> string = String::New(data, end - start);

Local<Value> b = Encode(data, end - start, BINARY);

return scope.Close(b);

}

Handle<Value> Buffer::AsciiSlice(const Arguments &args) {

HandleScope scope;

Buffer *parent = ObjectWrap::Unwrap<Buffer>(args.This());

SLICE_ARGS(args[0], args[1])

char* data = parent->data_ + start;

Local<String> string = String::New(data, end - start);

return scope.Close(string);

}

Handle<Value> Buffer::Utf8Slice(const Arguments &args) {

HandleScope scope;

Buffer *parent = ObjectWrap::Unwrap<Buffer>(args.This());

SLICE_ARGS(args[0], args[1])

char *data = parent->data_ + start;

Local<String> string = String::New(data, end - start);

return scope.Close(string);

}

static const char *base64_table = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

"abcdefghijklmnopqrstuvwxyz"

"0123456789+/";

static const int unbase64_table[] =

{-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1

,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1

,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63

,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1

,-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14

,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1

,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40

,41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1

};

Handle<Value> Buffer::Base64Slice(const Arguments &args) {

HandleScope scope;

Buffer *parent = ObjectWrap::Unwrap<Buffer>(args.This());

SLICE_ARGS(args[0], args[1])

int n = end - start;

int out_len = (n + 2 - ((n + 2) % 3)) / 3 * 4;

char *out = new char[out_len];

uint8_t bitbuf[3];

int i = start; // data() index

int j = 0; // out index

char c;

bool b1_oob, b2_oob;

while (i < end) {

bitbuf[0] = parent->data_[i++];

if (i < end) {

bitbuf[1] = parent->data_[i];

b1_oob = false;

} else {

bitbuf[1] = 0;

b1_oob = true;

}

i++;

if (i < end) {

bitbuf[2] = parent->data_[i];

b2_oob = false;

} else {

bitbuf[2] = 0;

b2_oob = true;

}

i++;

c = bitbuf[0] >> 2;

assert(c < 64);

out[j++] = base64_table[c];

assert(j < out_len);

c = ((bitbuf[0] & 0x03) << 4) | (bitbuf[1] >> 4);

assert(c < 64);

out[j++] = base64_table[c];

assert(j < out_len);

if (b1_oob) {

out[j++] = '=';

} else {

c = ((bitbuf[1] & 0x0F) << 2) | (bitbuf[2] >> 6);

assert(c < 64);

out[j++] = base64_table[c];

}

assert(j < out_len);

if (b2_oob) {

out[j++] = '=';

} else {

c = bitbuf[2] & 0x3F;

assert(c < 64);

out[j++] = base64_table[c];

}

assert(j <= out_len);

}

Local<String> string = String::New(out, out_len);

delete [] out;

return scope.Close(string);

}

// var bytesCopied = buffer.copy(target, targetStart, sourceStart, sourceEnd);

Handle<Value> Buffer::Copy(const Arguments &args) {

HandleScope scope;

Buffer *source = ObjectWrap::Unwrap<Buffer>(args.This());

if (!Buffer::HasInstance(args[0])) {

return ThrowException(Exception::TypeError(String::New(

"First arg should be a Buffer")));

}

Buffer *target = ObjectWrap::Unwrap<Buffer>(args[0]->ToObject());

ssize_t target_start = args[1]->Int32Value();

ssize_t source_start = args[2]->Int32Value();

ssize_t source_end = args[3]->IsInt32() ? args[3]->Int32Value()

: source->length_;

if (source_end < source_start) {

return ThrowException(Exception::Error(String::New(

"sourceEnd < sourceStart")));

}

// Copy 0 bytes; we're done

if (source_end == source_start) {

return scope.Close(Integer::New(0));

}

if (target_start < 0 || target_start >= target->length_) {

return ThrowException(Exception::Error(String::New(

"targetStart out of bounds")));

}

if (source_start < 0 || source_start >= source->length_) {

return ThrowException(Exception::Error(String::New(

"sourceStart out of bounds")));

}

if (source_end < 0 || source_end > source->length_) {

return ThrowException(Exception::Error(String::New(

"sourceEnd out of bounds")));

}

ssize_t to_copy = MIN(MIN(source_end - source_start,

target->length_ - target_start),

source->length_ - source_start);

// need to use slightly slower memmove is the ranges might overlap

memmove((void*)(target->data_ + target_start),

(const void*)(source->data_ + source_start),

to_copy);

return scope.Close(Integer::New(to_copy));

}

// var charsWritten = buffer.utf8Write(string, offset, [maxLength]);

Handle<Value> Buffer::Utf8Write(const Arguments &args) {

HandleScope scope;

Buffer *buffer = ObjectWrap::Unwrap<Buffer>(args.This());

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

return ThrowException(Exception::TypeError(String::New(

"Argument must be a string")));

}

Local<String> s = args[0]->ToString();

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

if (s->Utf8Length() > 0 && offset >= buffer->length_) {

return ThrowException(Exception::TypeError(String::New(

"Offset is out of bounds")));

}

size_t max_length = args[2]->IsUndefined() ? buffer->length_ - offset

: args[2]->Uint32Value();

max_length = MIN(buffer->length_ - offset, max_length);

char* p = buffer->data_ + offset;

int char_written;

int written = s->WriteUtf8(p,

max_length,

&char_written,

String::HINT_MANY_WRITES_EXPECTED);

constructor_template->GetFunction()->Set(chars_written_sym,

Integer::New(char_written));

if (written > 0 && p[written-1] == '\0') written--;

return scope.Close(Integer::New(written));

}

// var charsWritten = buffer.asciiWrite(string, offset);

Handle<Value> Buffer::AsciiWrite(const Arguments &args) {

HandleScope scope;

Buffer *buffer = ObjectWrap::Unwrap<Buffer>(args.This());

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

return ThrowException(Exception::TypeError(String::New(

"Argument must be a string")));

}

Local<String> s = args[0]->ToString();

size_t offset = args[1]->Int32Value();

if (s->Length() > 0 && offset >= buffer->length_) {

return ThrowException(Exception::TypeError(String::New(

"Offset is out of bounds")));

}

size_t max_length = args[2]->IsUndefined() ? buffer->length_ - offset

: args[2]->Uint32Value();

max_length = MIN(s->Length(), MIN(buffer->length_ - offset, max_length));

char *p = buffer->data_ + offset;

int written = s->WriteAscii(p,

max_length,

String::HINT_MANY_WRITES_EXPECTED);

return scope.Close(Integer::New(written));

}

// var bytesWritten = buffer.base64Write(string, offset, [maxLength]);

Handle<Value> Buffer::Base64Write(const Arguments &args) {

HandleScope scope;

assert(unbase64_table['/'] == 63);

assert(unbase64_table['+'] == 62);

assert(unbase64_table['T'] == 19);

assert(unbase64_table['Z'] == 25);

assert(unbase64_table['t'] == 45);

assert(unbase64_table['z'] == 51);

Buffer *buffer = ObjectWrap::Unwrap<Buffer>(args.This());

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

return ThrowException(Exception::TypeError(String::New(

"Argument must be a string")));

}

String::AsciiValue s(args[0]->ToString());

size_t offset = args[1]->Int32Value();

// handle zero-length buffers graciously

if (offset == 0 && buffer->length_ == 0) {

return scope.Close(Integer::New(0));

}

if (offset >= buffer->length_) {

return ThrowException(Exception::TypeError(String::New(

"Offset is out of bounds")));

}

const size_t size = base64_decoded_size(*s, s.length());

if (size > buffer->length_ - offset) {

// throw exception, don't silently truncate

return ThrowException(Exception::TypeError(String::New(

"Buffer too small")));

}

char a, b, c, d;

char* dst = buffer->data_ + offset;

const char *src = *s;

const char *const srcEnd = src + s.length();

while (src < srcEnd) {

const int remaining = srcEnd - src;

if (remaining == 0 || *src == '=') break;

a = unbase64_table[*src++];

if (remaining == 1 || *src == '=') break;

b = unbase64_table[*src++];

*dst++ = (a << 2) | ((b & 0x30) >> 4);

if (remaining == 2 || *src == '=') break;

c = unbase64_table[*src++];

*dst++ = ((b & 0x0F) << 4) | ((c & 0x3C) >> 2);

if (remaining == 3 || *src == '=') break;

d = unbase64_table[*src++];

*dst++ = ((c & 0x03) << 6) | (d & 0x3F);

}

return scope.Close(Integer::New(size));

}

Handle<Value> Buffer::BinaryWrite(const Arguments &args) {

HandleScope scope;

Buffer *buffer = ObjectWrap::Unwrap<Buffer>(args.This());

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

return ThrowException(Exception::TypeError(String::New(

"Argument must be a string")));

}

Local<String> s = args[0]->ToString();

size_t offset = args[1]->Int32Value();

if (s->Length() > 0 && offset >= buffer->length_) {

return ThrowException(Exception::TypeError(String::New(

"Offset is out of bounds")));

}

char *p = (char*)buffer->data_ + offset;

size_t towrite = MIN((unsigned long) s->Length(), buffer->length_ - offset);

int written = DecodeWrite(p, towrite, s, BINARY);

return scope.Close(Integer::New(written));

}

// var nbytes = Buffer.byteLength("string", "utf8")

Handle<Value> Buffer::ByteLength(const Arguments &args) {

HandleScope scope;

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

return ThrowException(Exception::TypeError(String::New(

"Argument must be a string")));

}

Local<String> s = args[0]->ToString();

enum encoding e = ParseEncoding(args[1], UTF8);

return scope.Close(Integer::New(node::ByteLength(s, e)));

}

Handle<Value> Buffer::MakeFastBuffer(const Arguments &args) {

HandleScope scope;

Buffer *buffer = ObjectWrap::Unwrap<Buffer>(args[0]->ToObject());

Local<Object> fast_buffer = args[1]->ToObject();;

uint32_t offset = args[2]->Uint32Value();

uint32_t length = args[3]->Uint32Value();

fast_buffer->SetIndexedPropertiesToPixelData((uint8_t*)buffer->data_ + offset,

length);

return Undefined();

}

bool Buffer::HasInstance(v8::Handle<v8::Value> val) {

if (!val->IsObject()) return false;

v8::Local<v8::Object> obj = val->ToObject();

if (obj->HasIndexedPropertiesInPixelData()) return true;

// Return true for "SlowBuffer"

if (constructor_template->HasInstance(obj)) return true;

return false;

}

void Buffer::Initialize(Handle<Object> target) {

HandleScope scope;

length_symbol = Persistent<String>::New(String::NewSymbol("length"));

chars_written_sym = Persistent<String>::New(String::NewSymbol("_charsWritten"));

Local<FunctionTemplate> t = FunctionTemplate::New(Buffer::New);

constructor_template = Persistent<FunctionTemplate>::New(t);

constructor_template->InstanceTemplate()->SetInternalFieldCount(1);

constructor_template->SetClassName(String::NewSymbol("SlowBuffer"));

// copy free

NODE_SET_PROTOTYPE_METHOD(constructor_template, "binarySlice", Buffer::BinarySlice);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "asciiSlice", Buffer::AsciiSlice);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "base64Slice", Buffer::Base64Slice);

// TODO NODE_SET_PROTOTYPE_METHOD(t, "utf16Slice", Utf16Slice);

// copy

NODE_SET_PROTOTYPE_METHOD(constructor_template, "utf8Slice", Buffer::Utf8Slice);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "utf8Write", Buffer::Utf8Write);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "asciiWrite", Buffer::AsciiWrite);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "binaryWrite", Buffer::BinaryWrite);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "base64Write", Buffer::Base64Write);

NODE_SET_PROTOTYPE_METHOD(constructor_template, "copy", Buffer::Copy);

NODE_SET_METHOD(constructor_template->GetFunction(),

"byteLength",

Buffer::ByteLength);

NODE_SET_METHOD(constructor_template->GetFunction(),

"makeFastBuffer",

Buffer::MakeFastBuffer);

target->Set(String::NewSymbol("SlowBuffer"), constructor_template->GetFunction());

}

} // namespace node

NODE_MODULE(node_buffer, node::Buffer::Initialize);

node/src/node_buffer.cc at b5359e40be91c113feef45ff4e1be65cffe337d0 · cnusbaum/node · GitHub

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