node/src/node_buffer.cc at master · blowery/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;

// Each javascript Buffer object is backed by a Blob object.

// the Blob is just a C-level chunk of bytes.

// It has a reference count.

struct Blob_ {

unsigned int refs;

size_t length;

char *data;

};

typedef struct Blob_ Blob;

static inline Blob * blob_new(size_t length) {

Blob * blob = (Blob*) malloc(sizeof(Blob));

if (!blob) return NULL;

blob->data = (char*) malloc(length);

if (!blob->data) {

free(blob);

return NULL;

}

V8::AdjustAmountOfExternalAllocatedMemory(sizeof(Blob) + length);

blob->length = length;

blob->refs = 0;

return blob;

}

static inline void blob_ref(Blob *blob) {

blob->refs++;

}

static inline void blob_unref(Blob *blob) {

assert(blob->refs > 0);

if (--blob->refs == 0) {

//fprintf(stderr, "free %d bytes\n", blob->length);

V8::AdjustAmountOfExternalAllocatedMemory(-(sizeof(Blob) + blob->length));

free(blob->data);

free(blob);

}

#if 0

// When someone calls buffer.asciiSlice, data is not copied. Instead V8

// references in the underlying Blob with this ExternalAsciiStringResource.

class AsciiSliceExt: public String::ExternalAsciiStringResource {

friend class Buffer;

public:

AsciiSliceExt(Buffer *parent, size_t start, size_t end) {

blob_ = parent->blob();

blob_ref(blob_);

assert(start <= end);

length_ = end - start;

assert(start + length_ <= parent->length());

data_ = parent->data() + start;

}

~AsciiSliceExt() {

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

blob_unref(blob_);

}

const char* data() const { return data_; }

size_t length() const { return length_; }

private:

const char *data_;

size_t length_;

Blob *blob_;

};

#endif

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);

}

Handle<Value> Buffer::New(const Arguments &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 if (args[0]->IsArray()) {

Local<Array> a = Local<Array>::Cast(args[0]);

buffer = new Buffer(a->Length());

char *p = buffer->data();

for (int i = 0; i < a->Length(); i++) {

p[i] = a->Get(i)->Uint32Value();

}

} else if (args[0]->IsString()) {

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

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

int length = e == UTF8 ? s->Utf8Length() : s->Length();

buffer = new Buffer(length);

} else if (Buffer::HasInstance(args[0]) && args.Length() > 2) {

// var slice = new Buffer(buffer, 123, 130);

// args: parent, start, end

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

SLICE_ARGS(args[1], args[2])

buffer = new Buffer(parent, start, end);

} 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_));

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

if (write_sym.IsEmpty()) {

write_sym = Persistent<String>::New(String::NewSymbol("write"));

}

Local<Value> write_v = args.This()->Get(write_sym);

assert(write_v->IsFunction());

Local<Function> write = Local<Function>::Cast(write_v);

Local<Value> argv[2] = { args[0], args[1] };

TryCatch try_catch;

write->Call(args.This(), 2, argv);

if (try_catch.HasCaught()) {

FatalException(try_catch);

}

return args.This();

}

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

blob_ = blob_new(length);

off_ = 0;

length_ = length;

blob_ref(blob_);

V8::AdjustAmountOfExternalAllocatedMemory(sizeof(Buffer));

}

Buffer::Buffer(Buffer *parent, size_t start, size_t end) : ObjectWrap() {

blob_ = parent->blob_;

assert(blob_->refs > 0);

blob_ref(blob_);

assert(start <= end);

off_ = parent->off_ + start;

length_ = end - start;

assert(length_ <= parent->length_);

V8::AdjustAmountOfExternalAllocatedMemory(sizeof(Buffer));

}

Buffer::~Buffer() {

assert(blob_->refs > 0);

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

blob_unref(blob_);

V8::AdjustAmountOfExternalAllocatedMemory(-static_cast<long int>(sizeof(Buffer)));

}

char* Buffer::data() {

return blob_->data + off_;

}

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

HandleScope scope;

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

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

const char *data = const_cast<char*>(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])

#if 0

AsciiSliceExt *ext = new AsciiSliceExt(parent, start, end);

Local<String> string = String::NewExternal(ext);

// There should be at least two references to the blob now - the parent

// and the slice.

assert(parent->blob_->refs >= 2);

#endif

const char *data = const_cast<char*>(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])

const char *data = const_cast<char*>(parent->data() + start);

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

return scope.Close(string);

}

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

HandleScope scope;

Local<Value> argv[3] = { args.This(), args[0], args[1] };

Local<Object> slice =

constructor_template->GetFunction()->NewInstance(3, argv);

return scope.Close(slice);

}

// 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")));

}

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(source_end - source_start,

target->length() - target_start);

memcpy((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);

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]->Int32Value();

if (offset >= buffer->length_) {

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

"Offset is out of bounds")));

}

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

int char_written;

int written = s->WriteUtf8((char*)p,

buffer->length_ - offset,

&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 (offset >= buffer->length_) {

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

"Offset is out of bounds")));

}

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

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

int written = s->WriteAscii((char*)p, 0, towrite, String::HINT_MANY_WRITES_EXPECTED);

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

}

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 (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));

}

// buffer.unpack(format, index);

// Starting at 'index', unpacks binary from the buffer into an array.

// 'format' is a string

// FORMAT RETURNS

// N uint32_t a 32bit unsigned integer in network byte order

// n uint16_t a 16bit unsigned integer in network byte order

// o uint8_t a 8bit unsigned integer

Handle<Value> Buffer::Unpack(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")));

}

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

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

#define OUT_OF_BOUNDS ThrowException(Exception::Error(String::New("Out of bounds")))

Local<Array> array = Array::New(format.length());

uint8_t uint8;

uint16_t uint16;

uint32_t uint32;

for (int i = 0; i < format.length(); i++) {

switch ((*format)[i]) {

// 32bit unsigned integer in network byte order

case 'N':

if (index + 3 >= buffer->length_) return OUT_OF_BOUNDS;

uint32 = htonl(*(uint32_t*)(buffer->data() + index));

array->Set(Integer::New(i), Integer::NewFromUnsigned(uint32));

index += 4;

break;

// 16bit unsigned integer in network byte order

case 'n':

if (index + 1 >= buffer->length_) return OUT_OF_BOUNDS;

uint16 = htons(*(uint16_t*)(buffer->data() + index));

array->Set(Integer::New(i), Integer::NewFromUnsigned(uint16));

index += 2;

break;

// a single octet, unsigned.

case 'o':

if (index >= buffer->length_) return OUT_OF_BOUNDS;

uint8 = (uint8_t)buffer->data()[index];

array->Set(Integer::New(i), Integer::NewFromUnsigned(uint8));

index += 1;

break;

default:

return ThrowException(Exception::Error(

String::New("Unknown format character")));

}

return scope.Close(array);

}

// 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);

Local<Integer> length =

Integer::New(e == UTF8 ? s->Utf8Length() : s->Length());

return scope.Close(length);

}

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("Buffer"));

// 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, "slice", Buffer::Slice);

// 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, "unpack", Buffer::Unpack);

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

NODE_SET_METHOD(constructor_template->GetFunction(),

"byteLength",

Buffer::ByteLength);

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

}

} // namespace node

node/src/node_buffer.cc at master · blowery/node · GitHub

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