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493 lines (363 loc) · 14.2 KB
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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;
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
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 (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_));
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_ = 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 >= target->length()) {
return ThrowException(Exception::Error(String::New(
"targetStart out of bounds")));
}
if (source_start >= source->length()) {
return ThrowException(Exception::Error(String::New(
"sourceStart out of bounds")));
}
if (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;
s->Flatten();
int written = s->WriteUtf8((char*)p, buffer->length_ - offset);
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);
s->Flatten();
int written = s->WriteAscii((char*)p, 0, towrite);
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"));
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
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