Skip to content

src: use DataView for B.{read,write}{Float,Double} #2897

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 1 commit into from
Closed

src: use DataView for B.{read,write}{Float,Double} #2897

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
28 changes: 20 additions & 8 deletions lib/buffer.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -291,6 +291,18 @@ function byteLength(string, encoding) {
Buffer.byteLength = byteLength;


Object.defineProperty(Buffer.prototype, 'dataView', {
enumerable: true,
get: function() {
if (this._dataView === undefined) {
this._dataView =
new DataView(this.buffer, this.byteOffset, this.byteLength);
}
return this._dataView;
}
});


// For backwards compatibility.
Object.defineProperty(Buffer.prototype, 'parent', {
enumerable: true,
Expand Down Expand Up @@ -744,31 +756,31 @@ Buffer.prototype.readFloatLE = function readFloatLE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return binding.readFloatLE(this, offset);
return this.dataView.getFloat32(offset, true);
};


Buffer.prototype.readFloatBE = function readFloatBE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 4, this.length);
return binding.readFloatBE(this, offset);
return this.dataView.getFloat32(offset);
};


Buffer.prototype.readDoubleLE = function readDoubleLE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 8, this.length);
return binding.readDoubleLE(this, offset);
return this.dataView.getFloat64(offset, true);
};


Buffer.prototype.readDoubleBE = function readDoubleBE(offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkOffset(offset, 8, this.length);
return binding.readDoubleBE(this, offset);
return this.dataView.getFloat64(offset);
};


Expand Down Expand Up @@ -991,7 +1003,7 @@ Buffer.prototype.writeFloatLE = function writeFloatLE(val, offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 4);
binding.writeFloatLE(this, val, offset);
this.dataView.setFloat32(offset, val, true);
return offset + 4;
};

Expand All @@ -1001,7 +1013,7 @@ Buffer.prototype.writeFloatBE = function writeFloatBE(val, offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 4);
binding.writeFloatBE(this, val, offset);
this.dataView.setFloat32(offset, val);
return offset + 4;
};

Expand All @@ -1011,7 +1023,7 @@ Buffer.prototype.writeDoubleLE = function writeDoubleLE(val, offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 8);
binding.writeDoubleLE(this, val, offset);
this.dataView.setFloat64(offset, val, true);
return offset + 8;
};

Expand All @@ -1021,6 +1033,6 @@ Buffer.prototype.writeDoubleBE = function writeDoubleBE(val, offset, noAssert) {
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 8);
binding.writeDoubleBE(this, val, offset);
this.dataView.setFloat64(offset, val);
return offset + 8;
};
109 changes: 0 additions & 109 deletions src/node_buffer.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -658,105 +658,6 @@ void AsciiWrite(const FunctionCallbackInfo<Value>& 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_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>
uint32_t WriteFloatGeneric(const FunctionCallbackInfo<Value>& args) {
SPREAD_ARG(args[0], ts_obj);

T val = args[1]->NumberValue();
uint32_t offset = args[2]->Uint32Value();
CHECK_LE(offset + sizeof(T), ts_obj_length);

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, sizeof(na.bytes));
return offset + sizeof(na.bytes);
}


void WriteFloatLE(const FunctionCallbackInfo<Value>& args) {
THROW_AND_RETURN_UNLESS_BUFFER(Environment::GetCurrent(args), args[0]);
args.GetReturnValue().Set(WriteFloatGeneric<float, kLittleEndian>(args));
}


void WriteFloatBE(const FunctionCallbackInfo<Value>& args) {
THROW_AND_RETURN_UNLESS_BUFFER(Environment::GetCurrent(args), args[0]);
args.GetReturnValue().Set(WriteFloatGeneric<float, kBigEndian>(args));
}


void WriteDoubleLE(const FunctionCallbackInfo<Value>& args) {
THROW_AND_RETURN_UNLESS_BUFFER(Environment::GetCurrent(args), args[0]);
args.GetReturnValue().Set(WriteFloatGeneric<double, kLittleEndian>(args));
}


void WriteDoubleBE(const FunctionCallbackInfo<Value>& args) {
THROW_AND_RETURN_UNLESS_BUFFER(Environment::GetCurrent(args), args[0]);
args.GetReturnValue().Set(WriteFloatGeneric<double, kBigEndian>(args));
}


void ByteLengthUtf8(const FunctionCallbackInfo<Value> &args) {
CHECK(args[0]->IsString());

Expand Down Expand Up @@ -962,16 +863,6 @@ void Initialize(Local<Object> target,
env->SetMethod(target, "indexOfNumber", IndexOfNumber);
env->SetMethod(target, "indexOfString", IndexOfString);

env->SetMethod(target, "readDoubleBE", ReadDoubleBE);
env->SetMethod(target, "readDoubleLE", ReadDoubleLE);
env->SetMethod(target, "readFloatBE", ReadFloatBE);
env->SetMethod(target, "readFloatLE", ReadFloatLE);

env->SetMethod(target, "writeDoubleBE", WriteDoubleBE);
env->SetMethod(target, "writeDoubleLE", WriteDoubleLE);
env->SetMethod(target, "writeFloatBE", WriteFloatBE);
env->SetMethod(target, "writeFloatLE", WriteFloatLE);

target->Set(env->context(),
FIXED_ONE_BYTE_STRING(env->isolate(), "kMaxLength"),
Integer::NewFromUnsigned(env->isolate(), kMaxLength)).FromJust();
Expand Down