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buffer: move checkFloat from lib into src
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The type and range checks performed by this function can be done more
efficiently in native code.

PR-URL: #3763
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
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Matt Loring authored and rvagg committed Dec 5, 2015
1 parent f90227b commit fcf0e8e
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Showing 2 changed files with 42 additions and 29 deletions.
28 changes: 12 additions & 16 deletions lib/buffer.js
Original file line number Diff line number Diff line change
Expand Up @@ -1028,20 +1028,13 @@ Buffer.prototype.writeInt32BE = function(value, offset, noAssert) {
};


function checkFloat(buffer, value, offset, ext) {
if (!(buffer instanceof Buffer))
throw new TypeError('buffer must be a Buffer instance');
if (offset + ext > buffer.length)
throw new RangeError('index out of range');
}


Buffer.prototype.writeFloatLE = function writeFloatLE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 4);
binding.writeFloatLE(this, val, offset);
binding.writeFloatLE(this, val, offset);
else
binding.writeFloatLE(this, val, offset, true);
return offset + 4;
};

Expand All @@ -1050,8 +1043,9 @@ Buffer.prototype.writeFloatBE = function writeFloatBE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 4);
binding.writeFloatBE(this, val, offset);
binding.writeFloatBE(this, val, offset);
else
binding.writeFloatBE(this, val, offset, true);
return offset + 4;
};

Expand All @@ -1060,8 +1054,9 @@ Buffer.prototype.writeDoubleLE = function writeDoubleLE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 8);
binding.writeDoubleLE(this, val, offset);
binding.writeDoubleLE(this, val, offset);
else
binding.writeDoubleLE(this, val, offset, true);
return offset + 8;
};

Expand All @@ -1070,7 +1065,8 @@ Buffer.prototype.writeDoubleBE = function writeDoubleBE(val, offset, noAssert) {
val = +val;
offset = offset >>> 0;
if (!noAssert)
checkFloat(this, val, offset, 8);
binding.writeDoubleBE(this, val, offset);
binding.writeDoubleBE(this, val, offset);
else
binding.writeDoubleBE(this, val, offset, true);
return offset + 8;
};
43 changes: 30 additions & 13 deletions src/node_buffer.cc
Original file line number Diff line number Diff line change
Expand Up @@ -730,15 +730,37 @@ void ReadDoubleBE(const FunctionCallbackInfo<Value>& args) {


template <typename T, enum Endianness endianness>
uint32_t WriteFloatGeneric(const FunctionCallbackInfo<Value>& args) {
SPREAD_ARG(args[0], ts_obj);
void WriteFloatGeneric(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);

bool should_assert = args.Length() < 4;

if (should_assert) {
THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);
}

Local<Uint8Array> ts_obj = args[0].As<Uint8Array>();
ArrayBuffer::Contents ts_obj_c = ts_obj->Buffer()->GetContents();
const size_t ts_obj_offset = ts_obj->ByteOffset();
const size_t ts_obj_length = ts_obj->ByteLength();
char* const ts_obj_data =
static_cast<char*>(ts_obj_c.Data()) + ts_obj_offset;
if (ts_obj_length > 0)
CHECK_NE(ts_obj_data, nullptr);

T val = args[1]->NumberValue(env->context()).FromMaybe(0);
size_t offset = args[2]->IntegerValue(env->context()).FromMaybe(0);

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

if (should_assert) {
CHECK_NOT_OOB(offset + memcpy_num >= memcpy_num);
CHECK_NOT_OOB(offset + memcpy_num <= ts_obj_length);
}
CHECK_LE(offset + memcpy_num, ts_obj_length);

union NoAlias {
T val;
char bytes[sizeof(T)];
Expand All @@ -749,31 +771,26 @@ uint32_t WriteFloatGeneric(const FunctionCallbackInfo<Value>& args) {
if (endianness != GetEndianness())
Swizzle(na.bytes, sizeof(na.bytes));
memcpy(ptr, na.bytes, memcpy_num);
return offset + memcpy_num;
}


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


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