buffer: move checkFloat from lib into src

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>

Author: Matt Loring

lib/buffer.js

@@ -1028,20 +1028,13 @@ Buffer.prototype.writeInt32BE = function(value, offset, noAssert) {
 };
 
 
-functioncheckFloat(buffer,value,offset,ext){
-if(!(bufferinstanceofBuffer))
-thrownewTypeError('"buffer" argument must be a Buffer instance');
-if(offset+ext>buffer.length)
-thrownewRangeError('Index out of range');
-}
-
-
 Buffer.prototype.writeFloatLE=functionwriteFloatLE(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);
 returnoffset+4;
 };
 
@@ -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);
 returnoffset+4;
 };
 
@@ -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);
 returnoffset+8;
 };
 
@@ -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);
 returnoffset+8;
 };

src/node_buffer.cc

@@ -730,15 +730,37 @@ void ReadDoubleBE(const FunctionCallbackInfo<Value>& args) {
 
 
 template <typename T, enum Endianness endianness>
-uint32_tWriteFloatGeneric(const FunctionCallbackInfo<Value>& args) {
-SPREAD_ARG(args[0], ts_obj);
+voidWriteFloatGeneric(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();
+constsize_t ts_obj_offset = ts_obj->ByteOffset();
+constsize_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)];
@@ -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;
 }
 
 
 voidWriteFloatLE(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);
 }
 
 
 voidWriteFloatBE(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);
 }
 
 
 voidWriteDoubleLE(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);
 }
 
 
 voidWriteDoubleBE(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);
 }