将浮点数转换为字节[4]然后再转换为“浮点数”的最佳方法是什么？
我在C#.NET Micro Framework中这样做,所以我没有可用的BitConverter.
解决方法
我已经修改了
a Netduino implementation的BitConverter类以允许字节序规范(它不是“最佳方式”,但它可以工作).如果通过网络发送字节数组,我会使用BigEndian.只是提醒一下,NETMF不正式支持不安全.
using System;
using System.Diagnostics;
namespace netduino
{
public static class BitConverter
{
public static byte[] GetBytes(uint value)
{
return new byte[4] {
(byte)(value & 0xFF),(byte)((value >> 8) & 0xFF),(byte)((value >> 16) & 0xFF),(byte)((value >> 24) & 0xFF) };
}
public static unsafe byte[] GetBytes(float value)
{
uint val = *((uint*)&value);
return GetBytes(val);
}
public static unsafe byte[] GetBytes(float value,ByteOrder order)
{
byte[] bytes = GetBytes(value);
if (order != ByteOrder.LittleEndian)
{
System.Array.Reverse(bytes);
}
return bytes;
}
public static uint ToUInt32(byte[] value,int index)
{
return (uint)(
value[0 + index] << 0 |
value[1 + index] << 8 |
value[2 + index] << 16 |
value[3 + index] << 24);
}
public static unsafe float ToSingle(byte[] value,int index)
{
uint i = ToUInt32(value,index);
return *(((float*)&i));
}
public static unsafe float ToSingle(byte[] value,int index,ByteOrder order)
{
if (order != ByteOrder.LittleEndian)
{
System.Array.Reverse(value,index,value.Length);
}
return ToSingle(value,index);
}
public enum ByteOrder
{
LittleEndian,BigEndian
}
static public bool IsLittleEndian
{
get
{
unsafe
{
int i = 1;
char* p = (char*)&i;
return (p[0] == 1);
}
}
}
}
}
namespace BitConverterTest
{
class Program
{
static void Main(string[] args)
{
byte[] msbFirst = new byte[] { 0x42,0xF6,0xE9,0xE0 };
byte[] lsbFirst = new byte[] { 0xE0,0x42 };
const float f = 123.456789F;
byte[] b = netduino.BitConverter.GetBytes(f,netduino.BitConverter.ByteOrder.BigEndian);
for (int i = 0; i < b.Length; i++)
{
Debug.Assert(msbFirst[i] == b[i],"BitConverter.GetBytes(float,BigEndian) i=" + i);
}
Debug.Assert(f == netduino.BitConverter.ToSingle(msbFirst,netduino.BitConverter.ByteOrder.BigEndian));
Console.WriteLine("All tests passed");
Console.ReadKey();
}
}
}
