在.NET中避免双重转换(byte []到字符串为单一)的方法？

Question

在低延迟HFT应用程序中,我有套接字接收Byte[]包含股票市场数据的消息.

在供应商协议中,股票价格字段Byte[]包含ASCII字符序列.
即字节序列[51-51-46-56]对应于ascii字符[3-3 -.- 8],等于33.8数字.

实际上在消息解析期间我转换Byte[]为字符串然后字符串为Single/float.

有没有办法避免这种双重转换并直接转换Byte[]为单个/浮点数？
其次是否有一种方法可以避免使用在.NET中效率低下的字符串类型(容易发生不可变垃圾收集)？

提前致谢.

问候

[编辑2019年]:这是3年来完美无缺的最终解决方案:

/// <summary> Read a Double precision float field in GL format from the stream and advances stream position of n (1 of field lenght flag + field lenght). </summary>
/// <returns>-1 in case of error, Double precision floating point value ROUNDED TO 8 DECIMAL PLACES in case of success </returns>
/// <param name="IniPos"> Initial Stream Position</param>
public double ReadGLFieldAsDouble(long IniPos = -1)
{
// --
if (IniPos >= 0)
    Strm.Position = IniPos;
int FLenght = Strm.ReadByte - 32; // case of "01000" SW Snapshot, field 7 doesn't exists, but in the message is a blank (32)
                                  // --early exit
if (FLenght <= 0)
    return -1; // a blank field (byte 32) returns -1
if (Strm.Length - Strm.Position < FLenght)
    return -1;
// --
double Dbl = 0;
int Cpos = -1;
int b = 0;
int sign = 1;

// --Builds as Integer with no point Separator
for (int i = 0; i < FLenght ; i++)
{
    b = Strm.ReadByte;
    switch (b)
    {
        case 45: // ASCII 45="-" sign
            {
                sign = -1;
                break;
            }

        case 46: // ASCII 46 is decimal point="." ; ASCII 44 is comma=","
            {
                Cpos = i; // decimal point position
                break;
            }

        default:
            {
                Dbl = Dbl * 10 + (b - 48); // increments as integer ASCII 48=0
                break;
            }
    }
}

// --Transforms in floating point  dividing by power of 10, multiplies by sign and returns
if (Cpos != -1)
    Dbl = (Dbl / (Math.Pow(10, (FLenght - 1 - Cpos))));
return Math.Round(sign * Dbl, 8);
}

Answer 1

 byte[] arr = new byte[] { 51, 51, 46, 56};
 double res = 0, floatindex = 0.1;
 bool isFraction = false;
 for (int i = 0; i < arr.Length; i++)
 {
    if (arr[i] == 46)
    {
        isFraction = true;
        continue;
    }

    if (!isFraction)
        res = 10*res + arr[i] - 48;
    else
    {
        res += (arr[i] - 48)*floatindex;
        floatindex /= 10.0;
    }
}
return res;

从文化的角度来看,它假设你总是有一个'点'来标记小数点的分隔(而不是像法国文化中那样的昏迷)