转帖：c#任意进制转换(2-36进制之间的转换)

转帖：c#任意进制转换(2-36进制之间的转换)

{ private static char[] rDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

public class AnyRadixConvert

/// <summary>
/// 将指定基数的数字的 System.String 表示形式转换为等效的 64 位有符号整数。
/// </summary>
/// <param name="value">包含数字的 System.String。</param>
/// <param name="fromBase">value 中数字的基数，它必须是[2,36]</param>
/// <returns>等效于 value 中的数字的 64 位有符号整数。- 或 - 如果 value 为 null，则为零。</returns>
private long x2h(string value, int fromBase)
{
value = value.Trim();
if (string.IsNullOrEmpty(value))
{
return 0L;
}

string sDigits = new string(rDigits, 0, fromBase);
long result = 0;
//value = reverse(value).ToUpper(); 1
value = value.ToUpper();// 2
for (int i = 0; i < value.Length; i++)
{
if (!sDigits.Contains(value[i].ToString()))
{
throw new ArgumentException(string.Format("The argument \"{0}\" is not in {1} system.", value[i], fromBase));
}
else
{
try
{
//result += (long)Math.Pow(fromBase, i) * getcharindex(rDigits, value[i]); 1
result += (long)Math.Pow(fromBase, i) * getcharindex(rDigits, value[value.Length - i - 1]);// 2
}
catch
{
throw new OverflowException("运算溢出.");
}
}
}

return result;
}

private int getcharindex(char[] arr, char value)
{
for (int i = 0; i < arr.Length; i++)
{
if (arr[i] == value)
{
return i;
}
}
return 0;
}

//long转化为toBase进制
private string h2x(long value, int toBase)
{
int digitIndex = 0;
long longPositive = Math.Abs(value);
int radix = toBase;
char[] outDigits = new char[63];

for (digitIndex = 0; digitIndex <= 64; digitIndex++)
{
if (longPositive == 0) { break; }

outDigits[outDigits.Length - digitIndex - 1] =
rDigits[longPositive % radix];
longPositive /= radix;
}

return new string(outDigits, outDigits.Length - digitIndex, digitIndex);
}

//任意进制转换,将fromBase进制表示的value转换为toBase进制
public string X2X(string value, int fromBase, int toBase)
{
if (string.IsNullOrEmpty(value.Trim()))
{
return string.Empty;
}

if (fromBase < 2 || fromBase > 36)
{
throw new ArgumentException(String.Format("The fromBase radix \"{0}\" is not in the range 2..36.", fromBase));
}

if (toBase < 2 || toBase > 36)
{
throw new ArgumentException(String.Format("The toBase radix \"{0}\" is not in the range 2..36.", toBase));
}

long m = x2h(value, fromBase);
string r = h2x(m, toBase);
return r;
}
}