internal static string ToBase32StringSuitableForDirName(byte[] buff)
{
// This routine is optimised to be used with buffs of length 20
Debug.Assert(((buff.Length % 5) == 0), "Unexpected hash length");
StringBuilder sb = new StringBuilder();
byte b0, b1, b2, b3, b4;
int l, i;
l = buff.Length;
i = 0;
// Create l chars using the last 5 bits of each byte.
// Consume 3 MSB bits 5 bytes at a time.
do
{
b0 = (i < l) ? buff[i++] : (byte)0;
b1 = (i < l) ? buff[i++] : (byte)0;
b2 = (i < l) ? buff[i++] : (byte)0;
b3 = (i < l) ? buff[i++] : (byte)0;
b4 = (i < l) ? buff[i++] : (byte)0;
// Consume the 5 Least significant bits of each byte
sb.Append(s_base32Char[b0 & 0x1F]);
sb.Append(s_base32Char[b1 & 0x1F]);
sb.Append(s_base32Char[b2 & 0x1F]);
sb.Append(s_base32Char[b3 & 0x1F]);
sb.Append(s_base32Char[b4 & 0x1F]);
// Consume 3 MSB of b0, b1, MSB bits 6, 7 of b3, b4
sb.Append(s_base32Char[(
((b0 & 0xE0) >> 5) |
((b3 & 0x60) >> 2))]);
sb.Append(s_base32Char[(
((b1 & 0xE0) >> 5) |
((b4 & 0x60) >> 2))]);
// Consume 3 MSB bits of b2, 1 MSB bit of b3, b4
b2 >>= 5;
Debug.Assert(((b2 & 0xF8) == 0), "Unexpected set bits");
if ((b3 & 0x80) != 0)
b2 |= 0x08;
if ((b4 & 0x80) != 0)
b2 |= 0x10;
sb.Append(s_base32Char[b2]);
} while (i < l);
return sb.ToString();
}
