CroakFang
100 lines
2.0 KiB
C#
100 lines
2.0 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Text;
|
|
|
|
namespace BaseNcoding
|
|
{
|
|
public class Base91 : Base
|
|
{
|
|
public const string DefaultAlphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~\"";
|
|
public const char DefaultSpecial = (char)0;
|
|
|
|
public override bool HasSpecial => false;
|
|
|
|
public Base91(string alphabet = DefaultAlphabet, char special = DefaultSpecial, Encoding textEncoding = null)
|
|
: base(91, alphabet, special, textEncoding)
|
|
{
|
|
BlockBitsCount = 13;
|
|
BlockCharsCount = 2;
|
|
}
|
|
|
|
public override string Encode(byte[] data)
|
|
{
|
|
StringBuilder result = new StringBuilder(data.Length);
|
|
|
|
int ebq = 0, en = 0;
|
|
for (int i = 0; i < data.Length; ++i)
|
|
{
|
|
ebq |= (data[i] & 255) << en;
|
|
en += 8;
|
|
if (en > 13)
|
|
{
|
|
int ev = ebq & 8191;
|
|
|
|
if (ev > 88)
|
|
{
|
|
ebq >>= 13;
|
|
en -= 13;
|
|
}
|
|
else
|
|
{
|
|
ev = ebq & 16383;
|
|
ebq >>= 14;
|
|
en -= 14;
|
|
}
|
|
|
|
int quotient = Math.DivRem(ev, 91, out int remainder);
|
|
result.Append(Alphabet[remainder]);
|
|
result.Append(Alphabet[quotient]);
|
|
}
|
|
}
|
|
|
|
if (en > 0)
|
|
{
|
|
int quotient = Math.DivRem(ebq, 91, out int remainder);
|
|
result.Append(Alphabet[remainder]);
|
|
if (en > 7 || ebq > 90)
|
|
result.Append(Alphabet[quotient]);
|
|
}
|
|
|
|
return result.ToString();
|
|
}
|
|
|
|
public override byte[] Decode(string data)
|
|
{
|
|
unchecked
|
|
{
|
|
int dbq = 0, dn = 0, dv = -1;
|
|
|
|
List<byte> result = new List<byte>(data.Length);
|
|
for (int i = 0; i < data.Length; ++i)
|
|
{
|
|
if (InvAlphabet[data[i]] == -1)
|
|
continue;
|
|
if (dv == -1)
|
|
dv = InvAlphabet[data[i]];
|
|
else
|
|
{
|
|
dv += InvAlphabet[data[i]] * 91;
|
|
dbq |= dv << dn;
|
|
dn += (dv & 8191) > 88 ? 13 : 14;
|
|
do
|
|
{
|
|
result.Add((byte)dbq);
|
|
dbq >>= 8;
|
|
dn -= 8;
|
|
}
|
|
while (dn > 7);
|
|
dv = -1;
|
|
}
|
|
}
|
|
|
|
if (dv != -1)
|
|
result.Add((byte)(dbq | dv << dn));
|
|
|
|
return result.ToArray();
|
|
}
|
|
}
|
|
}
|
|
}
|