update

2022-12-13 22:47:31 +08:00
parent 9e7b10c1a5
commit df178687ba
40 changed files with 5401 additions and 15 deletions
@@ -0,0 +1,99 @@
+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();
+			}
+		}
+	}
+}