update
This commit is contained in:
CroakFang
@@ -0,0 +1,228 @@
|
||||
using System;
|
||||
using System.Text;
|
||||
|
||||
namespace BaseNcoding
|
||||
{
|
||||
public class BaseN : Base
|
||||
{
|
||||
private readonly ulong[] _powN;
|
||||
|
||||
public uint BlockMaxBitsCount { get; }
|
||||
|
||||
public override bool HasSpecial => false;
|
||||
|
||||
public bool ReverseOrder { get; }
|
||||
|
||||
public BaseN(string alphabet, uint blockMaxBitsCount = 32,
|
||||
Encoding encoding = null, bool reverseOrder = false, bool parallel = false)
|
||||
: base((uint)alphabet.Length, alphabet, '\0', encoding, parallel)
|
||||
{
|
||||
BlockMaxBitsCount = blockMaxBitsCount;
|
||||
BlockBitsCount = GetOptimalBitsCount(CharsCount, out var charsCountInBits, blockMaxBitsCount);
|
||||
BlockCharsCount = (int)charsCountInBits;
|
||||
_powN = new ulong[BlockCharsCount];
|
||||
ulong pow = 1;
|
||||
for (int i = 0; i < BlockCharsCount - 1; i++)
|
||||
{
|
||||
_powN[BlockCharsCount - 1 - i] = pow;
|
||||
pow *= CharsCount;
|
||||
}
|
||||
_powN[0] = pow;
|
||||
ReverseOrder = reverseOrder;
|
||||
}
|
||||
|
||||
public override string Encode(byte[] data)
|
||||
{
|
||||
if (data == null || data.Length == 0)
|
||||
return "";
|
||||
|
||||
int mainBitsLength = data.Length * 8 / BlockBitsCount * BlockBitsCount;
|
||||
int tailBitsLength = data.Length * 8 - mainBitsLength;
|
||||
int mainCharsCount = mainBitsLength * BlockCharsCount / BlockBitsCount;
|
||||
int tailCharsCount = (tailBitsLength * BlockCharsCount + BlockBitsCount - 1) / BlockBitsCount;
|
||||
int totalCharsCount = mainCharsCount + tailCharsCount;
|
||||
int iterationCount = mainCharsCount / BlockCharsCount;
|
||||
|
||||
var result = new char[totalCharsCount];
|
||||
|
||||
if (!Parallel)
|
||||
{
|
||||
EncodeBlock(data, result, 0, iterationCount);
|
||||
}
|
||||
else
|
||||
{
|
||||
int processorCount = Math.Min(iterationCount, Environment.ProcessorCount);
|
||||
System.Threading.Tasks.Parallel.For(0, processorCount, i =>
|
||||
{
|
||||
int beginInd = i * iterationCount / processorCount;
|
||||
int endInd = (i + 1) * iterationCount / processorCount;
|
||||
EncodeBlock(data, result, beginInd, endInd);
|
||||
});
|
||||
}
|
||||
|
||||
if (tailBitsLength != 0)
|
||||
{
|
||||
ulong bits = GetBits64(data, mainBitsLength, tailBitsLength);
|
||||
BitsToChars(result, mainCharsCount, tailCharsCount, bits);
|
||||
}
|
||||
|
||||
return new string(result);
|
||||
}
|
||||
|
||||
public override byte[] Decode(string data)
|
||||
{
|
||||
if (string.IsNullOrEmpty(data))
|
||||
return new byte[0];
|
||||
|
||||
int totalBitsLength = ((data.Length - 1) * BlockBitsCount / BlockCharsCount + 8) / 8 * 8;
|
||||
int mainBitsLength = totalBitsLength / BlockBitsCount * BlockBitsCount;
|
||||
int tailBitsLength = totalBitsLength - mainBitsLength;
|
||||
int mainCharsCount = mainBitsLength * BlockCharsCount / BlockBitsCount;
|
||||
int tailCharsCount = (tailBitsLength * BlockCharsCount + BlockBitsCount - 1) / BlockBitsCount;
|
||||
ulong tailBits = CharsToBits(data, mainCharsCount, tailCharsCount);
|
||||
if (tailBits >> tailBitsLength != 0)
|
||||
{
|
||||
totalBitsLength += 8;
|
||||
mainBitsLength = totalBitsLength / BlockBitsCount * BlockBitsCount;
|
||||
tailBitsLength = totalBitsLength - mainBitsLength;
|
||||
mainCharsCount = mainBitsLength * BlockCharsCount / BlockBitsCount;
|
||||
tailCharsCount = (tailBitsLength * BlockCharsCount + BlockBitsCount - 1) / BlockBitsCount;
|
||||
}
|
||||
int iterationCount = mainCharsCount / BlockCharsCount;
|
||||
|
||||
byte[] result = new byte[totalBitsLength / 8];
|
||||
|
||||
if (!Parallel)
|
||||
{
|
||||
DecodeBlock(data, result, 0, iterationCount);
|
||||
}
|
||||
else
|
||||
{
|
||||
int processorCount = Math.Min(iterationCount, Environment.ProcessorCount);
|
||||
System.Threading.Tasks.Parallel.For(0, processorCount, i =>
|
||||
{
|
||||
int beginInd = i * iterationCount / processorCount;
|
||||
int endInd = (i + 1) * iterationCount / processorCount;
|
||||
DecodeBlock(data, result, beginInd, endInd);
|
||||
});
|
||||
}
|
||||
|
||||
if (tailCharsCount != 0)
|
||||
{
|
||||
ulong bits = CharsToBits(data, mainCharsCount, tailCharsCount);
|
||||
AddBits64(result, bits, mainBitsLength, tailBitsLength);
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
private void EncodeBlock(byte[] src, char[] dst, int beginInd, int endInd)
|
||||
{
|
||||
for (int ind = beginInd; ind < endInd; ind++)
|
||||
{
|
||||
int charInd = ind * BlockCharsCount;
|
||||
int bitInd = ind * BlockBitsCount;
|
||||
ulong bits = GetBits64(src, bitInd, BlockBitsCount);
|
||||
BitsToChars(dst, charInd, BlockCharsCount, bits);
|
||||
}
|
||||
}
|
||||
|
||||
private void DecodeBlock(string src, byte[] dst, int beginInd, int endInd)
|
||||
{
|
||||
for (int ind = beginInd; ind < endInd; ind++)
|
||||
{
|
||||
int charInd = ind * BlockCharsCount;
|
||||
int bitInd = ind * BlockBitsCount;
|
||||
ulong bits = CharsToBits(src, charInd, BlockCharsCount);
|
||||
AddBits64(dst, bits, bitInd, BlockBitsCount);
|
||||
}
|
||||
}
|
||||
|
||||
private static ulong GetBits64(byte[] data, int bitPos, int bitsCount)
|
||||
{
|
||||
ulong result = 0;
|
||||
|
||||
int currentBytePos = Math.DivRem(bitPos, 8, out int currentBitInBytePos);
|
||||
|
||||
int xLength = Math.Min(bitsCount, 8 - currentBitInBytePos);
|
||||
if (xLength != 0)
|
||||
{
|
||||
result = ((ulong)data[currentBytePos] << 56 + currentBitInBytePos) >> 64 - xLength << bitsCount - xLength;
|
||||
|
||||
currentBytePos += Math.DivRem(currentBitInBytePos + xLength, 8, out currentBitInBytePos);
|
||||
|
||||
int x2Length = bitsCount - xLength;
|
||||
if (x2Length > 8)
|
||||
x2Length = 8;
|
||||
|
||||
while (x2Length > 0)
|
||||
{
|
||||
xLength += x2Length;
|
||||
result |= (ulong)data[currentBytePos] >> 8 - x2Length << bitsCount - xLength;
|
||||
|
||||
currentBytePos += Math.DivRem(currentBitInBytePos + x2Length, 8, out currentBitInBytePos);
|
||||
|
||||
x2Length = bitsCount - xLength;
|
||||
if (x2Length > 8)
|
||||
x2Length = 8;
|
||||
}
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
private static void AddBits64(byte[] data, ulong value, int bitPos, int bitsCount)
|
||||
{
|
||||
unchecked
|
||||
{
|
||||
int currentBytePos = Math.DivRem(bitPos, 8, out int currentBitInBytePos);
|
||||
|
||||
int xLength = Math.Min(bitsCount, 8 - currentBitInBytePos);
|
||||
if (xLength != 0)
|
||||
{
|
||||
byte x1 = (byte)(value << 64 - bitsCount >> 56 + currentBitInBytePos);
|
||||
data[currentBytePos] |= x1;
|
||||
|
||||
currentBytePos += Math.DivRem(currentBitInBytePos + xLength, 8, out currentBitInBytePos);
|
||||
|
||||
int x2Length = bitsCount - xLength;
|
||||
if (x2Length > 8)
|
||||
x2Length = 8;
|
||||
|
||||
while (x2Length > 0)
|
||||
{
|
||||
xLength += x2Length;
|
||||
byte x2 = (byte)(value >> bitsCount - xLength << 8 - x2Length);
|
||||
data[currentBytePos] |= x2;
|
||||
|
||||
currentBytePos += Math.DivRem(currentBitInBytePos + x2Length, 8, out currentBitInBytePos);
|
||||
|
||||
x2Length = bitsCount - xLength;
|
||||
if (x2Length > 8)
|
||||
x2Length = 8;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private void BitsToChars(char[] chars, int ind, int count, ulong block)
|
||||
{
|
||||
ulong result = block;
|
||||
for (int i = 0; i < count; i++)
|
||||
{
|
||||
ulong quotient = result / CharsCount;
|
||||
ulong remainder = result - quotient * CharsCount;
|
||||
result = quotient;
|
||||
chars[ind + (!ReverseOrder ? i : count - 1 - i)] = Alphabet[(int)remainder];
|
||||
}
|
||||
}
|
||||
|
||||
private ulong CharsToBits(string data, int ind, int count)
|
||||
{
|
||||
ulong result = 0;
|
||||
for (int i = 0; i < count; i++)
|
||||
result += (ulong)InvAlphabet[data[ind + (!ReverseOrder ? i : count - 1 - i)]] * _powN[BlockCharsCount - 1 - i];
|
||||
return result;
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user