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using System;
using System.IO;
namespace Org.BouncyCastle.Utilities.Encoders
{
public class Base64Encoder
: IEncoder
{
protected readonly byte[] encodingTable =
{
(byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
(byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
(byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
(byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
(byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
(byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
(byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
(byte)'v',
(byte)'w', (byte)'x', (byte)'y', (byte)'z',
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6',
(byte)'7', (byte)'8', (byte)'9',
(byte)'+', (byte)'/'
};
protected byte padding = (byte)'=';
/*
* set up the decoding table.
*/
protected readonly byte[] decodingTable = new byte[128];
protected void InitialiseDecodingTable()
{
Arrays.Fill(decodingTable, (byte)0xff);
for (int i = 0; i < encodingTable.Length; i++)
{
decodingTable[encodingTable[i]] = (byte)i;
}
}
public Base64Encoder()
{
InitialiseDecodingTable();
}
public int Encode(byte[] inBuf, int inOff, int inLen, byte[] outBuf, int outOff)
{
int inPos = inOff;
int inEnd = inOff + inLen - 2;
int outPos = outOff;
while (inPos < inEnd)
{
uint a1 = inBuf[inPos++];
uint a2 = inBuf[inPos++];
uint a3 = inBuf[inPos++];
outBuf[outPos++] = encodingTable[(a1 >> 2) & 0x3F];
outBuf[outPos++] = encodingTable[((a1 << 4) | (a2 >> 4)) & 0x3F];
outBuf[outPos++] = encodingTable[((a2 << 2) | (a3 >> 6)) & 0x3F];
outBuf[outPos++] = encodingTable[a3 & 0x3F];
}
switch (inLen - (inPos - inOff))
{
case 1:
{
uint a1 = inBuf[inPos++];
outBuf[outPos++] = encodingTable[(a1 >> 2) & 0x3F];
outBuf[outPos++] = encodingTable[(a1 << 4) & 0x3F];
outBuf[outPos++] = padding;
outBuf[outPos++] = padding;
break;
}
case 2:
{
uint a1 = inBuf[inPos++];
uint a2 = inBuf[inPos++];
outBuf[outPos++] = encodingTable[(a1 >> 2) & 0x3F];
outBuf[outPos++] = encodingTable[((a1 << 4) | (a2 >> 4)) & 0x3F];
outBuf[outPos++] = encodingTable[(a2 << 2) & 0x3F];
outBuf[outPos++] = padding;
break;
}
}
return outPos - outOff;
}
/**
* encode the input data producing a base 64 output stream.
*
* @return the number of bytes produced.
*/
public int Encode(byte[] buf, int off, int len, Stream outStream)
{
if (len < 0)
return 0;
byte[] tmp = new byte[72];
int remaining = len;
while (remaining > 0)
{
int inLen = System.Math.Min(54, remaining);
int outLen = Encode(buf, off, inLen, tmp, 0);
outStream.Write(tmp, 0, outLen);
off += inLen;
remaining -= inLen;
}
return (len + 2) / 3 * 4;
}
private bool Ignore(char c)
{
return c == '\n' || c =='\r' || c == '\t' || c == ' ';
}
/**
* decode the base 64 encoded byte data writing it to the given output stream,
* whitespace characters will be ignored.
*
* @return the number of bytes produced.
*/
public int Decode(byte[] data, int off, int length, Stream outStream)
{
byte b1, b2, b3, b4;
byte[] outBuffer = new byte[54]; // S/MIME standard
int bufOff = 0;
int outLen = 0;
int end = off + length;
while (end > off)
{
if (!Ignore((char)data[end - 1]))
break;
end--;
}
int i = off;
int finish = end - 4;
i = NextI(data, i, finish);
while (i < finish)
{
b1 = decodingTable[data[i++]];
i = NextI(data, i, finish);
b2 = decodingTable[data[i++]];
i = NextI(data, i, finish);
b3 = decodingTable[data[i++]];
i = NextI(data, i, finish);
b4 = decodingTable[data[i++]];
if ((b1 | b2 | b3 | b4) >= 0x80)
throw new IOException("invalid characters encountered in base64 data");
outBuffer[bufOff++] = (byte)((b1 << 2) | (b2 >> 4));
outBuffer[bufOff++] = (byte)((b2 << 4) | (b3 >> 2));
outBuffer[bufOff++] = (byte)((b3 << 6) | b4);
if (bufOff == outBuffer.Length)
{
outStream.Write(outBuffer, 0, bufOff);
bufOff = 0;
}
outLen += 3;
i = NextI(data, i, finish);
}
if (bufOff > 0)
{
outStream.Write(outBuffer, 0, bufOff);
}
int e0 = NextI(data, i, end);
int e1 = NextI(data, e0 + 1, end);
int e2 = NextI(data, e1 + 1, end);
int e3 = NextI(data, e2 + 1, end);
outLen += DecodeLastBlock(outStream, (char)data[e0], (char)data[e1], (char)data[e2], (char)data[e3]);
return outLen;
}
private int NextI(
byte[] data,
int i,
int finish)
{
while ((i < finish) && Ignore((char)data[i]))
{
i++;
}
return i;
}
/**
* decode the base 64 encoded string data writing it to the given output stream,
* whitespace characters will be ignored.
*
* @return the number of bytes produced.
*/
public int DecodeString(string data, Stream outStream)
{
// Platform Implementation
// byte[] bytes = Convert.FromBase64String(data);
// outStream.Write(bytes, 0, bytes.Length);
// return bytes.Length;
byte b1, b2, b3, b4;
int length = 0;
int end = data.Length;
while (end > 0)
{
if (!Ignore(data[end - 1]))
break;
end--;
}
int i = 0;
int finish = end - 4;
i = NextI(data, i, finish);
while (i < finish)
{
b1 = decodingTable[data[i++]];
i = NextI(data, i, finish);
b2 = decodingTable[data[i++]];
i = NextI(data, i, finish);
b3 = decodingTable[data[i++]];
i = NextI(data, i, finish);
b4 = decodingTable[data[i++]];
if ((b1 | b2 | b3 | b4) >= 0x80)
throw new IOException("invalid characters encountered in base64 data");
outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4)));
outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2)));
outStream.WriteByte((byte)((b3 << 6) | b4));
length += 3;
i = NextI(data, i, finish);
}
length += DecodeLastBlock(outStream, data[end - 4], data[end - 3], data[end - 2], data[end - 1]);
return length;
}
private int DecodeLastBlock(
Stream outStream,
char c1,
char c2,
char c3,
char c4)
{
if (c3 == padding)
{
if (c4 != padding)
throw new IOException("invalid characters encountered at end of base64 data");
byte b1 = decodingTable[c1];
byte b2 = decodingTable[c2];
if ((b1 | b2) >= 0x80)
throw new IOException("invalid characters encountered at end of base64 data");
outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4)));
return 1;
}
if (c4 == padding)
{
byte b1 = decodingTable[c1];
byte b2 = decodingTable[c2];
byte b3 = decodingTable[c3];
if ((b1 | b2 | b3) >= 0x80)
throw new IOException("invalid characters encountered at end of base64 data");
outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4)));
outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2)));
return 2;
}
{
byte b1 = decodingTable[c1];
byte b2 = decodingTable[c2];
byte b3 = decodingTable[c3];
byte b4 = decodingTable[c4];
if ((b1 | b2 | b3 | b4) >= 0x80)
throw new IOException("invalid characters encountered at end of base64 data");
outStream.WriteByte((byte)((b1 << 2) | (b2 >> 4)));
outStream.WriteByte((byte)((b2 << 4) | (b3 >> 2)));
outStream.WriteByte((byte)((b3 << 6) | b4));
return 3;
}
}
private int NextI(string data, int i, int finish)
{
while ((i < finish) && Ignore(data[i]))
{
i++;
}
return i;
}
}
}
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