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package org.spongycastle.util.encoders;
/**
* Converters for going from hex to binary and back. Note: this class assumes ASCII processing.
*/
public class HexTranslator
implements Translator
{
private static final byte[] hexTable =
{
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
(byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f'
};
/**
* size of the output block on encoding produced by getDecodedBlockSize()
* bytes.
*/
public int getEncodedBlockSize()
{
return 2;
}
public int encode(
byte[] in,
int inOff,
int length,
byte[] out,
int outOff)
{
for (int i = 0, j = 0; i < length; i++, j += 2)
{
out[outOff + j] = hexTable[(in[inOff] >> 4) & 0x0f];
out[outOff + j + 1] = hexTable[in[inOff] & 0x0f];
inOff++;
}
return length * 2;
}
/**
* size of the output block on decoding produced by getEncodedBlockSize()
* bytes.
*/
public int getDecodedBlockSize()
{
return 1;
}
public int decode(
byte[] in,
int inOff,
int length,
byte[] out,
int outOff)
{
int halfLength = length / 2;
byte left, right;
for (int i = 0; i < halfLength; i++)
{
left = in[inOff + i * 2];
right = in[inOff + i * 2 + 1];
if (left < (byte)'a')
{
out[outOff] = (byte)((left - '0') << 4);
}
else
{
out[outOff] = (byte)((left - 'a' + 10) << 4);
}
if (right < (byte)'a')
{
out[outOff] += (byte)(right - '0');
}
else
{
out[outOff] += (byte)(right - 'a' + 10);
}
outOff++;
}
return halfLength;
}
}
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