org.bouncycastle.util.encoders.BufferedDecoder Maven / Gradle / Ivy
package org.bouncycastle.util.encoders;
/**
* A buffering class to allow translation from one format to another to
* be done in discrete chunks.
*/
public class BufferedDecoder
{
protected byte[] buf;
protected int bufOff;
protected Translator translator;
/**
* @param translator the translator to use.
* @param bufSize amount of input to buffer for each chunk.
*/
public BufferedDecoder(
Translator translator,
int bufSize)
{
this.translator = translator;
if ((bufSize % translator.getEncodedBlockSize()) != 0)
{
throw new IllegalArgumentException("buffer size not multiple of input block size");
}
buf = new byte[bufSize];
bufOff = 0;
}
public int processByte(
byte in,
byte[] out,
int outOff)
{
int resultLen = 0;
buf[bufOff++] = in;
if (bufOff == buf.length)
{
resultLen = translator.decode(buf, 0, buf.length, out, outOff);
bufOff = 0;
}
return resultLen;
}
public int processBytes(
byte[] in,
int inOff,
int len,
byte[] out,
int outOff)
{
if (len < 0)
{
throw new IllegalArgumentException("Can't have a negative input length!");
}
int resultLen = 0;
int gapLen = buf.length - bufOff;
if (len > gapLen)
{
System.arraycopy(in, inOff, buf, bufOff, gapLen);
resultLen += translator.decode(buf, 0, buf.length, out, outOff);
bufOff = 0;
len -= gapLen;
inOff += gapLen;
outOff += resultLen;
int chunkSize = len - (len % buf.length);
resultLen += translator.decode(in, inOff, chunkSize, out, outOff);
len -= chunkSize;
inOff += chunkSize;
}
if (len != 0)
{
System.arraycopy(in, inOff, buf, bufOff, len);
bufOff += len;
}
return resultLen;
}
}