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  package org.bouncycastle.crypto.modes;
  
A wrapper class that allows block ciphers to be used to process data in a piecemeal fashion with PKCS5/PKCS7 padding. The PaddedBlockCipher outputs a block only when the buffer is full and more data is being added, or on a doFinal (unless the current block in the buffer is a pad block). The padding mechanism used is the one outlined in PKCS5/PKCS7.

Deprecated:
use org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher instead.
 
 public class PaddedBlockCipher
     extends BufferedBlockCipher
 {
    
Create a buffered block cipher with, or without, padding.

Parameters:
cipher the underlying block cipher this buffering object wraps.
 
     public PaddedBlockCipher(
         BlockCipher     cipher)
     {
         this. = cipher;
 
          = new byte[cipher.getBlockSize()];
          = 0;
     }

    
return the size of the output buffer required for an update plus a doFinal with an input of len bytes.

Parameters:
len the length of the input.
Returns:
the space required to accommodate a call to update and doFinal with len bytes of input.
 
     public int getOutputSize(
         int len)
     {
         int total       = len + ;
         int leftOver    = total % .;
 
         if (leftOver == 0)
         {
             if ()
             {
                 return total + .;
             }
 
             return total;
         }
 
         return total - leftOver + .;
     }

    
return the size of the output buffer required for an update an input of len bytes.

Parameters:
len the length of the input.
Returns:
the space required to accommodate a call to update with len bytes of input.
 
     public int getUpdateOutputSize(
         int len)
     {
         int total       = len + ;
         int leftOver    = total % .;
 
         if (leftOver == 0)
         {
             return total - .;
         }
 
         return total - leftOver;
     }

    
process a single byte, producing an output block if neccessary.

Parameters:
in the input byte.
out the space for any output that might be produced.
outOff the offset from which the output will be copied.
Throws:
org.bouncycastle.crypto.DataLengthException if there isn't enough space in out.
java.lang.IllegalStateException if the cipher isn't initialised.
 
     public int processByte(
         byte        in,
         byte[]      out,
         int         outOff)
         throws DataLengthExceptionIllegalStateException
     {
         int         resultLen = 0;
 
        if ( == .)
        {
            resultLen = .processBlock(, 0, outoutOff);
             = 0;
        }
        [++] = in;
        return resultLen;
    }

    
process an array of bytes, producing output if necessary.

Parameters:
in the input byte array.
inOff the offset at which the input data starts.
len the number of bytes to be copied out of the input array.
out the space for any output that might be produced.
outOff the offset from which the output will be copied.
Throws:
org.bouncycastle.crypto.DataLengthException if there isn't enough space in out.
java.lang.IllegalStateException if the cipher isn't initialised.
    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 blockSize   = getBlockSize();
        int length      = getUpdateOutputSize(len);
        
        if (length > 0)
        {
            if ((outOff + length) > out.length)
            {
                throw new DataLengthException("output buffer too short");
            }
        }
        int resultLen = 0;
        int gapLen = . - ;
        if (len > gapLen)
        {
            System.arraycopy(ininOffgapLen);
            resultLen += .processBlock(, 0, outoutOff);
             = 0;
            len -= gapLen;
            inOff += gapLen;
            while (len > .)
            {
                resultLen += .processBlock(ininOffoutoutOff + resultLen);
                len -= blockSize;
                inOff += blockSize;
            }
        }
        System.arraycopy(ininOfflen);
         += len;
        return resultLen;
    }

    
Process the last block in the buffer. If the buffer is currently full and padding needs to be added a call to doFinal will produce 2 * getBlockSize() bytes.

Parameters:
out the array the block currently being held is copied into.
outOff the offset at which the copying starts.
Throws:
org.bouncycastle.crypto.DataLengthException if there is insufficient space in out for the output or we are decrypting and the input is not block size aligned.
java.lang.IllegalStateException if the underlying cipher is not initialised.
org.bouncycastle.crypto.InvalidCipherTextException if padding is expected and not found.
    public int doFinal(
        byte[]  out,
        int     outOff)
    {
        int blockSize = .getBlockSize();
        int resultLen = 0;
        if ()
        {
            if ( == blockSize)
            {
                if ((outOff + 2 * blockSize) > out.length)
                {
                    throw new DataLengthException("output buffer too short");
                }
                resultLen = .processBlock(, 0, outoutOff);
                 = 0;
            }
            //
            // add PKCS7 padding
            //
            byte code = (byte)(blockSize - );
            while ( < blockSize)
            {
                [] = code;
                ++;
            }
            resultLen += .processBlock(, 0, outoutOff + resultLen);
        }
        else
        {
            if ( == blockSize)
            {
                resultLen = .processBlock(, 0, , 0);
                 = 0;
            }
            else
            {
                throw new DataLengthException("last block incomplete in decryption");
            }
            //
            // remove PKCS7 padding
            //
            int count = [blockSize - 1] & 0xff;
            if ((count < 0) || (count > blockSize))
            {
                throw new InvalidCipherTextException("pad block corrupted");
            }
            resultLen -= count;
            System.arraycopy(, 0, outoutOffresultLen);
        }
        reset();
        return resultLen;
    }
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