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org.apache.poi.poifs.crypt
Class ChunkedCipherInputStream

java.lang.Object
  extended by java.io.InputStream
      extended by java.io.FilterInputStream
          extended by org.apache.poi.util.LittleEndianInputStream
              extended by org.apache.poi.poifs.crypt.ChunkedCipherInputStream
All Implemented Interfaces:
java.io.Closeable, LittleEndianInput
@Internal
public abstract class ChunkedCipherInputStream
extends LittleEndianInputStream

Field Summary
 
Fields inherited from class java.io.FilterInputStream
in
 
Constructor Summary
ChunkedCipherInputStream(java.io.InputStream stream, long size, int chunkSize)
           
ChunkedCipherInputStream(java.io.InputStream stream, long size, int chunkSize, int initialPos)
           
 
Method Summary
 int available()
           
protected  byte[] getChunk()
           
protected  int getChunkMask()
           
protected  byte[] getPlain()
           
 long getPos()
           
protected abstract  javax.crypto.Cipher initCipherForBlock(javax.crypto.Cipher existing, int block)
           
 javax.crypto.Cipher initCipherForBlock(int block)
           
protected  int invokeCipher(int totalBytes, boolean doFinal)
          Helper function for overriding the cipher invocation, i.e.
 void mark(int readlimit)
           
 boolean markSupported()
           
 int read()
           
 int read(byte[] b, int off, int len)
           
 void readPlain(byte[] b, int off, int len)
          Used when BIFF header fields (sid, size) are being read.
 void reset()
           
 void setNextRecordSize(int recordSize)
          Some ciphers (actually just XOR) are based on the record size, which needs to be set before decryption
 long skip(long n)
           
 
Methods inherited from class org.apache.poi.util.LittleEndianInputStream
readByte, readDouble, readFully, readFully, readInt, readLong, readShort, readUByte, readUInt, readUShort
 
Methods inherited from class java.io.FilterInputStream
close, read
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ChunkedCipherInputStream

public ChunkedCipherInputStream(java.io.InputStream stream,
                                long size,
                                int chunkSize)
                         throws java.security.GeneralSecurityException
Throws:
java.security.GeneralSecurityException

ChunkedCipherInputStream

public ChunkedCipherInputStream(java.io.InputStream stream,
                                long size,
                                int chunkSize,
                                int initialPos)
                         throws java.security.GeneralSecurityException
Throws:
java.security.GeneralSecurityException
Method Detail

initCipherForBlock

public final javax.crypto.Cipher initCipherForBlock(int block)
                                             throws java.io.IOException,
                                                    java.security.GeneralSecurityException
Throws:
java.io.IOException
java.security.GeneralSecurityException

initCipherForBlock

protected abstract javax.crypto.Cipher initCipherForBlock(javax.crypto.Cipher existing,
                                                          int block)
                                                   throws java.security.GeneralSecurityException
Throws:
java.security.GeneralSecurityException

read

public int read()
         throws java.io.IOException
Overrides:
read in class java.io.FilterInputStream
Throws:
java.io.IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException
Overrides:
read in class java.io.FilterInputStream
Throws:
java.io.IOException

skip

public long skip(long n)
          throws java.io.IOException
Overrides:
skip in class java.io.FilterInputStream
Throws:
java.io.IOException

available

public int available()
Specified by:
available in interface LittleEndianInput
Overrides:
available in class LittleEndianInputStream

markSupported

public boolean markSupported()
Overrides:
markSupported in class java.io.FilterInputStream

mark

public void mark(int readlimit)
Overrides:
mark in class java.io.FilterInputStream

reset

public void reset()
           throws java.io.IOException
Overrides:
reset in class java.io.FilterInputStream
Throws:
java.io.IOException

getChunkMask

protected int getChunkMask()

invokeCipher

protected int invokeCipher(int totalBytes,
                           boolean doFinal)
                    throws java.security.GeneralSecurityException
Helper function for overriding the cipher invocation, i.e. XOR doesn't use a cipher and uses it's own implementation

Throws:
javax.crypto.BadPaddingException
javax.crypto.IllegalBlockSizeException
javax.crypto.ShortBufferException
java.security.GeneralSecurityException

readPlain

public void readPlain(byte[] b,
                      int off,
                      int len)
Used when BIFF header fields (sid, size) are being read. The internal Cipher instance must step even when unencrypted bytes are read

Specified by:
readPlain in interface LittleEndianInput
Overrides:
readPlain in class LittleEndianInputStream
Parameters:
b - the byte array to receive the bytes
off - the start offset into the byte array
len - the amount of bytes to fill

setNextRecordSize

public void setNextRecordSize(int recordSize)
Some ciphers (actually just XOR) are based on the record size, which needs to be set before decryption

Parameters:
recordSize - the size of the next record

getChunk

protected byte[] getChunk()
Returns:
the chunk bytes

getPlain

protected byte[] getPlain()
Returns:
the plain bytes

getPos

public long getPos()
Returns:
the absolute position in the stream
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