freenet.crypt

Class ChecksumChecker

java.lang.Object

freenet.crypt.ChecksumChecker

Direct Known Subclasses:

CRCChecksumChecker

public abstract class ChecksumChecker
extends java.lang.Object

Simple utility to check and write checksums.

Field Summary

Fields

Modifier and Type	Field and Description
static int	CHECKSUM_CRC

Constructor Summary

Constructors

Constructor and Description
ChecksumChecker()

Method Summary

Modifier and Type	Method and Description
abstract byte[]	appendChecksum(byte[] data)
abstract boolean	checkChecksum(byte[] data, int offset, int length, byte[] checksum) Verify a checksum or report.
abstract int	checksumLength() Get the length of the checksum
java.io.InputStream	checksumReaderWithLength(java.io.InputStream dis, BucketFactory bf, long maxLength)
java.io.OutputStream	checksumWriter(java.io.OutputStream os)
abstract java.io.OutputStream	checksumWriter(java.io.OutputStream os, int skipPrefix) Get an OutputStream that will write a checksum when closed.
PrependLengthOutputStream	checksumWriterWithLength(java.io.OutputStream dos, BucketFactory bf) Get an OutputStream that will write to a temporary Bucket, append a checksum and prepend a length.
abstract void	copyAndStripChecksum(java.io.InputStream is, java.io.OutputStream os, long length) Copy bytes from one stream to another, verifying and stripping the final checksum.
static ChecksumChecker	create(int checksumID) Create a ChecksumChecker of the specified type.
byte[]	generateChecksum(byte[] bufToChecksum)
abstract byte[]	generateChecksum(byte[] bufToChecksum, int offset, int length)
abstract int	getChecksumTypeID()
int	lengthAndChecksumOverhead()
abstract void	readAndChecksum(java.io.DataInput is, byte[] buf, int offset, int length) Read from disk and verify the checksum that follows the data.
void	verifyChecksum(byte[] data, int offset, int length, byte[] checksum) Verify a checksum or throw
void	writeAndChecksum(java.io.ObjectOutputStream oos, byte[] buf)
void	writeAndChecksum(java.io.OutputStream os, byte[] buf, int offset, int length)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CHECKSUM_CRC

public static final int CHECKSUM_CRC

See Also:

Constant Field Values

Constructor Detail

ChecksumChecker

public ChecksumChecker()

Method Detail

checksumLength

public abstract int checksumLength()

Get the length of the checksum

checksumWriter

public abstract java.io.OutputStream checksumWriter(java.io.OutputStream os,
                                                    int skipPrefix)

Get an OutputStream that will write a checksum when closed. It will not close the underlying stream.

checksumWriter

public java.io.OutputStream checksumWriter(java.io.OutputStream os)

checksumWriterWithLength

public PrependLengthOutputStream checksumWriterWithLength(java.io.OutputStream dos,
                                                          BucketFactory bf)
                                                   throws java.io.IOException

Get an OutputStream that will write to a temporary Bucket, append a checksum and prepend a length.

Parameters:

os - The underlying stream, which will not be closed.

bf - Used to allocate temporary storage.

Throws:

java.io.IOException

appendChecksum

public abstract byte[] appendChecksum(byte[] data)

verifyChecksum

public void verifyChecksum(byte[] data,
                           int offset,
                           int length,
                           byte[] checksum)
                    throws ChecksumFailedException

Verify a checksum or throw

Throws:

ChecksumFailedException

checkChecksum

public abstract boolean checkChecksum(byte[] data,
                                      int offset,
                                      int length,
                                      byte[] checksum)

Verify a checksum or report.

Returns:

True if the checksum is correct, false otherwise.

generateChecksum

public abstract byte[] generateChecksum(byte[] bufToChecksum,
                                        int offset,
                                        int length)

generateChecksum

public byte[] generateChecksum(byte[] bufToChecksum)

getChecksumTypeID

public abstract int getChecksumTypeID()

copyAndStripChecksum

public abstract void copyAndStripChecksum(java.io.InputStream is,
                                          java.io.OutputStream os,
                                          long length)
                                   throws java.io.IOException,
                                          ChecksumFailedException

Copy bytes from one stream to another, verifying and stripping the final checksum.

Throws:

java.io.IOException

ChecksumFailedException

readAndChecksum

public abstract void readAndChecksum(java.io.DataInput is,
                                     byte[] buf,
                                     int offset,
                                     int length)
                              throws java.io.IOException,
                                     ChecksumFailedException

Read from disk and verify the checksum that follows the data. If it throws, the buffer will be zero'ed out.

Throws:

java.io.IOException

ChecksumFailedException

checksumReaderWithLength

public java.io.InputStream checksumReaderWithLength(java.io.InputStream dis,
                                                    BucketFactory bf,
                                                    long maxLength)
                                             throws java.io.IOException,
                                                    ChecksumFailedException

Throws:

java.io.IOException

ChecksumFailedException

writeAndChecksum

public void writeAndChecksum(java.io.OutputStream os,
                             byte[] buf,
                             int offset,
                             int length)
                      throws java.io.IOException

Throws:

java.io.IOException

writeAndChecksum

public void writeAndChecksum(java.io.ObjectOutputStream oos,
                             byte[] buf)
                      throws java.io.IOException

Throws:

java.io.IOException

lengthAndChecksumOverhead

public int lengthAndChecksumOverhead()

create

public static ChecksumChecker create(int checksumID)

Create a ChecksumChecker of the specified type.

Parameters:

checksumID - The checksum type.

Returns:

A ChecksumChecker of the given type.

Throws:

java.lang.IllegalArgumentException - If there is no ChecksumChecker for that ID.