com.helger.security.mac

Class MacInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

com.helger.commons.io.stream.WrappedInputStream

com.helger.security.mac.MacInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class MacInputStream
extends com.helger.commons.io.stream.WrappedInputStream

A transparent stream that updates the associated Mac using the bits going through the stream.

To complete the Mac computation, call one of the doFinal methods on the associated Mac after your calls to one of this Mac input stream's read methods.

It is possible to turn this stream on or off (see on). When it is on, a call to one of the read methods results in an update on the Mac. But when it is off, the Mac is not updated. The default is for the stream to be on.

Note that Mac objects can compute only one digest (see Mac), so that in order to compute intermediate digests, a caller should retain a handle onto the Mac object, and clone it for each digest to be computed, leaving the original digest untouched.

Since:

9.1.7

Author:

Philip Helger

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	DEFAULT_ON

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
MacInputStream(InputStream aIS, Mac aMac) Creates a Mac input stream, using the specified input stream and Mac.

Method Summary

Modifier and Type	Method and Description
Mac	getMac() Returns the Mac associated with this stream.
boolean	isOn()
int	read() Reads a byte, and updates the Mac (if the function is on).
int	read(byte[] aBuf, int nOfs, int nLen) Reads into a byte array, and updates the Mac (if the function is on).
void	setMac(Mac aMac) Associates the specified Mac with this stream.
void	setOn(boolean bOn) Turns the function on or off.
String	toString()

Methods inherited from class com.helger.commons.io.stream.WrappedInputStream

getWrappedInputStream

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_ON

public static final boolean DEFAULT_ON

See Also:

Constant Field Values

Constructor Detail

MacInputStream

public MacInputStream(@Nonnull
                      InputStream aIS,
                      @Nonnull
                      Mac aMac)

Creates a Mac input stream, using the specified input stream and Mac.

Parameters:

aIS - the input stream.

aMac - the Mac to associate with this stream.

Method Detail

getMac

@Nonnull
public final Mac getMac()

Returns the Mac associated with this stream.

Returns:

the Mac associated with this stream.

See Also:

setMac(Mac)

setMac

public final void setMac(@Nonnull
                         Mac aMac)

Associates the specified Mac with this stream.

Parameters:

aMac - the Mac to be associated with this stream.

See Also:

getMac()

setOn

public final void setOn(boolean bOn)

Turns the function on or off. The default is on. When it is on, a call to one of the read methods results in an update on the Mac. But when it is off, the Mac is not updated.

Parameters:

bOn - true to turn the function on, false to turn it off.

isOn

public final boolean isOn()

Returns:

true if Mac processing is on, false if it is off

read

public int read()
         throws IOException

Reads a byte, and updates the Mac (if the function is on). That is, this method reads a byte from the input stream, blocking until the byte is actually read. If the function is on (see on), this method will then call update on the Mac associated with this stream, passing it the byte read.

Overrides:

read in class FilterInputStream

Returns:

the byte read.

Throws:

IOException - if an I/O error occurs.

See Also:

Mac.update(byte)

read

public int read(@Nonnull
                byte[] aBuf,
                @Nonnegative
                int nOfs,
                @Nonnegative
                int nLen)
         throws IOException

Reads into a byte array, and updates the Mac (if the function is on). That is, this method reads up to len bytes from the input stream into the array b, starting at offset off. This method blocks until the data is actually read. If the function is on (see on), this method will then call update on the Mac associated with this stream, passing it the data.

Overrides:

read in class FilterInputStream

Parameters:

aBuf - the array into which the data is read.

nOfs - the starting offset into b of where the data should be placed.

nLen - the maximum number of bytes to be read from the input stream into b, starting at offset off.

Returns:

the actual number of bytes read. This is less than len if the end of the stream is reached prior to reading len bytes. -1 is returned if no bytes were read because the end of the stream had already been reached when the call was made.

Throws:

IOException - if an I/O error occurs.

See Also:

Mac.update(byte[], int, int)

toString

public String toString()

Overrides:

toString in class com.helger.commons.io.stream.WrappedInputStream