/*
* @(#)FileImageInputStream.java 1.21 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.imageio.stream;
import java.io.DataInput;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
/**
* An implementation of ImageInputStream
that gets its
* input from a File
or RandomAccessFile
.
* The file contents are assumed to be stable during the lifetime of
* the object.
*
* @version 0.5
*/
public class FileImageInputStream extends ImageInputStreamImpl {
private RandomAccessFile raf;
/**
* Constructs a FileImageInputStream
that will read
* from a given File
.
*
*
The file contents must not change between the time this
* object is constructed and the time of the last call to a read
* method.
*
* @param f a File
to read from.
*
* @exception IllegalArgumentException if f
is
* null
.
* @exception SecurityException if a security manager exists
* and does not allow read access to the file.
* @exception FileNotFoundException if f
is a
* directory or cannot be opened for reading for any other reason.
* @exception IOException if an I/O error occurs.
*/
public FileImageInputStream(File f)
throws FileNotFoundException, IOException {
if (f == null) {
throw new IllegalArgumentException("f == null!");
}
this.raf = new RandomAccessFile(f, "r");
}
/**
* Constructs a FileImageInputStream
that will read
* from a given RandomAccessFile
.
*
*
The file contents must not change between the time this
* object is constructed and the time of the last call to a read
* method.
*
* @param raf a RandomAccessFile
to read from.
*
* @exception IllegalArgumentException if raf
is
* null
.
*/
public FileImageInputStream(RandomAccessFile raf) {
if (raf == null) {
throw new IllegalArgumentException("raf == null!");
}
this.raf = raf;
}
public int read() throws IOException {
checkClosed();
bitOffset = 0;
int val = raf.read();
if (val != -1) {
++streamPos;
}
return val;
}
public int read(byte[] b, int off, int len) throws IOException {
checkClosed();
bitOffset = 0;
int nbytes = raf.read(b, off, len);
if (nbytes != -1) {
streamPos += nbytes;
}
return nbytes;
}
/**
* Returns the length of the underlying file, or -1
* if it is unknown.
*
* @return the file length as a long
, or
* -1
.
*/
public long length() {
try {
checkClosed();
return raf.length();
} catch (IOException e) {
return -1L;
}
}
public void seek(long pos) throws IOException {
checkClosed();
if (pos < flushedPos) {
throw new IndexOutOfBoundsException("pos < flushedPos!");
}
bitOffset = 0;
raf.seek(pos);
streamPos = raf.getFilePointer();
}
public void close() throws IOException {
super.close();
raf.close();
}
}