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/*
* de.unkrig.commons - A general-purpose Java class library
*
* Copyright (c) 2011, Arno Unkrig
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
* following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package de.unkrig.commons.io;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import de.unkrig.commons.nullanalysis.NotNullByDefault;
/**
* A drop-in replacement for {@link java.io.FileInputStream} that supports {@link InputStream#mark(int) mark(int)} and
* {@link InputStream#reset() reset()}.
*
* Typically more efficient than {@code new BufferedInputStream(new FileInputstream(...))}.
*/
@NotNullByDefault(false) public
class MarkableFileInputStream extends InputStream {
private final RandomAccessFile randomAccessFile;
private long mark;
public
MarkableFileInputStream(String name) throws FileNotFoundException {
this(new File(name));
}
public
MarkableFileInputStream(File file) throws FileNotFoundException {
this.randomAccessFile = new RandomAccessFile(file, "r");
}
@Override public int
read() throws IOException {
return this.randomAccessFile.read();
}
@Override public int
read(byte[] b, int off, int len) throws IOException {
return this.randomAccessFile.read(b, off, len);
}
@Override public long
skip(long n) throws IOException {
long result = 0;
while (n > Integer.MAX_VALUE) {
int tmp = this.randomAccessFile.skipBytes(Integer.MAX_VALUE);
n -= tmp;
result += tmp;
}
result += this.randomAccessFile.skipBytes((int) n);
return result;
}
@Override public int
available() throws IOException {
return (int) Math.min(
Integer.MAX_VALUE,
this.randomAccessFile.length() - this.randomAccessFile.getFilePointer()
);
}
@Override public void
close() throws IOException { this.randomAccessFile.close(); }
@Override public synchronized void
mark(int readlimit) {
try {
this.mark = this.randomAccessFile.getFilePointer();
} catch (IOException ioe) {
throw new RuntimeException(ioe);
}
}
@Override public synchronized void
reset() throws IOException { this.randomAccessFile.seek(this.mark); }
@Override public boolean
markSupported() { return true; }
}