/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.io;
import com.google.common.annotations.Beta;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* An {@link InputStream} that counts the number of bytes read.
*
* @author Chris Nokleberg
* @since 1.0
*/
@Beta
public final class CountingInputStream extends FilterInputStream {
private long count;
private long mark = -1;
/**
* Wraps another input stream, counting the number of bytes read.
*
* @param in the input stream to be wrapped
*/
public CountingInputStream(InputStream in) {
super(in);
}
/** Returns the number of bytes read. */
public long getCount() {
return count;
}
@Override public int read() throws IOException {
int result = in.read();
if (result != -1) {
count++;
}
return result;
}
@Override public int read(byte[] b, int off, int len) throws IOException {
int result = in.read(b, off, len);
if (result != -1) {
count += result;
}
return result;
}
@Override public long skip(long n) throws IOException {
long result = in.skip(n);
count += result;
return result;
}
@Override public void mark(int readlimit) {
in.mark(readlimit);
mark = count;
// it's okay to mark even if mark isn't supported, as reset won't work
}
@Override public void reset() throws IOException {
if (!in.markSupported()) {
throw new IOException("Mark not supported");
}
if (mark == -1) {
throw new IOException("Mark not set");
}
in.reset();
count = mark;
}
}
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