content: /*
   * Copyright (C) 2020 ActiveJ LLC.
   *
   * 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 io.activej.fs.util;
  
  import java.io.IOException;
  import java.io.InputStream;
  
  @SuppressWarnings("NullableProblems")
  public final class LimitedInputStream extends InputStream {
  	private final InputStream peer;
  	private long remaining;
  
  	public LimitedInputStream(InputStream peer, long maxBytes) {
  		this.peer = peer;
  		remaining = Math.max(maxBytes, 0);
  	}
  
  	@Override
  	public int available() throws IOException {
  		return (int) Math.min(peer.available(), remaining);
  	}
  
  	@Override
  	public void close() throws IOException {
  		peer.close();
  	}
  
  	@Override
  	public int read(byte[] buf, int off, int len) throws IOException {
  		if (remaining > 0) {
  			int nRead = peer.read(
  				buf, off, (int) Math.min(len, remaining));
  
  			remaining -= nRead;
  
  			return nRead;
  		} else {
  			return -1;
  		}
  	}
  
  	@Override
  	public int read(byte[] buf) throws IOException {
  		return this.read(buf, 0, buf.length);
  	}
  
  	@Override
  	public long skip(long n) throws IOException {
  		long skipped = peer.skip(Math.min(n, remaining));
  
  		remaining -= skipped;
  
  		return skipped;
  	}
  
  	@Override
  	public int read() throws IOException {
  		if (remaining > 0) {
  			int c = peer.read();
  
  			if (c >= 0) {
  				remaining -= 1;
  			}
  
  			return c;
  		} else {
  			return -1;
  		}
  	}
  }
  