| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.commons.io.input; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.RandomAccessFile; |
| import java.util.Objects; |
| |
| /** |
| * Streams data from a {@link RandomAccessFile} starting at its current position. |
| * |
| * @since 2.8.0 |
| */ |
| public class RandomAccessFileInputStream extends InputStream { |
| |
| private final boolean closeOnClose; |
| private final RandomAccessFile randomAccessFile; |
| |
| /** |
| * Constructs a new instance configured to leave the underlying file open when this stream is closed. |
| * |
| * @param file The file to stream. |
| */ |
| public RandomAccessFileInputStream(final RandomAccessFile file) { |
| this(file, false); |
| } |
| |
| /** |
| * Constructs a new instance. |
| * |
| * @param file The file to stream. |
| * @param closeOnClose Whether to close the underlying file when this stream is closed. |
| */ |
| public RandomAccessFileInputStream(final RandomAccessFile file, final boolean closeOnClose) { |
| this.randomAccessFile = Objects.requireNonNull(file, "file"); |
| this.closeOnClose = closeOnClose; |
| } |
| |
| /** |
| * Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream. |
| * |
| * If there are more than {@link Integer#MAX_VALUE} bytes available, return {@link Integer#MAX_VALUE}. |
| * |
| * @return An estimate of the number of bytes that can be read. |
| * @throws IOException If an I/O error occurs. |
| */ |
| @Override |
| public int available() throws IOException { |
| final long avail = availableLong(); |
| if (avail > Integer.MAX_VALUE) { |
| return Integer.MAX_VALUE; |
| } |
| return (int) avail; |
| } |
| |
| /** |
| * Returns the number of bytes that can be read (or skipped over) from this input stream. |
| * |
| * @return The number of bytes that can be read. |
| * @throws IOException If an I/O error occurs. |
| */ |
| public long availableLong() throws IOException { |
| return randomAccessFile.length() - randomAccessFile.getFilePointer(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| super.close(); |
| if (closeOnClose) { |
| randomAccessFile.close(); |
| } |
| } |
| |
| /** |
| * Gets the underlying file. |
| * |
| * @return the underlying file. |
| */ |
| public RandomAccessFile getRandomAccessFile() { |
| return randomAccessFile; |
| } |
| |
| /** |
| * Returns whether to close the underlying file when this stream is closed. |
| * |
| * @return Whether to close the underlying file when this stream is closed. |
| */ |
| public boolean isCloseOnClose() { |
| return closeOnClose; |
| } |
| |
| @Override |
| public int read() throws IOException { |
| return randomAccessFile.read(); |
| } |
| |
| @Override |
| public int read(final byte[] bytes) throws IOException { |
| return randomAccessFile.read(bytes); |
| } |
| |
| @Override |
| public int read(final byte[] bytes, final int offset, final int length) throws IOException { |
| return randomAccessFile.read(bytes, offset, length); |
| } |
| |
| /** |
| * Delegates to the underlying file. |
| * |
| * @param position See {@link RandomAccessFile#seek(long)}. |
| * @throws IOException See {@link RandomAccessFile#seek(long)}. |
| * @see RandomAccessFile#seek(long) |
| */ |
| private void seek(final long position) throws IOException { |
| randomAccessFile.seek(position); |
| } |
| |
| @Override |
| public long skip(final long skipCount) throws IOException { |
| if (skipCount <= 0) { |
| return 0; |
| } |
| final long filePointer = randomAccessFile.getFilePointer(); |
| final long fileLength = randomAccessFile.length(); |
| if (filePointer >= fileLength) { |
| return 0; |
| } |
| final long targetPos = filePointer + skipCount; |
| final long newPos = targetPos > fileLength ? fileLength - 1 : targetPos; |
| if (newPos > 0) { |
| seek(newPos); |
| } |
| return randomAccessFile.getFilePointer() - filePointer; |
| } |
| } |