| /* |
| * 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.pdfbox.io; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| |
| /** |
| * An interface allowing random access read operations. |
| */ |
| public interface RandomAccessRead extends Closeable |
| { |
| /** |
| * Read a single byte of data. |
| * |
| * @return The byte of data that is being read. |
| * |
| * @throws IOException If there is an error while reading the data. |
| */ |
| int read() throws IOException; |
| |
| /** |
| * Read a buffer of data. |
| * |
| * @param b The buffer to write the data to. |
| * @return The number of bytes that were actually read. |
| * @throws IOException If there was an error while reading the data. |
| */ |
| default int read(byte[] b) throws IOException |
| { |
| return read(b, 0, b.length); |
| } |
| |
| /** |
| * Read a buffer of data. |
| * |
| * @param b The buffer to write the data to. |
| * @param offset Offset into the buffer to start writing. |
| * @param length The amount of data to attempt to read. |
| * @return The number of bytes that were actually read. |
| * @throws IOException If there was an error while reading the data. |
| */ |
| int read(byte[] b, int offset, int length) throws IOException; |
| |
| /** |
| * Returns offset of next byte to be returned by a read method. |
| * |
| * @return offset of next byte which will be returned with next {@link #read()} |
| * (if no more bytes are left it returns a value >= length of source) |
| * |
| * @throws IOException |
| */ |
| long getPosition() throws IOException; |
| |
| /** |
| * Seek to a position in the data. |
| * |
| * @param position The position to seek to. |
| * @throws IOException If there is an error while seeking. |
| */ |
| void seek(long position) throws IOException; |
| |
| /** |
| * The total number of bytes that are available. |
| * |
| * @return The number of bytes available. |
| * |
| * @throws IOException If there is an IO error while determining the length of the data stream. |
| */ |
| long length() throws IOException; |
| |
| /** |
| * Returns true if this stream has been closed. |
| */ |
| boolean isClosed(); |
| |
| /** |
| * This will peek at the next byte. |
| * |
| * @return The next byte on the stream, leaving it as available to read. |
| * |
| * @throws IOException If there is an error reading the next byte. |
| */ |
| default int peek() throws IOException |
| { |
| int result = read(); |
| if (result != -1) |
| { |
| rewind(1); |
| } |
| return result; |
| } |
| |
| /** |
| * Seek backwards the given number of bytes. |
| * |
| * @param bytes the number of bytes to be seeked backwards |
| * @throws IOException If there is an error while seeking |
| */ |
| default void rewind(int bytes) throws IOException |
| { |
| seek(getPosition() - bytes); |
| } |
| |
| /** |
| * A simple test to see if we are at the end of the data. |
| * |
| * @return true if we are at the end of the data. |
| * |
| * @throws IOException If there is an error reading the next byte. |
| */ |
| boolean isEOF() throws IOException; |
| |
| /** |
| * Returns an estimate of the number of bytes that can be read. |
| * |
| * @return the number of bytes that can be read |
| * @throws IOException if this random access has been closed |
| */ |
| default int available() throws IOException |
| { |
| return (int) Math.min(length() - getPosition(), Integer.MAX_VALUE); |
| } |
| |
| /** |
| * Skips a given number of bytes. |
| * |
| * @param length the number of bytes to be skipped |
| * @throws IOException if an I/O error occurs while reading data |
| */ |
| default void skip(int length) throws IOException |
| { |
| seek(getPosition() + length); |
| } |
| |
| /** |
| * Creates a random access read view starting at the given position with the given length. |
| * |
| * @param startPosition start position within the underlying random access read |
| * @param streamLength stream length |
| * @return the random access read view |
| * @throws IOException if something went wrong when creating the view for the RandomAccessRead |
| * |
| */ |
| RandomAccessReadView createView(long startPosition, long streamLength) throws IOException; |
| } |