    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.imaging.bytesource;
    018
    019import java.io.File;
    020import java.io.IOException;
    021import java.io.InputStream;
    022import java.nio.file.Path;
    023import java.util.Objects;
    024
    025import org.apache.commons.imaging.common.BinaryFunctions;
    026import org.apache.commons.io.IOUtils;
    027import org.apache.commons.io.build.AbstractOrigin;
    028import org.apache.commons.io.build.AbstractOrigin.ByteArrayOrigin;
    029import org.apache.commons.io.build.AbstractOrigin.FileOrigin;
    030import org.apache.commons.io.build.AbstractOrigin.PathOrigin;
    031
    032public class ByteSource {
    033
    034    public static ByteSource array(final byte[] array) {
    035        return new ByteSource(new ByteArrayOrigin(array), null);
    036    }
    037
    038    public static ByteSource array(final byte[] array, final String name) {
    039        return new ByteSource(new ByteArrayOrigin(array), name);
    040    }
    041
    042    public static ByteSource file(final File file) {
    043        return new ByteSource(new FileOrigin(file), file.getName());
    044    }
    045
    046    public static final InputStream getInputStream(final ByteSource byteSource, final long skip) throws IOException {
    047        InputStream is = null;
    048        boolean succeeded = false;
    049        try {
    050            is = byteSource.getInputStream();
    051            BinaryFunctions.skipBytes(is, skip);
    052            succeeded = true;
    053        } finally {
    054            if (!succeeded) {
    055                IOUtils.close(is);
    056            }
    057        }
    058        return is;
    059    }
    060
    061    public static ByteSource inputStream(final InputStream is, final String name) throws IOException {
    062        return new InputStreamByteSource(is, name);
    063    }
    064
    065    public static ByteSource path(final Path file) {
    066        return new ByteSource(new PathOrigin(file), Objects.toString(file.getFileName(), null));
    067    }
    068
    069    private final String fileName;
    070    private final AbstractOrigin<?, ?> origin;
    071
    072    ByteSource(final AbstractOrigin<?, ?> origin, final String fileName) {
    073        this.origin = Objects.requireNonNull(origin, "origin");
    074        this.fileName = fileName; // may be null
    075    }
    076
    077    public byte[] getByteArray(final long position, final int length) throws IOException {
    078        return origin.getByteArray(position, length);
    079    }
    080
    081    public final String getFileName() {
    082        return fileName;
    083    }
    084
    085    public InputStream getInputStream() throws IOException {
    086        return origin.getInputStream();
    087    }
    088
    089    /**
    090     * This operation can be VERY expensive; for InputStream byte sources, the entire stream must be drained to determine its length.
    091     *
    092     * @return the byte source length
    093     * @throws IOException if it fails to read the byte source data
    094     */
    095    public long size() throws IOException {
    096        return origin.size();
    097    }
    098
    099    @Override
    100    public String toString() {
    101        return getClass().getSimpleName() + "[" + getFileName() + "]";
    102    }
    103
    104}