com.github.stephenc.javaisotools.loopfs.iso9660.EntryInputStream Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of loop-fs-iso-impl Show documentation
The newest version!
/*
 * Copyright (c) 2010. Stephen Connolly.
 * Copyright (c) 2006-2007. loopy project (http://loopy.sourceforge.net).
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package com.github.stephenc.javaisotools.loopfs.iso9660;

import java.io.IOException;
import java.io.InputStream;

/**
 * InputStream that reads a FileEntry's data.
 */
class EntryInputStream extends InputStream {
    // entry within the file system
    private Iso9660FileEntry entry;

    // the parent file system
    private Iso9660FileSystem fileSystem;

    // current position within entry data
    private long pos;

    // number of remaining bytes within entry
    private long rem;

    EntryInputStream(final Iso9660FileEntry entry, final Iso9660FileSystem fileSystem) {
        this.fileSystem = fileSystem;
        this.entry = entry;
        this.pos = 0;
        this.rem = entry.getSize();
    }

    public int read(final byte b[], final int off, final int len) throws IOException {
        ensureOpen();

        if (this.rem <= 0) {
            return -1;
        }
        if (len <= 0) {
            return 0;
        }

        int toRead = len;

        if (toRead > this.rem) {
            // down cast is safe as toRead is int and greater than this.rem
            toRead = (int)this.rem;
        }

        int read;

        synchronized (this.fileSystem) {
            if (this.fileSystem.isClosed()) {
                throw new IOException("ISO file closed.");
            }

            read = this.fileSystem.readBytes(this.entry, this.pos, b, off, toRead);
        }

        if (read > 0) {
            this.pos += read;
            this.rem -= read;
        }

        return read;
    }

    public int read() throws IOException {
        ensureOpen();

        final byte[] b = new byte[1];

        if (read(b, 0, 1) == 1) {
            return b[0] & 0xff;
        } else {
            return -1;
        }
    }

    public long skip(final long n) {
        ensureOpen();

        final long len = (n > this.rem) ? this.rem : n;

        this.pos += len;
        this.rem -= len;

        if (this.rem <= 0) {
            close();
        }

        return len;
    }

    public int available() {
        if (this.rem > Integer.MAX_VALUE) {
            return Integer.MAX_VALUE;
        } else if (this.rem < 0) {
            return 0;
        } else {
            return (int) this.rem;
        }
    }

    public long size() {
        ensureOpen();

        return this.entry.getSize();
    }

    public void close() {
        this.rem = 0;
        this.entry = null;
        this.fileSystem = null;
    }

    private void ensureOpen() {
        if (null == this.entry) {
            throw new IllegalStateException("stream has been closed");
        }
    }
}