de.intarsys.pdf.encoding.MappedReader Maven / Gradle / Ivy

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/*
 * Copyright (c) 2007, intarsys consulting GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * - Neither the name of intarsys nor the names of its contributors may be used
 *   to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package de.intarsys.pdf.encoding;

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

/**
 * A reader that uses a PDF style encoding to map byte code to unicode.
 */
public class MappedReader extends Reader {
    /**
     * the encoding we use to decode/encode the byte stream
     */
    private Encoding encoding;

    /**
     * the stream we read from
     */
    private InputStream inStream;

    /**
     * Create a MappedReader
     *
     * @param is       The underlying byte stream.
     * @param encoding The encoding to use.
     */
    public MappedReader(InputStream is, Encoding encoding) {
        super(is);
        setInStream(is);
        setEncoding(encoding);
    }

    /**
     * @see java.io.Reader#close()
     */
    @Override
    public void close() throws IOException {
        synchronized (lock) {
            if (inStream == null) {
                return;
            }
            inStream.close();
            inStream = null;
        }
    }

    /**
     * Check to make sure that the stream has not been closed
     *
     * @throws IOException if the inStream is null.
     */
    protected void ensureOpen() throws IOException {
        if (inStream == null) {
            throw new IOException("Stream closed");
        }
    }

    /**
     * The encoding used by this reader.
     *
     * @return The encoding used by this reader.
     */
    public Encoding getEncoding() {
        return encoding;
    }

    /**
     * Read characters into a portion of an array. This method will block until
     * some input is available, an I/O error occurs, or the end of the stream is
     * reached.
     *
     * @param cbuf Destination buffer
     * @param off  Offset at which to start storing characters
     * @param len  Maximum number of characters to read
     * @return The number of characters read, or -1 if the end of the stream has
     * been reached
     * @throws IOException               If an I/O error occurs
     * @throws IndexOutOfBoundsException
     */
    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
        synchronized (lock) {
            ensureOpen();
            if ((off < 0) || (off > cbuf.length) || (len < 0) || ((off + len) > cbuf.length) || ((off + len) < 0)) {
                throw new IndexOutOfBoundsException();
            }
            if (len == 0) {
                return 0;
            }

            int stop = off + len;
            int c = 0;
            for (int i = off; i < stop; i++) {
                c = encoding.getNextDecoded(inStream);
                if (c == -1) {
                    if (i == off) {
                        return -1;
                    }
                    return i - off;
                }
                cbuf[i] = (char) c;
            }
            return len;
        }
    }

    /**
     * Set the encoding to be used by this reader.
     *
     * @param encoding The new encoding to use.
     */
    private void setEncoding(Encoding encoding) {
        this.encoding = encoding;
    }

    protected void setInStream(java.io.InputStream newInStream) {
        inStream = newInStream;
    }
}