org.armedbear.lisp.URLStream Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of abcl Show documentation
Common Lisp implementation running on the JVM
There is a newer version: 1.0.1
/*
 * URLStream.java
 *
 * Copyright (C) 2010 Mark Evenson
 * $Id: URLStream.java 13440 2011-08-05 21:25:10Z ehuelsmann $
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obligated to do so.  If you do not wish to do so, delete this
 * exception statement from your version.
 */

package org.armedbear.lisp;

import static org.armedbear.lisp.Lisp.*;

import java.io.File;
import java.io.InputStream;
import java.io.Reader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.BufferedReader;

/** 
 * Stream interface for a URL.
 * 
 * This only supports reading from the stream.
 */
public final class URLStream extends Stream
{
    private final Pathname pathname;
    private final InputStream input;
    private final Reader reader;
    private final int bytesPerUnit;

    public URLStream(Pathname pathname, String namestring,
                     LispObject elementType, LispObject direction,
                     LispObject ifExists, LispObject format)
        throws IOException
    {
        super(Symbol.URL_STREAM);
        Debug.assertTrue(direction == Keyword.INPUT);
        isInputStream = true;

        super.setExternalFormat(format);
        
        this.pathname = pathname;
        this.elementType = elementType;

        this.input = pathname.getInputStream();
        if (elementType == Symbol.CHARACTER || elementType == Symbol.BASE_CHAR) {
            isCharacterStream = true;
            bytesPerUnit = 1;
            InputStreamReader isr = new InputStreamReader(input);
            this.reader = (Reader) new BufferedReader(isr);
            initAsCharacterInputStream(this.reader);
        } else {
            isBinaryStream = true;
            int width = Fixnum.getValue(elementType.cadr());
            bytesPerUnit = width / 8;
            this.reader = null;
            initAsBinaryInputStream(this.input);
        }
    }

    @Override
    public LispObject typeOf()
    {
        return Symbol.URL_STREAM;
    }

    @Override
    public LispObject classOf()
    {
        return BuiltInClass.URL_STREAM;
    }

    @Override
    public LispObject typep(LispObject typeSpecifier)
    {
        if (typeSpecifier == Symbol.URL_STREAM)
            return T;
        if (typeSpecifier == BuiltInClass.URL_STREAM)
            return T;
        return super.typep(typeSpecifier);
    }

    @Override
    public void setExternalFormat(LispObject format) {
        super.setExternalFormat(format);
    }

    public Pathname getPathname()
    {
        return pathname;
    }

    @Override
    public void _close()
    {
        try {
            if (input != null) {
                input.close();
            }
            if (reader != null) {
                reader.close();
            }
            setOpen(false);
        }
        catch (IOException e) {
            error(new StreamError(this, e));
        }
    }

    @Override
    public String printObject()
    {
        StringBuffer sb = new StringBuffer();
        sb.append(Symbol.URL_STREAM.printObject());
        String namestring = pathname.getNamestring();
        if (namestring != null) {
            sb.append(" ");
            sb.append(namestring);
        }
        return unreadableString(sb.toString());
    }
}