SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package java.io;

import cc.squirreljme.runtime.cldc.annotation.Api;
import cc.squirreljme.runtime.cldc.annotation.ImplementationNote;
import cc.squirreljme.runtime.cldc.debug.Debugging;
import java.lang.ref.WeakReference;

@Api
public abstract class Reader
    implements Closeable
{
    /** The lock to use when performing read operations. */
    @Api
    @ImplementationNote("This is only used with the skip() method.")
    protected Object lock;
    
    /**
     * Initializes the base reader.
     *
     * @since 2018/10/13
     */
    @Api
    @ImplementationNote("The lock should be initialized to this, however " +
        "this would result in the reader itself never able to be freed " +
        "because it refers to itself.")
    protected Reader()
    {
        this.lock = new WeakReference<>(this);
    }
    
    /**
     * Initializes the reader to lock against the given object.
     *
     * @param __l The object to lock against.
     * @throws NullPointerException On null arguments.
     * @since 2018/10/13
     */
    @Api
    protected Reader(Object __l)
        throws NullPointerException
    {
        if (__l == null)
            throw new NullPointerException("NARG");
        
        this.lock = __l;
    }
    
    /**
     * Reads multiple characters.
     *
     * @param __c The output characters.
     * @param __o The offset into the output.
     * @param __l The number of characters to read.
     * @return The number of read characters or {@code -1} on end of file.
     * @throws IndexOutOfBoundsException If the offset and/or length are
     * negative or exceed the array bounds.
     * @throws IOException On read errors.
     * @throws NullPointerException On null arguments.
     * @since 2018/10/13
     */
    @Api
    public abstract int read(char[] __c, int __o, int __l)
        throws IndexOutOfBoundsException, IOException, NullPointerException;
    
    @Api
    public void mark(int __a)
        throws IOException
    {
        if (false)
            throw new IOException();
        throw Debugging.todo();
    }
    
    @Api
    public boolean markSupported()
    {
        throw Debugging.todo();
    }
    
    /**
     * Reads a single character from the input.
     *
     * @return The character which was read or {@code -1} on end of file.
     * @throws IOException On read errors.
     * @since 2018/10/13
     */
    @Api
    public int read()
        throws IOException
    {
        // Try reading the character in a loop
        char[] buf = new char[1];
        for (;;)
        {
            int rc = this.read(buf, 0, 1);
            
            // Try to read character again
            if (rc == 0)
                continue;
            
            // EOF
            else if (rc < 0)
                return rc;
            
            return buf[0];
        }
    }
    
    /**
     * Reads in multiple characters from the stream.
     *
     * @param __c The characters to read.
     * @return The number of read characters.
     * @throws IOException On read errors.
     * @throws NullPointerException On null arguments.
     * @since 2018/10/13
     */
    @Api
    public int read(char[] __c)
        throws IOException, NullPointerException
    {
        if (__c == null)
            throw new NullPointerException("NARG");
        
        return this.read(__c, 0, __c.length);
    }
    
    @Api
    public boolean ready()
        throws IOException
    {
        if (false)
            throw new IOException();
        throw Debugging.todo();
    }
    
    @Api
    public void reset()
        throws IOException
    {
        if (false)
            throw new IOException();
        throw Debugging.todo();
    }
    
    @Api
    public long skip(long __a)
        throws IOException
    {
        // To prevent clashes when skipping characters
        synchronized (this.__lock())
        {
            if (false)
                throw new IOException();
            throw Debugging.todo();
        }
    }
    
    /**
     * Returns the locking object.
     *
     * @return The locking object.
     * @since 2018/10/13
     */
    @Api
    final Object __lock()
    {
        Object rv = this.lock;
        return (rv == null ? this : rv);
    }
}