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 cc.squirreljme.jvm.pack.mem;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import java.io.DataOutput;
import java.io.EOFException;
import java.io.IOException;
import java.io.OutputStream;

/**
 * This is an output stream which can directly write to memory areas.
 * 
 * For anything from {@link DataOutput} the proper type based methods are used,
 * as such if there is a specific byte order that is used it will be
 * derived from this.
 *
 * @since 2019/06/14
 */
public final class WritableMemoryOutputStream
    extends OutputStream
    implements DataOutput, MemoryStream
{
    /** The base write address. */
    protected final long address;
    
    /** The number of bytes that can be written. */
    protected final long length;
    
    /** The output memory. */
    protected final WritableMemory memory;
    
    /** The current write offset. */
    private int _at;
    
    /**
     * Initializes the stream, the byte order is big endian.
     *
     * @param __mem The memory.
     * @throws NullPointerException On null arguments.
     * @since 2020/02/09
     */
    public WritableMemoryOutputStream(WritableMemory __mem)
        throws NullPointerException
    {
        this(__mem, 0, __mem.memRegionSize());
    }
    
    /**
     * Initializes the stream, the byte order is big endian.
     *
     * @param __mem The memory.
     * @param __addr The start address.
     * @param __len The length.
     * @throws IllegalArgumentException If the length is negative.
     * @throws NullPointerException On null arguments.
     * @since 2019/06/14
     */
    public WritableMemoryOutputStream(WritableMemory __mem,
        long __addr, long __len)
        throws IllegalArgumentException, NullPointerException
    {
        if (__mem == null)
            throw new NullPointerException("NARG");
        if (__len < 0)
            throw new IllegalArgumentException("NEGV");
        
        this.memory = __mem;
        this.address = __addr;
        this.length = __len;
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/04
     * @return
     */
    @Override
    public long address()
    {
        return this.address + this._at;
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/04
     */
    @Override
    public int offset()
    {
        return this._at;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/06/14
     */
    @Override
    public final void close()
    {
        // Does nothing
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/06/14
     */
    @Override
    public final void flush()
    {
        // Does nothing
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/06/14
     */
    @Override
    public final void write(int __b)
        throws IOException
    {
        // Check for end of memory
        int at = this._at;
        this.__check(1);
        
        // Write
        this.memory.memWriteByte(this.address + at, __b);
        this._at = at + 1;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/06/14
     */
    @Override
    public final void write(byte[] __b)
        throws IOException, NullPointerException
    {
        this.write(__b, 0, __b.length);
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/06/14
     */
    @Override
    public final void write(byte[] __b, int __o, int __l)
        throws IOException, NullPointerException
    {
        if (__b == null)
            throw new NullPointerException("NARG");
        if (__o < 0 || __l < 0 || (__o + __l) > __b.length)
            throw new IndexOutOfBoundsException("IOOB");
        
        // Check for end of memory
        int at = this._at;
        this.__check(1);
        
        // Do not write past the bounds
        long left = this.length - at;
        if (__l > left)
            __l = (int)left;
        
        // Write to memory
        this.memory.memWriteBytes(this.address + at, __b, __o, __l);
        
        // Increase pointer
        this._at = at + __l;
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeBoolean(boolean __v)
        throws IOException
    {
        this.writeByte((__v ? 1 : 0));
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeByte(int __v)
        throws IOException
    {
        this.memory.memWriteByte(this.__check(1), __v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeBytes(String __v)
        throws IOException
    {
        throw Debugging.todo();
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeChar(int __v)
        throws IOException
    {
        this.writeShort((short)__v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeChars(String __v)
        throws IOException
    {
        throw Debugging.todo();
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeDouble(double __v)
        throws IOException
    {
        this.writeLong(Double.doubleToRawLongBits(__v));
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeFloat(float __v)
        throws IOException
    {
        this.writeInt(Float.floatToRawIntBits(__v));
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeInt(int __v)
        throws IOException
    {
        this.memory.memWriteInt(this.__check(4), __v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeLong(long __v)
        throws IOException
    {
        this.memory.memWriteLong(this.__check(8), __v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeShort(int __v)
        throws IOException
    {
        this.memory.memWriteShort(this.__check(2), __v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/02/09
     */
    @Override
    public void writeUTF(String __v)
        throws IOException
    {
        throw Debugging.todo();
    }
    
    /**
     * Checks for a write which would overflow.
     * 
     * @param __len The number of bytes to check on write.
     * @return The address to read from.
     * @throws IllegalArgumentException If the length is zero or negative.
     * @throws EOFException If the end of file is reached.
     * @since 2021/02/14
     */
    private long __check(int __len)
        throws IllegalArgumentException, EOFException
    {
        if (__len <= 0)
            throw new IllegalArgumentException("INEG");
        
        /* {@squirreljme.error ZZ41 Reached end of memory stream.
        (The position; The length of the stream; The length checked)} */
        int at = this._at;
        if (at + (__len - 1) > this.length)
            throw new EOFException(String.format("ZZ41 %d %d %d",
                at, this.length, __len));
        
        return this.address + at;
    }
}