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.vm;

import cc.squirreljme.runtime.cldc.util.StreamUtils;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import net.multiphasicapps.zip.streamreader.ZipStreamEntry;
import net.multiphasicapps.zip.streamreader.ZipStreamReader;

/**
 * This represents a class library which has been read into memory.
 *
 * @since 2018/12/08
 */
public final class InMemoryClassLibrary
    implements VMClassLibrary
{
    /** The name of this library. */
    protected final String name;
    
    /** The cache. */
    private final Map<String, byte[]> _cache;
    
    /**
     * Initializes the library.
     *
     * @param __n The name.
     * @param __m The internal mapping, the byte arrays will not be copied.
     * @throws NullPointerException On null arguments.
     * @since 2018/12/08
     */
    public InMemoryClassLibrary(String __n, Map<String, byte[]> __m)
        throws NullPointerException
    {
        if (__n == null || __m == null)
            throw new NullPointerException("NARG");
        
        this.name = __n;
        this._cache = __m;
    }
    
    /**
     * {@inheritDoc}
     * @since 2019/04/21
     */
    @Override
    public final String[] listResources()
    {
        Collection<String> names = this._cache.keySet();
        return names.<String>toArray(new String[names.size()]);
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/08
     */
    @Override
    public final String name()
    {
        return this.name;
    }
    
    /**
     * {@inheritDoc}
     * @since 2021/06/13
     */
    @Override
    public Path path()
    {
        return null;
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/08
     */
    @Override
    public final InputStream resourceAsStream(String __rc)
        throws IOException, NullPointerException
    {
        if (__rc == null)
            throw new NullPointerException("NARG");
        
        // See if the byte data exists
        byte[] rv = this._cache.get(__rc);
        if (rv == null)
            return null;
        
        // Then use a byte array on it
        return new ByteArrayInputStream(rv);
    }
    
    /**
     * Loads ZIP file data.
     *
     * @param __n The library name.
     * @param __in The input stream.
     * @return The class library.
     * @throws IOException On read errors.
     * @throws NullPointerException On null arguments.
     * @since 2018/12/08
     */
    @SuppressWarnings("resource")
    public static final InMemoryClassLibrary loadZip(String __n,
        ZipStreamReader __in)
        throws IOException, NullPointerException
    {
        if (__n == null || __in == null)
            throw new NullPointerException("NARG");
        
        // Target map
        Map<String, byte[]> rv = new HashMap<>();
        
        // Temporary buffer to reading class data
        byte[] buf = new byte[4096];
        
        // Process all entries
        ZipStreamEntry zse;
        while (true)
        {
            // No more entries?
            zse = __in.nextEntry();
            if (zse == null)
                break;
            
            // Copy data over
            rv.put(zse.name(), StreamUtils.readAll(zse));
            
            // Close
            zse.close();
        }
        
        return new InMemoryClassLibrary(__n, rv);
    }
}