/* 
 * layer1.c: Mpeg Layer-1 audio decoder 
 *
 * Copyright (C) 1999-2010 The L.A.M.E. project
 *
 * Initially written by Michael Hipp, see also AUTHORS and README.
 *  
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* $Id: Layer1.java,v 1.5 2011/05/31 19:42:01 kenchis Exp $ */

package mpg;

import mpg.Decode.Factory;
import mpg.MPGLib.ProcessedBytes;
import mpg.MPGLib.mpstr_tag;

public class Layer1 {
	private Common common;
	private Decode decode;

	public void setModules(Common c, Decode d) {
		common = c;
		decode = d;
	}

	private void I_step_one(final mpstr_tag mp, final int balloc[],
			final int scale_index[], final Frame fr) {
	    int ba = 0;
	    int sca = 0;

	    assert(fr.stereo == 1 || fr.stereo == 2);
	    if (fr.stereo == 2) {
	        int     i;
	        int     jsbound = fr.jsbound;
	        for (i = 0; i < jsbound; i++) {
	        	balloc[ba++] = common.getbits(mp, 4);
	        	balloc[ba++] = common.getbits(mp, 4);
	        }
	        for (i = jsbound; i < MPG123.SBLIMIT; i++)
	        	balloc[ba++] = common.getbits(mp, 4);

	        ba = 0;

	        for (i = 0; i < jsbound; i++) {
	            if ((balloc[ba]++)!=0)
	            	scale_index[sca++] = common.getbits(mp, 6);
	            if ((balloc[ba++])!=0)
	            	scale_index[sca++] = common.getbits(mp, 6);
	        }
	        for (i = jsbound; i < MPG123.SBLIMIT; i++)
	            if ((balloc[ba++])!=0) {
	            	scale_index[sca++] = common.getbits(mp, 6);
	            	scale_index[sca++] = common.getbits(mp, 6);
	            }
	    }
	    else {
	        int     i;
	        for (i = 0; i < MPG123.SBLIMIT; i++)
	        	balloc[ba++] = common.getbits(mp, 4);
	        ba = 0;
	        for (i = 0; i < MPG123.SBLIMIT; i++)
	            if ((balloc[ba++])!=0)
	            	scale_index[sca++] = common.getbits(mp, 6);
	    }
	}

	private void I_step_two(final mpstr_tag mp, final float fraction[][],
			final int balloc[], final int scale_index[], final Frame fr) {
	    int     i, n;
	    int     smpb[]=new int[2 * MPG123.SBLIMIT]; /* values: 0-65535 */
	    int    sample;
	    int ba = 0;
	    int sca = 0;

	    assert(fr.stereo == 1 || fr.stereo == 2);
	    if (fr.stereo == 2) {
	        int     jsbound = fr.jsbound;
	        int f0 = 0;
	        int f1 = 0;
	        ba = 0;
	        for (sample = 0, i = 0; i < jsbound; i++) {
	            n = balloc[ba++];
	            if (n!=0)
	                smpb[sample++] = common.getbits(mp, n + 1);
	            n = balloc[ba++];
	            if (n!=0)
	                smpb[sample++] = common.getbits(mp, n + 1);
	        }
	        for (i = jsbound; i < MPG123.SBLIMIT; i++) {
	            n = balloc[ba++];
	            if (n!=0)
	                smpb[sample++] = common.getbits(mp, n + 1);
	        }
	        ba = 0;
	        for (sample = 0, i = 0; i < jsbound; i++) {
	            n = balloc[ba++];
	            if (n!=0)
	            	fraction[0][f0++] = (float) (((-1) << n) + (smpb[sample++]) + 1) * common.muls[n + 1][scale_index[sca++]];
	            else
	            	fraction[0][f0++] = 0.0f;
	            n = balloc[ba++];
	            if (n!=0)
	            	fraction[1][f1++] = (float) (((-1) << n) + (smpb[sample++]) + 1) * common.muls[n + 1][scale_index[sca++]];
	            else
	            	fraction[1][f1++] = 0.0f;
	        }
	        for (i = jsbound; i < MPG123.SBLIMIT; i++) {
	            n = balloc[ba++];
	            if (n!=0) {
	                float    samp = (float) (((-1) << n) + (smpb[sample++]) + 1);
	                fraction[0][f0++] = samp * common.muls[n + 1][scale_index[sca++]];
	                fraction[1][f1++] = samp * common.muls[n + 1][scale_index[sca++]];
	            }
	            else
	            	fraction[0][f0++] = fraction[1][f1++] = 0.0f;
	        }
	        for (i = fr.down_sample_sblimit; i < 32; i++)
	            fraction[0][i] = fraction[1][i] = 0.0f;
	    }
	    else {
	        int f0 = 0;
	        ba = 0;
	        for (sample = 0, i = 0; i < MPG123.SBLIMIT; i++) {
	            n = balloc[ba++];
	            if (n!=0)
	                smpb[sample++] = common.getbits(mp, n + 1);
	        }
	        ba = 0;
	        for (sample = 0, i = 0; i < MPG123.SBLIMIT; i++) {
	            n = balloc[ba++];
	            if (n!=0)
	            	fraction[0][f0++] = (float) (((-1) << n) + (smpb[sample++]) + 1) * common.muls[n + 1][scale_index[sca++]];
	            else
	            	fraction[0][f0++] = 0.0f;
	        }
	        for (i = fr.down_sample_sblimit; i < 32; i++)
	            fraction[0][i] = 0.0f;
	    }
	}

	public <T> int do_layer1(final mpstr_tag mp, final T[] pcm_sample,
			final ProcessedBytes pcm_point, final Factory<T> tFactory) {
	    int     clip = 0;
	    int balloc[]=new int[2 * MPG123.SBLIMIT];
	    int scale_index[]=new int[2 * MPG123.SBLIMIT];
	    float    fraction[][]=new float[2][MPG123.SBLIMIT];
	    Frame fr = mp.fr;
	    int     i, stereo = fr.stereo;
	    int     single = fr.single;

	    fr.jsbound = (fr.mode == MPG123.MPG_MD_JOINT_STEREO) ? (fr.mode_ext << 2) + 4 : 32;

	    if (stereo == 1 || single == 3)
	        single = 0;

	    I_step_one(mp, balloc, scale_index, fr);

	    for (i = 0; i < MPG123.SCALE_BLOCK; i++) {
	        I_step_two(mp, fraction, balloc, scale_index, fr);

	        if (single >= 0) {
	            clip += decode.synth_1to1_mono(mp, fraction[single], 0, pcm_sample, pcm_point, tFactory);
	        }
	        else {
            	ProcessedBytes p1 = new ProcessedBytes();
            	p1.pb = pcm_point.pb;
	            clip += decode.synth_1to1(mp, fraction[0], 0, 0, pcm_sample, p1, tFactory);
	            clip += decode.synth_1to1(mp, fraction[1], 0, 1, pcm_sample, pcm_point, tFactory);
	        }
	    }

	    return clip;
	}
}