/* 

 * 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.c,v 1.31 2017/08/23 13:22:23 robert Exp $ */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <assert.h>

#include "common.h"

#include "decode_i386.h"

#ifdef WITH_DMALLOC

#include <dmalloc.h>

#endif

#include "layer1.h"

static int gd_are_hip_tables_layer1_initialized = 0;

void

hip_init_tables_layer1(void)

{

    if (gd_are_hip_tables_layer1_initialized) {

        return;

    }

    gd_are_hip_tables_layer1_initialized = 1;

}

typedef struct sideinfo_layer_I_struct

{

    unsigned char allocation[SBLIMIT][2]; 

    unsigned char scalefactor[SBLIMIT][2];

} sideinfo_layer_I;

static int

I_step_one(PMPSTR mp, sideinfo_layer_I* si)

{

    struct frame *fr = &(mp->fr);

    int     jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32;

    int     i;

    int     illegal_value_detected = 0;

    unsigned char const ba15 = 15; /* bit pattern not allowed, looks like sync(?) */

    memset(si, 0, sizeof(*si));

    assert(fr->stereo == 1 || fr->stereo == 2);

    if (fr->stereo == 2) {

        for (i = 0; i < jsbound; i++) {

            unsigned char b0 = get_leq_8_bits(mp, 4);       /* values 0-15 */

            unsigned char b1 = get_leq_8_bits(mp, 4);       /* values 0-15 */

            si->allocation[i][0] = b0;

            si->allocation[i][1] = b1;

            if (b0 == ba15 || b1 == ba15)

                illegal_value_detected = 1;

        }

        for (i = jsbound; i < SBLIMIT; i++) {

            unsigned char b = get_leq_8_bits(mp, 4);        /* values 0-15 */

            si->allocation[i][0] = b;

            si->allocation[i][1] = b;

            if (b == ba15)

                illegal_value_detected =  1;

        }

        for (i = 0; i < SBLIMIT; i++) {

            unsigned char n0 = si->allocation[i][0];

            unsigned char n1 = si->allocation[i][1];

            unsigned char b0 = n0 ? get_leq_8_bits(mp, 6) : 0;  /* values 0-63 */

            unsigned char b1 = n1 ? get_leq_8_bits(mp, 6) : 0;  /* values 0-63 */

            si->scalefactor[i][0] = b0;

            si->scalefactor[i][1] = b1;

        }

    }

    else {

        for (i = 0; i < SBLIMIT; i++) {

            unsigned char b0 =  get_leq_8_bits(mp, 4);          /* values 0-15 */

            si->allocation[i][0] = b0;

            if (b0 == ba15)

                illegal_value_detected = 1;

        }

        for (i = 0; i < SBLIMIT; i++) {

            unsigned char n0 = si->allocation[i][0];

            unsigned char b0 = n0 ? get_leq_8_bits(mp, 6) : 0;  /* values 0-63 */

            si->scalefactor[i][0] = b0;

        }

    }

    return illegal_value_detected;

}

static void

I_step_two(PMPSTR mp, sideinfo_layer_I *si, real fraction[2][SBLIMIT])

{

    double  r0, r1;

    struct frame *fr = &(mp->fr);

    int     ds_limit = fr->down_sample_sblimit;

    int     i;

    assert(fr->stereo == 1 || fr->stereo == 2);

    if (fr->stereo == 2) {

        int     jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32;

        for (i = 0; i < jsbound; i++) {

            unsigned char i0 = si->scalefactor[i][0];

            unsigned char i1 = si->scalefactor[i][1];

            unsigned char n0 = si->allocation[i][0];

            unsigned char n1 = si->allocation[i][1];

            assert( i0 < 64 );

            assert( i1 < 64 );

            assert( n0 < 16 );

            assert( n1 < 16 );

            if (n0 > 0) {

                unsigned short v = get_leq_16_bits(mp, n0 + 1); /* 0-65535 */

                r0 = (((-1) << n0) + v + 1) * muls[n0 + 1][i0];

            }

            else {

                r0 = 0;

            }

            if (n1 > 0) {

                unsigned short v = get_leq_16_bits(mp, n1 + 1); /* 0-65535 */

                r1 = (((-1) << n1) + v + 1) * muls[n1 + 1][i1];

            }

            else {

                r1 = 0;

            }

            fraction[0][i] = (real)r0;

            fraction[1][i] = (real)r1;

        }

        for (i = jsbound; i < SBLIMIT; i++) {

            unsigned char i0 = si->scalefactor[i][0];

            unsigned char i1 = si->scalefactor[i][1];

            unsigned char n = si->allocation[i][0];

            assert( i0 < 64 );

            assert( i1 < 64 );

            assert( n < 16 );

            if (n > 0) {

                unsigned short v = get_leq_16_bits(mp, n + 1); /* 0-65535 */

                unsigned int w = (((-1) << n) + v + 1);

                r0 = w * muls[n + 1][i0];

                r1 = w * muls[n + 1][i1];

            }

            else {

                r0 = r1 = 0;

            }

            fraction[0][i] = (real)r0;

            fraction[1][i] = (real)r1;

        }

        for (i = ds_limit; i < SBLIMIT; i++) {

            fraction[0][i] = 0.0;

            fraction[1][i] = 0.0;

        }

    }

    else {

        for (i = 0; i < SBLIMIT; i++) {

            unsigned char n = si->allocation[i][0];

            unsigned char j = si->scalefactor[i][0];

            assert( j < 64 );

            assert( n < 16 );

            if (n > 0) {

                unsigned short v = get_leq_16_bits(mp, n + 1);

                r0 = (((-1) << n) + v + 1) * muls[n + 1][j];

            }

            else {

                r0 = 0;

            }

            fraction[0][i] = (real)r0;

        }

        for (i = ds_limit; i < SBLIMIT; i++) {

            fraction[0][i] = 0.0;

        }

    }

}

int

decode_layer1_sideinfo(PMPSTR mp)

{

    (void) mp;

    /* FIXME: extract side information and check values */

    return 0;

}

int

decode_layer1_frame(PMPSTR mp, unsigned char *pcm_sample, int *pcm_point)

{

    real    fraction[2][SBLIMIT]; /* FIXME: change real -> double ? */

    sideinfo_layer_I si;

    struct frame *fr = &(mp->fr);

    int     single = fr->single;

    int     i, clip = 0;

    if (I_step_one(mp, &si)) {

        lame_report_fnc(mp->report_err, "hip: Aborting layer 1 decode, illegal bit allocation value\n");

        return -1;

    }

    if (fr->stereo == 1 || single == 3)

        single = 0;

    if (single >= 0) {

        /* decoding one of possibly two channels */

        for (i = 0; i < SCALE_BLOCK; i++) {

            I_step_two(mp, &si, fraction);

            clip += synth_1to1_mono(mp, (real *) fraction[single], pcm_sample, pcm_point);

        }

    }

    else {

        for (i = 0; i < SCALE_BLOCK; i++) {

            int     p1 = *pcm_point;

            I_step_two(mp, &si, fraction);

            clip += synth_1to1(mp, (real *) fraction[0], 0, pcm_sample, &p1;;

            clip += synth_1to1(mp, (real *) fraction[1], 1, pcm_sample, pcm_point);

        }

    }

    return clip;

}