/*
 * MDCT/IMDCT transforms
 * Copyright (c) 2002 Fabrice Bellard.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "dsputil.h"

/**
 * @file mdct.c
 * MDCT/IMDCT transforms.
 */

/**
 * init MDCT or IMDCT computation.
 */
int ff_mdct_init(MDCTContext *s, int nbits, int inverse)
{
    int n, n4, i;
    float alpha;

    memset(s, 0, sizeof(*s));
    n = 1 << nbits;
    s->nbits = nbits;
    s->n = n;
    n4 = n >> 2;
    s->tcos = av_malloc(n4 * sizeof(int));
    if (!s->tcos)
        goto fail;
    s->tsin = av_malloc(n4 * sizeof(int));
    if (!s->tsin)
        goto fail;

    for(i=0;i<n4;i++)
	{
		float sin_tmp, cos_tmp;
		alpha = 2 * M_PI * (i + 1.0 / 8.0) / n;

		sin_tmp = -sin(alpha);
		cos_tmp = -cos(alpha);

        s->tcos[i] = -float2fp(cos_tmp);
        s->tsin[i] = -float2fp(sin_tmp);
    }
    if (ff_fft_init(&s->fft, s->nbits - 2, inverse) < 0)
        goto fail;
    return 0;
 fail:
    av_freep(&s->tcos);
    av_freep(&s->tsin);
    return -1;
}

/* complex multiplication: p = a * b */
#define CMUL(pre, pim, are, aim, bre, bim) \
{\
    float _are = (are);\
    float _aim = (aim);\
    float _bre = (bre);\
    float _bim = (bim);\
    (pre) = _are * _bre - _aim * _bim;\
    (pim) = _are * _bim + _aim * _bre;\
}


#define CMULCOPY(pre, pim, are, aim, bre, bim) \
{\
	long long _are = (are);\
	long long _aim = (aim);\
	long long _bre = (bre);\
	long long _bim = (bim);\
	(pre) = (fpMul(_are, _bre)) - (fpMul(_aim , _bim));\
	(pim) = (fpMul(_are , _bim)) + (fpMul(_aim , _bre));\
}

#define  fpMulCopy(x, y) \
	(( x / 0x0000000000010000) * (y))


#define CMULHD(pre, pim, are, aim, bre, bim) \
{\
	long long _are = (are);\
	long long _aim = (aim);\
	long long _bre = (bre);\
	long long _bim = (bim);\
	(pre) = (fpMulCopy(_are, _bre)) - (fpMulCopy(_aim , _bim));\
	(pim) = (fpMulCopy(_are , _bim)) + (fpMulCopy(_aim , _bre));\
}
/**
 * Compute inverse MDCT of size N = 2^nbits
 * @param output N samples
 * @param input N/2 samples
 * @param tmp N/2 samples
 */
void ff_imdct_calc(MDCTContext *s, FFTSample *output,
                   const FFTSample *input, FFTSample *tmp)
{
    int k, n8, n4, n2, n, j;
    const uint16_t *revtab = s->fft.revtab;
    const int *tcos = s->tcos;
    const int *tsin = s->tsin;
    const int *in1, *in2;

	MYFFTComplex32* z = (MYFFTComplex32*) tmp;

	long long* output_copy = (long long*) output;

    n = 1 << s->nbits;
    n2 = n >> 1;
    n4 = n >> 2;
    n8 = n >> 3;

    /* pre rotation */
    in1 = (int*) input;
    in2 = in1 + n2 - 1;

    for(k = 0; k < n4; k++)
	{
		j=revtab[k];

		// 64 BIT
		z[j].re = ( (long long)(*in2 ) * (long long)tcos[k] ) - ( (long long)(*in1) * (long long)tsin[k] );
		z[j].im = ( (long long)(*in2) * (long long)tsin[k] ) + ( (long long)(*in1) * (long long)tcos[k] );


        in1 += 2;
        in2 -= 2;
    }

    ff_fft_calc(&s->fft, (FFTComplex *)z);

    for(k = 0; k < n4; k++)
	{
	    CMULHD(z[k].re, z[k].im, z[k].re, z[k].im, tcos[k], tsin[k]);
    }

    for(k = 0; k < n8; k++) {
        output_copy[2*k] = -(z[n8 + k].im);
        output_copy[n2-1-2*k] = (z[n8 + k].im);

        output_copy[2*k+1] = (z[n8-1-k].re);
        output_copy[n2-1-2*k-1] = -(z[n8-1-k].re);

        output_copy[n2 + 2*k] = -(z[k+n8].re);
        output_copy[n-1- 2*k] = -(z[k+n8].re);

        output_copy[n2 + 2*k+1] = (z[n8-k-1].im);
        output_copy[n-2 - 2 * k] = (z[n8-k-1].im);
    }
}

/**
 * Compute MDCT of size N = 2^nbits
 * @param input N samples
 * @param out N/2 samples
 * @param tmp temporary storage of N/2 samples
 */
void ff_mdct_calc(MDCTContext *s, FFTSample *out,
                  const FFTSample *input, FFTSample *tmp)
{
    int i, j, n, n8, n4, n2, n3;
    FFTSample re, im, re1, im1;
    const uint16_t *revtab = s->fft.revtab;
    const FFTSample *tcos = (const FFTSample *)s->tcos;
    const FFTSample *tsin = (const FFTSample *)s->tsin;
    FFTComplex *x = (FFTComplex *)tmp;

    n = 1 << s->nbits;
    n2 = n >> 1;
    n4 = n >> 2;
    n8 = n >> 3;
    n3 = 3 * n4;

    /* pre rotation */
    for(i=0;i<n8;i++) {
        re = -input[2*i+3*n4] - input[n3-1-2*i];
        im = -input[n4+2*i] + input[n4-1-2*i];
        j = revtab[i];
        CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);

        re = input[2*i] - input[n2-1-2*i];
        im = -(input[n2+2*i] + input[n-1-2*i]);
        j = revtab[n8 + i];
        CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
    }

    ff_fft_calc(&s->fft, x);

    /* post rotation */
    for(i=0;i<n4;i++) {
        re = x[i].re;
        im = x[i].im;
        CMUL(re1, im1, re, im, -tsin[i], -tcos[i]);
        out[2*i] = im1;
        out[n2-1-2*i] = re1;
    }
}

void ff_mdct_end(MDCTContext *s)
{
    av_freep(&s->tcos);
    av_freep(&s->tsin);
    ff_fft_end(&s->fft);
}