/*

 * Floating point AAN IDCT

 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "faanidct.h"

#include "libavutil/common.h"

#include "libavutil/emms.h"

/* To allow switching to double. */

typedef float FLOAT;

#define B0 1.0000000000000000000000

#define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)

#define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)

#define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)

#define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)

#define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)

#define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)

#define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)

#define A4 0.70710678118654752438 // cos(pi*4/16)

#define A2 0.92387953251128675613 // cos(pi*2/16)

static const FLOAT prescale[64]={

B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,

B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,

B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,

B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,

B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,

B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,

B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,

B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,

};

static inline void p8idct(int16_t data[64], FLOAT temp[64], uint8_t *dest,

                          ptrdiff_t stride, int x, int y, int type)

{

    int i;

    FLOAT s04, d04, s17, d17, s26, d26, s53, d53;

    FLOAT os07, os16, os25, os34;

    FLOAT od07, od16, od25, od34;

    for(i=0; i<y*8; i+=y){

        s17= temp[1*x + i] + temp[7*x + i];

        d17= temp[1*x + i] - temp[7*x + i];

        s53= temp[5*x + i] + temp[3*x + i];

        d53= temp[5*x + i] - temp[3*x + i];

        od07=  s17 + s53;

        od25= (s17 - s53)*(2*A4);

        od34=  d17*(2*(B6-A2)) - d53*(2*A2);

        od16=  d53*(2*(A2-B2)) + d17*(2*A2);

        od16 -= od07;

        od25 -= od16;

        od34 += od25;

        s26 = temp[2*x + i] + temp[6*x + i];

        d26 = temp[2*x + i] - temp[6*x + i];

        d26*= 2*A4;

        d26-= s26;

        s04= temp[0*x + i] + temp[4*x + i];

        d04= temp[0*x + i] - temp[4*x + i];

        os07= s04 + s26;

        os34= s04 - s26;

        os16= d04 + d26;

        os25= d04 - d26;

        if(type==0){

            temp[0*x + i]= os07 + od07;

            temp[7*x + i]= os07 - od07;

            temp[1*x + i]= os16 + od16;

            temp[6*x + i]= os16 - od16;

            temp[2*x + i]= os25 + od25;

            temp[5*x + i]= os25 - od25;

            temp[3*x + i]= os34 - od34;

            temp[4*x + i]= os34 + od34;

        }else if(type==1){

            data[0*x + i]= lrintf(os07 + od07);

            data[7*x + i]= lrintf(os07 - od07);

            data[1*x + i]= lrintf(os16 + od16);

            data[6*x + i]= lrintf(os16 - od16);

            data[2*x + i]= lrintf(os25 + od25);

            data[5*x + i]= lrintf(os25 - od25);

            data[3*x + i]= lrintf(os34 - od34);

            data[4*x + i]= lrintf(os34 + od34);

        }else if(type==2){

            dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));

            dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));

            dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));

            dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));

            dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));

            dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));

            dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));

            dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));

        }else{

            dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));

            dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));

            dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));

            dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));

            dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));

            dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));

            dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));

            dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));

        }

    }

}

void ff_faanidct(int16_t block[64]){

    FLOAT temp[64];

    int i;

    emms_c();

    for(i=0; i<64; i++)

        temp[i] = block[i] * prescale[i];

    p8idct(block, temp, NULL, 0, 1, 8, 0);

    p8idct(block, temp, NULL, 0, 8, 1, 1);

}

void ff_faanidct_add(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])

{

    FLOAT temp[64];

    int i;

    emms_c();

    for(i=0; i<64; i++)

        temp[i] = block[i] * prescale[i];

    p8idct(block, temp, NULL,         0, 1, 8, 0);

    p8idct(NULL , temp, dest, line_size, 8, 1, 2);

}

void ff_faanidct_put(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])

{

    FLOAT temp[64];

    int i;

    emms_c();

    for(i=0; i<64; i++)

        temp[i] = block[i] * prescale[i];

    p8idct(block, temp, NULL,         0, 1, 8, 0);

    p8idct(NULL , temp, dest, line_size, 8, 1, 3);

}