/*

  * Xvid MPEG-4 IDCT
  *
  * Copyright (C) 2006-2011 Xvid Solutions GmbH
  *

  * 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
  */
 

 /**
  * @file
  * Walken IDCT
  * Alternative IDCT implementation for decoding compatibility.
  *
  * @author Skal
  * @note This C version is not the original IDCT, but a modified one that
  *       yields the same error profile as the MMX/MMXEXT/SSE2 versions.
  */
 

 #include "config.h"
 #include "libavutil/attributes.h"
 #include "avcodec.h"
 #include "idctdsp.h"
 #include "xvididct.h"
 

 #define ROW_SHIFT 11
 #define COL_SHIFT  6
 
 // #define FIX(x)   (int)((x) * (1 << ROW_SHIFT))
 #define RND0 65536 // 1 << (COL_SHIFT + ROW_SHIFT - 1);
 #define RND1 3597  // FIX (1.75683487303);
 #define RND2 2260  // FIX (1.10355339059);
 #define RND3 1203  // FIX (0.587788325588);
 #define RND4 0
 #define RND5 120   // FIX (0.058658283817);
 #define RND6 512   // FIX (0.25);
 #define RND7 512   // FIX (0.25);
 
 static const int TAB04[] = { 22725, 21407, 19266, 16384, 12873,  8867, 4520 };
 static const int TAB17[] = { 31521, 29692, 26722, 22725, 17855, 12299, 6270 };
 static const int TAB26[] = { 29692, 27969, 25172, 21407, 16819, 11585, 5906 };
 static const int TAB35[] = { 26722, 25172, 22654, 19266, 15137, 10426, 5315 };
 
 static int idct_row(short *in, const int *const tab, int rnd)
 {
     const int c1 = tab[0];
     const int c2 = tab[1];
     const int c3 = tab[2];
     const int c4 = tab[3];
     const int c5 = tab[4];
     const int c6 = tab[5];
     const int c7 = tab[6];
 
     const int right = in[5] | in[6] | in[7];
     const int left  = in[1] | in[2] | in[3];
     if (!(right | in[4])) {
         const int k = c4 * in[0] + rnd;
         if (left) {
             const int a0 = k + c2 * in[2];
             const int a1 = k + c6 * in[2];
             const int a2 = k - c6 * in[2];
             const int a3 = k - c2 * in[2];
 
             const int b0 = c1 * in[1] + c3 * in[3];
             const int b1 = c3 * in[1] - c7 * in[3];
             const int b2 = c5 * in[1] - c1 * in[3];
             const int b3 = c7 * in[1] - c5 * in[3];
 
             in[0] = (a0 + b0) >> ROW_SHIFT;
             in[1] = (a1 + b1) >> ROW_SHIFT;
             in[2] = (a2 + b2) >> ROW_SHIFT;
             in[3] = (a3 + b3) >> ROW_SHIFT;
             in[4] = (a3 - b3) >> ROW_SHIFT;
             in[5] = (a2 - b2) >> ROW_SHIFT;
             in[6] = (a1 - b1) >> ROW_SHIFT;
             in[7] = (a0 - b0) >> ROW_SHIFT;
         } else {
             const int a0 = k >> ROW_SHIFT;
             if (a0) {
                 in[0] =
                 in[1] =
                 in[2] =
                 in[3] =
                 in[4] =
                 in[5] =
                 in[6] =
                 in[7] = a0;
             } else
                 return 0;
         }
     } else if (!(left | right)) {
         const int a0 = (rnd + c4 * (in[0] + in[4])) >> ROW_SHIFT;
         const int a1 = (rnd + c4 * (in[0] - in[4])) >> ROW_SHIFT;
 
         in[0] = a0;
         in[3] = a0;
         in[4] = a0;
         in[7] = a0;
         in[1] = a1;
         in[2] = a1;
         in[5] = a1;
         in[6] = a1;
     } else {
         const int k  = c4 * in[0] + rnd;
         const int a0 = k + c2 * in[2] + c4 * in[4] + c6 * in[6];
         const int a1 = k + c6 * in[2] - c4 * in[4] - c2 * in[6];
         const int a2 = k - c6 * in[2] - c4 * in[4] + c2 * in[6];
         const int a3 = k - c2 * in[2] + c4 * in[4] - c6 * in[6];
 
         const int b0 = c1 * in[1] + c3 * in[3] + c5 * in[5] + c7 * in[7];
         const int b1 = c3 * in[1] - c7 * in[3] - c1 * in[5] - c5 * in[7];
         const int b2 = c5 * in[1] - c1 * in[3] + c7 * in[5] + c3 * in[7];
         const int b3 = c7 * in[1] - c5 * in[3] + c3 * in[5] - c1 * in[7];
 
         in[0] = (a0 + b0) >> ROW_SHIFT;
         in[1] = (a1 + b1) >> ROW_SHIFT;
         in[2] = (a2 + b2) >> ROW_SHIFT;
         in[3] = (a3 + b3) >> ROW_SHIFT;
         in[4] = (a3 - b3) >> ROW_SHIFT;
         in[5] = (a2 - b2) >> ROW_SHIFT;
         in[6] = (a1 - b1) >> ROW_SHIFT;
         in[7] = (a0 - b0) >> ROW_SHIFT;
     }
     return 1;
 }
 
 #define TAN1  0x32EC
 #define TAN2  0x6A0A
 #define TAN3  0xAB0E
 #define SQRT2 0x5A82
 
 #define MULT(c, x, n)  (((c) * (x)) >> (n))
 // 12b version => #define MULT(c,x, n)  ((((c) >> 3) * (x)) >> ((n) - 3))
 // 12b zero-testing version:
 
 #define BUTTERFLY(a, b, tmp)     \
     (tmp) = (a) + (b);           \
     (b)   = (a) - (b);           \
     (a)   = (tmp)
 
 #define LOAD_BUTTERFLY(m1, m2, a, b, tmp, s)   \
     (m1) = (s)[(a)] + (s)[(b)];                \
     (m2) = (s)[(a)] - (s)[(b)]
 
 static void idct_col_8(short *const in)
 {
     int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;
 
     // odd
 
     mm4 = (int) in[7 * 8];
     mm5 = (int) in[5 * 8];
     mm6 = (int) in[3 * 8];
     mm7 = (int) in[1 * 8];
 
     mm0 = MULT(TAN1, mm4, 16) + mm7;
     mm1 = MULT(TAN1, mm7, 16) - mm4;
     mm2 = MULT(TAN3, mm5, 16) + mm6;
     mm3 = MULT(TAN3, mm6, 16) - mm5;
 
     mm7 = mm0 + mm2;
     mm4 = mm1 - mm3;
     mm0 = mm0 - mm2;
     mm1 = mm1 + mm3;
     mm6 = mm0 + mm1;
     mm5 = mm0 - mm1;
     mm5 = 2 * MULT(SQRT2, mm5, 16); // 2*sqrt2
     mm6 = 2 * MULT(SQRT2, mm6, 16); // Watch out: precision loss but done to match
                                     // the pmulhw used in MMX/MMXEXT/SSE2 versions
 
     // even
 
     mm1 = (int) in[2 * 8];
     mm2 = (int) in[6 * 8];
     mm3 = MULT(TAN2, mm2, 16) + mm1;
     mm2 = MULT(TAN2, mm1, 16) - mm2;
 
     LOAD_BUTTERFLY(mm0, mm1, 0 * 8, 4 * 8, spill, in);
 
     BUTTERFLY(mm0, mm3, spill);
     BUTTERFLY(mm0, mm7, spill);
     in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
     in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
     BUTTERFLY(mm3, mm4, mm0);
     in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
     in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);
 
     BUTTERFLY(mm1, mm2, mm0);
     BUTTERFLY(mm1, mm6, mm0);
     in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
     in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
     BUTTERFLY(mm2, mm5, mm0);
     in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
     in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
 }
 
 static void idct_col_4(short *const in)
 {
     int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;
 
     // odd
 
     mm0 = (int) in[1 * 8];
     mm2 = (int) in[3 * 8];
 
     mm1 = MULT(TAN1, mm0, 16);
     mm3 = MULT(TAN3, mm2, 16);
 
     mm7 = mm0 + mm2;
     mm4 = mm1 - mm3;
     mm0 = mm0 - mm2;
     mm1 = mm1 + mm3;
     mm6 = mm0 + mm1;
     mm5 = mm0 - mm1;
     mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2
     mm5 = 2 * MULT(SQRT2, mm5, 16);
 
     // even
 
     mm0 = mm1 = (int) in[0 * 8];
     mm3 = (int) in[2 * 8];
     mm2 = MULT(TAN2, mm3, 16);
 
     BUTTERFLY(mm0, mm3, spill);
     BUTTERFLY(mm0, mm7, spill);
     in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
     in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
     BUTTERFLY(mm3, mm4, mm0);
     in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
     in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);
 
     BUTTERFLY(mm1, mm2, mm0);
     BUTTERFLY(mm1, mm6, mm0);
     in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
     in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
     BUTTERFLY(mm2, mm5, mm0);
     in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
     in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
 }
 
 static void idct_col_3(short *const in)
 {
     int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill;
 
     // odd
 
     mm7 = (int) in[1 * 8];
     mm4 = MULT(TAN1, mm7, 16);
 
     mm6 = mm7 + mm4;
     mm5 = mm7 - mm4;
     mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2
     mm5 = 2 * MULT(SQRT2, mm5, 16);
 
     // even
 
     mm0 = mm1 = (int) in[0 * 8];
     mm3 = (int) in[2 * 8];
     mm2 = MULT(TAN2, mm3, 16);
 
     BUTTERFLY(mm0, mm3, spill);
     BUTTERFLY(mm0, mm7, spill);
     in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT);
     in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT);
     BUTTERFLY(mm3, mm4, mm0);
     in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT);
     in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT);
 
     BUTTERFLY(mm1, mm2, mm0);
     BUTTERFLY(mm1, mm6, mm0);
     in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT);
     in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT);
     BUTTERFLY(mm2, mm5, mm0);
     in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT);
     in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT);
 }
 
 void ff_xvid_idct(int16_t *const in)
 {
     int i, rows = 0x07;
 
     idct_row(in + 0 * 8, TAB04, RND0);
     idct_row(in + 1 * 8, TAB17, RND1);
     idct_row(in + 2 * 8, TAB26, RND2);
     if (idct_row(in + 3 * 8, TAB35, RND3))
         rows |= 0x08;
     if (idct_row(in + 4 * 8, TAB04, RND4))
         rows |= 0x10;
     if (idct_row(in + 5 * 8, TAB35, RND5))
         rows |= 0x20;
     if (idct_row(in + 6 * 8, TAB26, RND6))
         rows |= 0x40;
     if (idct_row(in + 7 * 8, TAB17, RND7))
         rows |= 0x80;
 
     if (rows & 0xF0) {
         for (i = 0; i < 8; i++)
             idct_col_8(in + i);
     } else if (rows & 0x08) {
         for (i = 0; i < 8; i++)
             idct_col_4(in + i);
     } else {
         for (i = 0; i < 8; i++)
             idct_col_3(in + i);
     }
 }
 
 static void xvid_idct_put(uint8_t *dest, int line_size, int16_t *block)

 {

     ff_xvid_idct(block);

     ff_put_pixels_clamped(block, dest, line_size);

 }
 

 static void xvid_idct_add(uint8_t *dest, int line_size, int16_t *block)

 {

     ff_xvid_idct(block);

     ff_add_pixels_clamped(block, dest, line_size);

 }
 

 av_cold void ff_xvid_idct_init(IDCTDSPContext *c, AVCodecContext *avctx)

 {
     const unsigned high_bit_depth = avctx->bits_per_raw_sample > 8;
 

     if (high_bit_depth || avctx->lowres ||

         !(avctx->idct_algo == FF_IDCT_AUTO ||

           avctx->idct_algo == FF_IDCT_XVID))

         return;
 

     if (avctx->idct_algo == FF_IDCT_XVID) {

         c->idct_put  = xvid_idct_put;
         c->idct_add  = xvid_idct_add;
         c->idct      = ff_xvid_idct;

         c->perm_type = FF_IDCT_PERM_NONE;
     }
 

     if (ARCH_X86)

         ff_xvid_idct_init_x86(c, avctx, high_bit_depth);

 
     ff_init_scantable_permutation(c->idct_permutation, c->perm_type);

 }