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      1 /*
      2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 
     12 #include <math.h>
     13 
     14 void vp8_short_fdct4x4_c(short *input, short *output, int pitch)
     15 {
     16     int i;
     17     int a1, b1, c1, d1;
     18     short *ip = input;
     19     short *op = output;
     20 
     21     for (i = 0; i < 4; i++)
     22     {
     23         a1 = ((ip[0] + ip[3])<<3);
     24         b1 = ((ip[1] + ip[2])<<3);
     25         c1 = ((ip[1] - ip[2])<<3);
     26         d1 = ((ip[0] - ip[3])<<3);
     27 
     28         op[0] = a1 + b1;
     29         op[2] = a1 - b1;
     30 
     31         op[1] = (c1 * 2217 + d1 * 5352 +  14500)>>12;
     32         op[3] = (d1 * 2217 - c1 * 5352 +   7500)>>12;
     33 
     34         ip += pitch / 2;
     35         op += 4;
     36 
     37     }
     38     ip = output;
     39     op = output;
     40     for (i = 0; i < 4; i++)
     41     {
     42         a1 = ip[0] + ip[12];
     43         b1 = ip[4] + ip[8];
     44         c1 = ip[4] - ip[8];
     45         d1 = ip[0] - ip[12];
     46 
     47         op[0]  = ( a1 + b1 + 7)>>4;
     48         op[8]  = ( a1 - b1 + 7)>>4;
     49 
     50         op[4]  =((c1 * 2217 + d1 * 5352 +  12000)>>16) + (d1!=0);
     51         op[12] = (d1 * 2217 - c1 * 5352 +  51000)>>16;
     52 
     53         ip++;
     54         op++;
     55     }
     56 }
     57 
     58 void vp8_short_fdct8x4_c(short *input, short *output, int pitch)
     59 {
     60     vp8_short_fdct4x4_c(input,   output,    pitch);
     61     vp8_short_fdct4x4_c(input + 4, output + 16, pitch);
     62 }
     63 
     64 void vp8_short_walsh4x4_c(short *input, short *output, int pitch)
     65 {
     66     int i;
     67     int a1, b1, c1, d1;
     68     int a2, b2, c2, d2;
     69     short *ip = input;
     70     short *op = output;
     71 
     72 
     73     for (i = 0; i < 4; i++)
     74     {
     75         a1 = ((ip[0] + ip[2])<<2);
     76         d1 = ((ip[1] + ip[3])<<2);
     77         c1 = ((ip[1] - ip[3])<<2);
     78         b1 = ((ip[0] - ip[2])<<2);
     79 
     80         op[0] = a1 + d1 + (a1!=0);
     81         op[1] = b1 + c1;
     82         op[2] = b1 - c1;
     83         op[3] = a1 - d1;
     84         ip += pitch / 2;
     85         op += 4;
     86     }
     87 
     88     ip = output;
     89     op = output;
     90 
     91     for (i = 0; i < 4; i++)
     92     {
     93         a1 = ip[0] + ip[8];
     94         d1 = ip[4] + ip[12];
     95         c1 = ip[4] - ip[12];
     96         b1 = ip[0] - ip[8];
     97 
     98         a2 = a1 + d1;
     99         b2 = b1 + c1;
    100         c2 = b1 - c1;
    101         d2 = a1 - d1;
    102 
    103         a2 += a2<0;
    104         b2 += b2<0;
    105         c2 += c2<0;
    106         d2 += d2<0;
    107 
    108         op[0] = (a2+3) >> 3;
    109         op[4] = (b2+3) >> 3;
    110         op[8] = (c2+3) >> 3;
    111         op[12]= (d2+3) >> 3;
    112 
    113         ip++;
    114         op++;
    115     }
    116 }
    117