The Tor Browser: media/libvpx/vp8/encoder/dct.c@ac0c01689b40

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     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  */

    12 #include <math.h>

    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;

    21     for (i = 0; i < 4; i++)

    22     {

    23         a1 = ((ip[0] + ip[3]) * 8);

    24         b1 = ((ip[1] + ip[2]) * 8);

    25         c1 = ((ip[1] - ip[2]) * 8);

    26         d1 = ((ip[0] - ip[3]) * 8);

    28         op[0] = a1 + b1;

    29         op[2] = a1 - b1;

    31         op[1] = (c1 * 2217 + d1 * 5352 +  14500)>>12;

    32         op[3] = (d1 * 2217 - c1 * 5352 +   7500)>>12;

    34         ip += pitch / 2;

    35         op += 4;

    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];

    47         op[0]  = ( a1 + b1 + 7)>>4;

    48         op[8]  = ( a1 - b1 + 7)>>4;

    50         op[4]  =((c1 * 2217 + d1 * 5352 +  12000)>>16) + (d1!=0);

    51         op[12] = (d1 * 2217 - c1 * 5352 +  51000)>>16;

    53         ip++;

    54         op++;

    55     }

    56 }

    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 }

    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;

    73     for (i = 0; i < 4; i++)

    74     {

    75         a1 = ((ip[0] + ip[2]) * 4);

    76         d1 = ((ip[1] + ip[3]) * 4);

    77         c1 = ((ip[1] - ip[3]) * 4);

    78         b1 = ((ip[0] - ip[2]) * 4);

    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     }

    88     ip = output;

    89     op = output;

    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];

    98         a2 = a1 + d1;

    99         b2 = b1 + c1;

   100         c2 = b1 - c1;

   101         d2 = a1 - d1;

   103         a2 += a2<0;

   104         b2 += b2<0;

   105         c2 += c2<0;

   106         d2 += d2<0;

   108         op[0] = (a2+3) >> 3;

   109         op[4] = (b2+3) >> 3;

   110         op[8] = (c2+3) >> 3;

   111         op[12]= (d2+3) >> 3;

   113         ip++;

   114         op++;

   115     }

   116 }

The Tor Browser / file revision

media/libvpx/vp8/encoder/dct.c@ac0c01689b40

media/libvpx/vp8/encoder/dct.c