Proton/jxrlib/image/sys/strTransform.c
2020-09-29 14:29:06 -05:00

86 lines
2.5 KiB
C

//*@@@+++@@@@******************************************************************
//
// Copyright © Microsoft Corp.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// • Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// • Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
//*@@@---@@@@******************************************************************
#include "strTransform.h"
/** need to swap b and c **/
/** rounding behavior: [0 0 0 0] <-> [+ - - -]
[+ + + +] <-> [+3/4 - - -]
[- - - -] <-> [- - - -] **/
Void strDCT2x2dn(PixelI *pa, PixelI *pb, PixelI *pc, PixelI *pd)
{
PixelI a, b, c, d, C, t;
a = *pa;
b = *pb;
C = *pc;
d = *pd;
a += d;
b -= C;
t = ((a - b) >> 1);
c = t - d;
d = t - C;
a -= d;
b += c;
*pa = a;
*pb = b;
*pc = c;
*pd = d;
}
Void strDCT2x2up(PixelI *pa, PixelI *pb, PixelI *pc, PixelI *pd)
{
PixelI a, b, c, d, C, t;
a = *pa;
b = *pb;
C = *pc;
d = *pd;
a += d;
b -= C;
t = ((a - b + 1) >> 1);
c = t - d;
d = t - C;
a -= d;
b += c;
*pa = a;
*pb = b;
*pc = c;
*pd = d;
}
Void FOURBUTTERFLY_HARDCODED1(PixelI *p)
{
strDCT2x2dn(&p[0], &p[4], &p[8], &p[12]);
strDCT2x2dn(&p[1], &p[5], &p[9], &p[13]);
strDCT2x2dn(&p[2], &p[6], &p[10], &p[14]);
strDCT2x2dn(&p[3], &p[7], &p[11], &p[15]);
}