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