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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Fuzz.h"
// This really is just an example Fuzz*.cpp file.
// It tests that two different ways of calculating the Paeth predictor function are equivalent.
static uint8_t paeth_std(uint8_t a, uint8_t b, uint8_t c) {
int p = a+b-c;
int pa = abs(p-a),
pb = abs(p-b),
pc = abs(p-c);
if (pb < pa) { pa = pb; a = b; }
if (pc < pa) { a = c; }
return a;
}
static uint8_t paeth_alt(uint8_t a, uint8_t b, uint8_t c) {
int min = SkTMin(a,b),
max = SkTMax(a,b);
int delta = (max-min)/3;
if (c <= min+delta) return max;
if (c >= max-delta) return min;
return c;
}
DEF_FUZZ(Paeth, fuzz) {
auto a = fuzz->nextB(),
b = fuzz->nextB(),
c = fuzz->nextB();
ASSERT(paeth_alt(a,b,c) == paeth_std(a,b,c));
}
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