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/*-------------------------------------------------------------------------
* drawElements Base Portability Library
* -------------------------------------
*
* Copyright 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*//*!
* \file
* \brief Testing of deMath functions.
*//*--------------------------------------------------------------------*/
#include "deMath.h"
#include "deRandom.h"
DE_BEGIN_EXTERN_C
static deBool conversionToFloatLosesPrecision (deInt32 x)
{
if (x == -0x7FFFFFFF - 1)
return DE_FALSE;
else if (x < 0)
return conversionToFloatLosesPrecision(-x);
else if (x == 0)
return DE_FALSE;
else if (((deUint32)x & 0x1) == 0)
return conversionToFloatLosesPrecision(x >> 1); /* remove trailing zeros */
else
return x > ((1 << 24) - 1); /* remaining part does not fit in the mantissa? */
}
static void testSingleInt32ToFloat (deInt32 x)
{
/* roundTowardsToNegInf(x) <= round(x) <= roundTowardsPosInf(x). */
/* \note: Need to use inequalities since round(x) returns arbitrary precision floats. */
DE_TEST_ASSERT(deInt32ToFloatRoundToNegInf(x) <= deInt32ToFloat(x));
DE_TEST_ASSERT(deInt32ToFloat(x) <= deInt32ToFloatRoundToPosInf(x));
/* if precision is lost, floor(x) < ceil(x). Else floor(x) == ceil(x) */
if (conversionToFloatLosesPrecision(x))
DE_TEST_ASSERT(deInt32ToFloatRoundToNegInf(x) < deInt32ToFloatRoundToPosInf(x));
else
DE_TEST_ASSERT(deInt32ToFloatRoundToNegInf(x) == deInt32ToFloatRoundToPosInf(x));
/* max one ulp from each other */
if (deInt32ToFloatRoundToNegInf(x) < deInt32ToFloatRoundToPosInf(x))
{
union
{
float f;
deInt32 u;
} v0, v1;
v0.f = deInt32ToFloatRoundToNegInf(x);
v1.f = deInt32ToFloatRoundToPosInf(x);
DE_TEST_ASSERT(v0.u + 1 == v1.u || v0.u == v1.u + 1);
}
}
static void testInt32ToFloat (void)
{
const int numIterations = 2500000;
int sign;
int numBits;
int delta;
int ndx;
deRandom rnd;
deRandom_init(&rnd, 0xdeadbeefu-1);
for (sign = -1; sign < 1; ++sign)
for (numBits = 0; numBits < 32; ++numBits)
for (delta = -2; delta < 3; ++delta)
{
const deInt64 x = (deInt64)(sign == -1 ? (-1) : (+1)) * (1LL << (deInt64)numBits) + (deInt64)delta;
/* would overflow */
if (x > 0x7FFFFFFF || x < -0x7FFFFFFF - 1)
continue;
testSingleInt32ToFloat((deInt32)x);
}
for (ndx = 0; ndx < numIterations; ++ndx)
testSingleInt32ToFloat((deInt32)deRandom_getUint32(&rnd));
}
void deMath_selfTest (void)
{
/* Test Int32ToFloat*(). */
testInt32ToFloat();
}
DE_END_EXTERN_C