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 // Copyright (c) 2017 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include #include "base/macros.h" #include "testing/gtest/include/gtest/gtest.h" #include "ui/gfx/half_float.h" namespace gfx { class HalfFloatTest : public testing::Test { public: union FloatUIntUnion { // this must come first for the initializations below to work uint32_t fUInt; float fFloat; }; // Convert an IEEE 754 half-float to a float value // that we can do math on. float FromHalfFloat(HalfFloat half_float) { int sign = (half_float & 0x8000) ? -1 : 1; int exponent = (half_float >> 10) & 0x1F; int fraction = half_float & 0x3FF; if (exponent == 0) { return powf(2.0f, -24.0f) * fraction; } else if (exponent == 0x1F) { return sign * 1000000000000.0f; } else { return pow(2.0f, exponent - 25) * (0x400 + fraction); } } HalfFloat ConvertTruth(float f) { if (f < 0.0) return 0x8000 | ConvertTruth(-f); int max = 0x8000; int min = 0; while (max - min > 1) { int mid = (min + max) >> 1; if (FromHalfFloat(mid) > f) { max = mid; } else { min = mid; } } float low = FromHalfFloat(min); float high = FromHalfFloat(min + 1); if (f - low <= high - f) { return min; } else { return min + 1; } } HalfFloat Convert(float f) { HalfFloat ret; FloatToHalfFloat(&f, &ret, 1); return ret; } }; TEST_F(HalfFloatTest, NoCrashTest) { Convert(nanf("")); Convert(1.0E30f); Convert(-1.0E30f); Convert(1.0E-30f); Convert(-1.0E-30f); } TEST_F(HalfFloatTest, SimpleTest) { static float test[] = { 0.0f, 1.0f, 10.0f, 1000.0f, 65503.0f, 1.0E-3f, 1.0E-6f, 1.0E-20f, 1.0E-44f, }; for (size_t i = 0; i < arraysize(test); i++) { EXPECT_EQ(ConvertTruth(test[i]), Convert(test[i])) << " float = " << test[i]; if (test[i] != 0.0) { EXPECT_EQ(ConvertTruth(-test[i]), Convert(-test[i])) << " float = " << -test[i]; } } } } // namespace