142 lines
6.5 KiB
C++
142 lines
6.5 KiB
C++
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/*
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* Copyright 2017 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include <algorithm>
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#include <limits>
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#include "webrtc/base/safe_minmax.h"
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#include "webrtc/test/gtest.h"
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namespace rtc {
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namespace {
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// Functions that check that SafeMin() and SafeMax() return the specified type.
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// The functions that end in "R" use an explicitly given return type.
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template <typename T1, typename T2, typename Tmin, typename Tmax>
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constexpr bool TypeCheckMinMax() {
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return std::is_same<decltype(SafeMin(std::declval<T1>(), std::declval<T2>())),
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Tmin>::value &&
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std::is_same<decltype(SafeMax(std::declval<T1>(), std::declval<T2>())),
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Tmax>::value;
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}
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template <typename T1, typename T2, typename R>
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constexpr bool TypeCheckMinR() {
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return std::is_same<
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decltype(SafeMin<R>(std::declval<T1>(), std::declval<T2>())), R>::value;
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}
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template <typename T1, typename T2, typename R>
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constexpr bool TypeCheckMaxR() {
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return std::is_same<
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decltype(SafeMax<R>(std::declval<T1>(), std::declval<T2>())), R>::value;
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}
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// clang-format off
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// SafeMin/SafeMax: Check that all combinations of signed/unsigned 8/64 bits
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// give the correct default result type.
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static_assert(TypeCheckMinMax< int8_t, int8_t, int8_t, int8_t>(), "");
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static_assert(TypeCheckMinMax< int8_t, uint8_t, int8_t, uint8_t>(), "");
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static_assert(TypeCheckMinMax< int8_t, int64_t, int64_t, int64_t>(), "");
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static_assert(TypeCheckMinMax< int8_t, uint64_t, int8_t, uint64_t>(), "");
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static_assert(TypeCheckMinMax< uint8_t, int8_t, int8_t, uint8_t>(), "");
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static_assert(TypeCheckMinMax< uint8_t, uint8_t, uint8_t, uint8_t>(), "");
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static_assert(TypeCheckMinMax< uint8_t, int64_t, int64_t, int64_t>(), "");
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static_assert(TypeCheckMinMax< uint8_t, uint64_t, uint8_t, uint64_t>(), "");
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static_assert(TypeCheckMinMax< int64_t, int8_t, int64_t, int64_t>(), "");
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static_assert(TypeCheckMinMax< int64_t, uint8_t, int64_t, int64_t>(), "");
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static_assert(TypeCheckMinMax< int64_t, int64_t, int64_t, int64_t>(), "");
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static_assert(TypeCheckMinMax< int64_t, uint64_t, int64_t, uint64_t>(), "");
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static_assert(TypeCheckMinMax<uint64_t, int8_t, int8_t, uint64_t>(), "");
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static_assert(TypeCheckMinMax<uint64_t, uint8_t, uint8_t, uint64_t>(), "");
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static_assert(TypeCheckMinMax<uint64_t, int64_t, int64_t, uint64_t>(), "");
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static_assert(TypeCheckMinMax<uint64_t, uint64_t, uint64_t, uint64_t>(), "");
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// SafeMin/SafeMax: Check that we can use enum types.
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enum DefaultE { kFoo = -17 };
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enum UInt8E : uint8_t { kBar = 17 };
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static_assert(TypeCheckMinMax<unsigned, DefaultE, int, unsigned>(), "");
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static_assert(TypeCheckMinMax<unsigned, UInt8E, uint8_t, unsigned>(), "");
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static_assert(TypeCheckMinMax<DefaultE, UInt8E, int, int>(), "");
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using ld = long double;
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// SafeMin/SafeMax: Check that all floating-point combinations give the
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// correct result type.
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static_assert(TypeCheckMinMax< float, float, float, float>(), "");
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static_assert(TypeCheckMinMax< float, double, double, double>(), "");
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static_assert(TypeCheckMinMax< float, ld, ld, ld>(), "");
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static_assert(TypeCheckMinMax<double, float, double, double>(), "");
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static_assert(TypeCheckMinMax<double, double, double, double>(), "");
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static_assert(TypeCheckMinMax<double, ld, ld, ld>(), "");
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static_assert(TypeCheckMinMax< ld, float, ld, ld>(), "");
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static_assert(TypeCheckMinMax< ld, double, ld, ld>(), "");
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static_assert(TypeCheckMinMax< ld, ld, ld, ld>(), "");
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// clang-format on
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// SafeMin/SafeMax: Check some cases of explicitly specified return type. The
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// commented-out lines give compilation errors due to the requested return type
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// being too small or requiring an int<->float conversion.
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static_assert(TypeCheckMinR<int8_t, int8_t, int16_t>(), "");
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// static_assert(TypeCheckMinR<int8_t, int8_t, float>(), "");
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static_assert(TypeCheckMinR<uint32_t, uint64_t, uint32_t>(), "");
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// static_assert(TypeCheckMaxR<uint64_t, float, float>(), "");
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// static_assert(TypeCheckMaxR<uint64_t, double, float>(), "");
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static_assert(TypeCheckMaxR<uint32_t, int32_t, uint32_t>(), "");
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// static_assert(TypeCheckMaxR<uint32_t, int32_t, int32_t>(), "");
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template <typename T1, typename T2, typename Tmin, typename Tmax>
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constexpr bool CheckMinMax(T1 a, T2 b, Tmin min, Tmax max) {
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return TypeCheckMinMax<T1, T2, Tmin, Tmax>() && SafeMin(a, b) == min &&
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SafeMax(a, b) == max;
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}
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// SafeMin/SafeMax: Check a few values.
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static_assert(CheckMinMax(int8_t{1}, int8_t{-1}, int8_t{-1}, int8_t{1}), "");
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static_assert(CheckMinMax(uint8_t{1}, int8_t{-1}, int8_t{-1}, uint8_t{1}), "");
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static_assert(CheckMinMax(uint8_t{5}, uint64_t{2}, uint8_t{2}, uint64_t{5}),
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"");
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static_assert(CheckMinMax(std::numeric_limits<int32_t>::min(),
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std::numeric_limits<uint32_t>::max(),
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std::numeric_limits<int32_t>::min(),
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std::numeric_limits<uint32_t>::max()),
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"");
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static_assert(CheckMinMax(std::numeric_limits<int32_t>::min(),
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std::numeric_limits<uint16_t>::max(),
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std::numeric_limits<int32_t>::min(),
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int32_t{std::numeric_limits<uint16_t>::max()}),
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"");
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// static_assert(CheckMinMax(1.f, 2, 1.f, 2.f), "");
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static_assert(CheckMinMax(1.f, 0.0, 0.0, 1.0), "");
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} // namespace
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// clang-format off
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// These functions aren't used in the tests, but it's useful to look at the
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// compiler output for them, and verify that (1) the same-signedness *Safe
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// functions result in exactly the same code as their *Ref counterparts, and
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// that (2) the mixed-signedness *Safe functions have just a few extra
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// arithmetic and logic instructions (but no extra control flow instructions).
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int32_t TestMinRef( int32_t a, int32_t b) { return std::min(a, b); }
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uint32_t TestMinRef( uint32_t a, uint32_t b) { return std::min(a, b); }
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int32_t TestMinSafe( int32_t a, int32_t b) { return SafeMin(a, b); }
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int32_t TestMinSafe( int32_t a, uint32_t b) { return SafeMin(a, b); }
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int32_t TestMinSafe(uint32_t a, int32_t b) { return SafeMin(a, b); }
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uint32_t TestMinSafe(uint32_t a, uint32_t b) { return SafeMin(a, b); }
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// clang-format on
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} // namespace rtc
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