Add support for CheckedNumeric Max and Min constexpr functions

base/numerics/safe_numerics_unittest.cc

 // Copyright 2013 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 <stddef.h>
 #include <stdint.h>
 
 #include <limits>
 #include <type_traits>
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/numerics/safe_math.h"
 #include "base/test/gtest_util.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS)
 #include <mmintrin.h>
 #endif
 
 using std::numeric_limits;
 using base::CheckedNumeric;
 using base::IsValidForType;
 using base::ValueOrDieForType;
 using base::ValueOrDefaultForType;
 using base::CheckNum;
+using base::CheckMax;
+using base::CheckMin;
 using base::CheckAdd;
 using base::CheckSub;
 using base::CheckMul;
 using base::CheckDiv;
 using base::CheckMod;
 using base::CheckLsh;
 using base::CheckRsh;
 using base::checked_cast;
 using base::IsValueInRangeForNumericType;
 using base::IsValueNegative;
 using base::SizeT;
 using base::StrictNumeric;
+using base::MakeStrictNum;
 using base::saturated_cast;
 using base::strict_cast;
-using base::StrictNumeric;
 using base::internal::MaxExponent;
 using base::internal::RANGE_VALID;
 using base::internal::RANGE_INVALID;
 using base::internal::RANGE_OVERFLOW;
 using base::internal::RANGE_UNDERFLOW;
 using base::internal::SignedIntegerForSize;
 
 // These tests deliberately cause arithmetic boundary errors. If the compiler is
 // aggressive enough, it can const detect these errors, so we disable warnings.
 #if defined(OS_WIN)
@@ skipping 377 matching lines @@
 // EXPECT_EQ wrappers providing specific detail on test failures.
 #define TEST_EXPECTED_RANGE(expected, actual)                                  \
   EXPECT_EQ(expected, base::internal::DstRangeRelationToSrcRange<Dst>(actual)) \
       << "Conversion test: " << src << " value " << actual << " to " << dst    \
       << " on line " << line
 
 template <typename Dst, typename Src>
 void TestStrictComparison() {
   typedef numeric_limits<Dst> DstLimits;
   typedef numeric_limits<Src> SrcLimits;
-  static_assert(StrictNumeric<Src>(SrcLimits::min()) < DstLimits::max(), "");
-  static_assert(StrictNumeric<Src>(SrcLimits::min()) < SrcLimits::max(), "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::min()) >= DstLimits::max()),
+  static_assert(StrictNumeric<Src>(SrcLimits::lowest()) < DstLimits::max(), "");
+  static_assert(StrictNumeric<Src>(SrcLimits::lowest()) < SrcLimits::max(), "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::lowest()) >= DstLimits::max()),
                 "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::min()) >= SrcLimits::max()),
+  static_assert(!(StrictNumeric<Src>(SrcLimits::lowest()) >= SrcLimits::max()),
                 "");
-  static_assert(StrictNumeric<Src>(SrcLimits::min()) <= DstLimits::max(), "");
-  static_assert(StrictNumeric<Src>(SrcLimits::min()) <= SrcLimits::max(), "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::min()) > DstLimits::max()), "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::min()) > SrcLimits::max()), "");
-  static_assert(StrictNumeric<Src>(SrcLimits::max()) > DstLimits::min(), "");
-  static_assert(StrictNumeric<Src>(SrcLimits::max()) > SrcLimits::min(), "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) <= DstLimits::min()),
+  static_assert(StrictNumeric<Src>(SrcLimits::lowest()) <= DstLimits::max(),
                 "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) <= SrcLimits::min()),
+  static_assert(StrictNumeric<Src>(SrcLimits::lowest()) <= SrcLimits::max(),
                 "");
-  static_assert(StrictNumeric<Src>(SrcLimits::max()) >= DstLimits::min(), "");
-  static_assert(StrictNumeric<Src>(SrcLimits::max()) >= SrcLimits::min(), "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) < DstLimits::min()), "");
-  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) < SrcLimits::min()), "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::lowest()) > DstLimits::max()),
+                "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::lowest()) > SrcLimits::max()),
+                "");
+  static_assert(StrictNumeric<Src>(SrcLimits::max()) > DstLimits::lowest(), "");
+  static_assert(StrictNumeric<Src>(SrcLimits::max()) > SrcLimits::lowest(), "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) <= DstLimits::lowest()),
+                "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) <= SrcLimits::lowest()),
+                "");
+  static_assert(StrictNumeric<Src>(SrcLimits::max()) >= DstLimits::lowest(),
+                "");
+  static_assert(StrictNumeric<Src>(SrcLimits::max()) >= SrcLimits::lowest(),
+                "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) < DstLimits::lowest()),
+                "");
+  static_assert(!(StrictNumeric<Src>(SrcLimits::max()) < SrcLimits::lowest()),
+                "");
   static_assert(StrictNumeric<Src>(static_cast<Src>(1)) == static_cast<Dst>(1),
                 "");
   static_assert(StrictNumeric<Src>(static_cast<Src>(1)) != static_cast<Dst>(0),
                 "");
   static_assert(StrictNumeric<Src>(SrcLimits::max()) != static_cast<Dst>(0),
                 "");
-  static_assert(StrictNumeric<Src>(SrcLimits::max()) != DstLimits::min(), "");
+  static_assert(StrictNumeric<Src>(SrcLimits::max()) != DstLimits::lowest(),
+                "");
   static_assert(
       !(StrictNumeric<Src>(static_cast<Src>(1)) != static_cast<Dst>(1)), "");
   static_assert(
       !(StrictNumeric<Src>(static_cast<Src>(1)) == static_cast<Dst>(0)), "");
+
+  // Due to differences in float handling between compilers, these aren't
+  // compile-time constants everywhere. So, we use run-time tests.
+  EXPECT_EQ(SrcLimits::max(),
+            CheckNum(SrcLimits::max()).Max(DstLimits::lowest()).ValueOrDie());
+  EXPECT_EQ(DstLimits::max(),
+            CheckNum(SrcLimits::lowest()).Max(DstLimits::max()).ValueOrDie());
+  EXPECT_EQ(DstLimits::lowest(),
+            CheckNum(SrcLimits::max()).Min(DstLimits::lowest()).ValueOrDie());
+  EXPECT_EQ(SrcLimits::lowest(),
+            CheckNum(SrcLimits::lowest()).Min(DstLimits::max()).ValueOrDie());
+  EXPECT_EQ(SrcLimits::lowest(), CheckMin(MakeStrictNum(1), CheckNum(0),
+                                          DstLimits::max(), SrcLimits::lowest())
+                                     .ValueOrDie());
+  EXPECT_EQ(DstLimits::max(), CheckMax(MakeStrictNum(1), CheckNum(0),
+                                       DstLimits::max(), SrcLimits::lowest())
+                                  .ValueOrDie());
 }
 
 template <typename Dst, typename Src>
 struct TestNumericConversion<Dst, Src, SIGN_PRESERVING_VALUE_PRESERVING> {
   static void Test(const char *dst, const char *src, int line) {
     typedef numeric_limits<Src> SrcLimits;
     typedef numeric_limits<Dst> DstLimits;
                    // Integral to floating.
     static_assert((DstLimits::is_iec559 && SrcLimits::is_integer) ||
                   // Not floating to integral and...
@@ skipping 515 matching lines @@
   EXPECT_EQ(static_cast<decltype(d)::type>(-.5), d);
   auto e = CheckMod(CheckNum(20), 3).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(e)::type>(2), e);
   auto f = CheckLsh(1, CheckNum(2)).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(f)::type>(4), f);
   auto g = CheckRsh(4, CheckNum(2)).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(g)::type>(1), g);
   auto h = CheckRsh(CheckAdd(1, 1, 1, 1), CheckSub(4, 2)).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(h)::type>(1), h);
 }