Add strictly checked numeric types

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.
 
 #if defined(COMPILER_MSVC) && defined(ARCH_CPU_32_BITS)
 #include <mmintrin.h>
 #endif
 #include <stdint.h>
 
 #include <limits>
 
 #include "base/compiler_specific.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/numerics/safe_math.h"
 #include "base/template_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using std::numeric_limits;
 using base::CheckedNumeric;
 using base::checked_cast;
+using base::SSizeT;
+using base::StrictNumeric;
 using base::saturated_cast;
+using base::strict_cast;
 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::enable_if;
 
 // These tests deliberately cause arithmetic overflows. If the compiler is
 // aggressive enough, it can const fold these overflows. Disable warnings about
 // overflows for const expressions.
@@ skipping 521 matching lines @@
 #if defined(COMPILER_MSVC)
 #pragma warning(disable : 4756)
 #endif
 
   int small_positive = 1;
   int small_negative = -1;
   double double_small = 1.0;
   double double_large = numeric_limits<double>::max();
   double double_infinity = numeric_limits<float>::infinity();
 
-  // Just test that the cast compiles, since the other tests cover logic.
+  // Just test that the casts compile, since the other tests cover logic.
   EXPECT_EQ(0, checked_cast<int>(static_cast<size_t>(0)));
+  EXPECT_EQ(0, strict_cast<int>(static_cast<char>(0)));
+  EXPECT_EQ(0, strict_cast<int>(static_cast<unsigned char>(0)));
+  EXPECT_EQ(0U, strict_cast<unsigned>(static_cast<unsigned char>(0)));
+  EXPECT_EQ(1ULL, static_cast<uint64_t>(StrictNumeric<size_t>(1U)));
+  EXPECT_EQ(1ULL, static_cast<uint64_t>(SSizeT(1U)));
+  EXPECT_EQ(1U, static_cast<size_t>(StrictNumeric<unsigned>(1U)));
+
+  // These casts and coercions will fail to compile:
+  // EXPECT_EQ(0, strict_cast<int>(static_cast<size_t>(0)));
+  // EXPECT_EQ(0, strict_cast<size_t>(static_cast<int>(0)));
+  // EXPECT_EQ(1ULL, StrictNumeric<size_t>(1));
+  // EXPECT_EQ(1, StrictNumeric<size_t>(1U));
 
   // Test various saturation corner cases.
   EXPECT_EQ(saturated_cast<int>(small_negative),
             static_cast<int>(small_negative));
   EXPECT_EQ(saturated_cast<int>(small_positive),
             static_cast<int>(small_positive));
   EXPECT_EQ(saturated_cast<unsigned>(small_negative),
             static_cast<unsigned>(0));
   EXPECT_EQ(saturated_cast<int>(double_small),
             static_cast<int>(double_small));
   EXPECT_EQ(saturated_cast<int>(double_large), numeric_limits<int>::max());
   EXPECT_EQ(saturated_cast<float>(double_large), double_infinity);
   EXPECT_EQ(saturated_cast<float>(-double_large), -double_infinity);
 }