base/safe_numerics_unittest.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <gtest/gtest.h>
   6
   7 #include <sstream>
   8 #include <vector>
   9
  10 #include "base/safe_numerics.h"
  11
  12 namespace base {
  13 namespace internal {
  14
  15 // This is far (far, far) too slow to run normally, but if you're refactoring
  16 // it might be useful.
  17 // #define RUN_EXHAUSTIVE_TEST
  18
  19 #ifdef RUN_EXHAUSTIVE_TEST
  20
  21 template <class From, class To> void ExhaustiveCheckFromTo() {
  22   fprintf(stderr, ".");
  23   From i = std::numeric_limits<From>::min();
  24   for (;;) {
  25     std::ostringstream str_from, str_to;
  26     str_from << i;
  27     To to = static_cast<To>(i);
  28     str_to << to;
  29     bool strings_equal = str_from.str() == str_to.str();
  30     EXPECT_EQ(IsValidNumericCast<To>(i), strings_equal);
  31     fprintf(stderr, "\r%s vs %s\x1B[K",
  32         str_from.str().c_str(), str_to.str().c_str());
  33     ++i;
  34     // If we wrap, then we've tested everything.
  35     if (i == std::numeric_limits<From>::min())
  36       break;
  37   }
  38 }
  39
  40 template <class From> void ExhaustiveCheckFrom() {
  41   ExhaustiveCheckFromTo<From, short>();
  42   ExhaustiveCheckFromTo<From, unsigned short>();
  43   ExhaustiveCheckFromTo<From, int>();
  44   ExhaustiveCheckFromTo<From, unsigned int>();
  45   ExhaustiveCheckFromTo<From, long long>();
  46   ExhaustiveCheckFromTo<From, unsigned long long>();
  47   ExhaustiveCheckFromTo<From, size_t>();
  48   fprintf(stderr, "\n");
  49 }
  50
  51 #endif
  52
  53
  54 TEST(SafeNumerics, NumericCast) {
  55   int small_positive = 1;
  56   int small_negative = -1;
  57   int large_positive = INT_MAX;
  58   int large_negative = INT_MIN;
  59   size_t size_t_small = 1;
  60   size_t size_t_large = UINT_MAX;
  61
  62   // Narrow signed destination.
  63   EXPECT_TRUE(IsValidNumericCast<signed char>(small_positive));
  64   EXPECT_TRUE(IsValidNumericCast<signed char>(small_negative));
  65   EXPECT_FALSE(IsValidNumericCast<signed char>(large_positive));
  66   EXPECT_FALSE(IsValidNumericCast<signed char>(large_negative));
  67   EXPECT_TRUE(IsValidNumericCast<signed short>(small_positive));
  68   EXPECT_TRUE(IsValidNumericCast<signed short>(small_negative));
  69
  70   // Narrow unsigned destination.
  71   EXPECT_TRUE(IsValidNumericCast<unsigned char>(small_positive));
  72   EXPECT_FALSE(IsValidNumericCast<unsigned char>(small_negative));
  73   EXPECT_FALSE(IsValidNumericCast<unsigned char>(large_positive));
  74   EXPECT_FALSE(IsValidNumericCast<unsigned char>(large_negative));
  75   EXPECT_FALSE(IsValidNumericCast<unsigned short>(small_negative));
  76   EXPECT_FALSE(IsValidNumericCast<unsigned short>(large_negative));
  77
  78   // Same width signed destination.
  79   EXPECT_TRUE(IsValidNumericCast<signed int>(small_positive));
  80   EXPECT_TRUE(IsValidNumericCast<signed int>(small_negative));
  81   EXPECT_TRUE(IsValidNumericCast<signed int>(large_positive));
  82   EXPECT_TRUE(IsValidNumericCast<signed int>(large_negative));
  83
  84   // Same width unsigned destination.
  85   EXPECT_TRUE(IsValidNumericCast<unsigned int>(small_positive));
  86   EXPECT_FALSE(IsValidNumericCast<unsigned int>(small_negative));
  87   EXPECT_TRUE(IsValidNumericCast<unsigned int>(large_positive));
  88   EXPECT_FALSE(IsValidNumericCast<unsigned int>(large_negative));
  89
  90   // Wider signed destination.
  91   EXPECT_TRUE(IsValidNumericCast<long long>(small_positive));
  92   EXPECT_TRUE(IsValidNumericCast<long long>(large_negative));
  93   EXPECT_TRUE(IsValidNumericCast<long long>(small_positive));
  94   EXPECT_TRUE(IsValidNumericCast<long long>(large_negative));
  95
  96   // Wider unsigned destination.
  97   EXPECT_TRUE(IsValidNumericCast<unsigned long long>(small_positive));
  98   EXPECT_FALSE(IsValidNumericCast<unsigned long long>(small_negative));
  99   EXPECT_TRUE(IsValidNumericCast<unsigned long long>(large_positive));
 100   EXPECT_FALSE(IsValidNumericCast<unsigned long long>(large_negative));
 101
 102   // Negative to size_t.
 103   EXPECT_FALSE(IsValidNumericCast<size_t>(small_negative));
 104   EXPECT_FALSE(IsValidNumericCast<size_t>(large_negative));
 105
 106   // From unsigned.
 107   // Small.
 108   EXPECT_TRUE(IsValidNumericCast<signed char>(size_t_small));
 109   EXPECT_TRUE(IsValidNumericCast<unsigned char>(size_t_small));
 110   EXPECT_TRUE(IsValidNumericCast<short>(size_t_small));
 111   EXPECT_TRUE(IsValidNumericCast<unsigned short>(size_t_small));
 112   EXPECT_TRUE(IsValidNumericCast<int>(size_t_small));
 113   EXPECT_TRUE(IsValidNumericCast<unsigned int>(size_t_small));
 114   EXPECT_TRUE(IsValidNumericCast<long long>(size_t_small));
 115   EXPECT_TRUE(IsValidNumericCast<unsigned long long>(size_t_small));
 116
 117   // Large.
 118   EXPECT_FALSE(IsValidNumericCast<signed char>(size_t_large));
 119   EXPECT_FALSE(IsValidNumericCast<unsigned char>(size_t_large));
 120   EXPECT_FALSE(IsValidNumericCast<short>(size_t_large));
 121   EXPECT_FALSE(IsValidNumericCast<unsigned short>(size_t_large));
 122   EXPECT_FALSE(IsValidNumericCast<int>(size_t_large));
 123   EXPECT_TRUE(IsValidNumericCast<unsigned int>(size_t_large));
 124   EXPECT_TRUE(IsValidNumericCast<long long>(size_t_large));
 125   EXPECT_TRUE(IsValidNumericCast<unsigned long long>(size_t_large));
 126
 127   // Various edge cases.
 128   EXPECT_TRUE(IsValidNumericCast<int>(static_cast<short>(SHRT_MIN)));
 129   EXPECT_FALSE(
 130       IsValidNumericCast<unsigned short>(static_cast<short>(SHRT_MIN)));
 131   EXPECT_FALSE(IsValidNumericCast<unsigned short>(SHRT_MIN));
 132
 133   // Confirm that checked_numeric_cast<> actually compiles.
 134   std::vector<int> v;
 135   unsigned int checked_size =
 136       base::checked_numeric_cast<unsigned int>(v.size());
 137   EXPECT_EQ(0u, checked_size);
 138
 139 #ifdef RUN_EXHAUSTIVE_TEST
 140   ExhaustiveCheckFrom<short>();
 141   ExhaustiveCheckFrom<unsigned short>();
 142   ExhaustiveCheckFrom<int>();
 143   ExhaustiveCheckFrom<unsigned int>();
 144   ExhaustiveCheckFrom<long long>();
 145   ExhaustiveCheckFrom<unsigned long long>();
 146   ExhaustiveCheckFrom<size_t>();
 147 #endif
 148 }
 149
 150 }  // namespace internal
 151 }  // namespace base