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// safe_math_unittest.cc: Unit tests for SafeMath

#include "safe_math.h"
#include "breakpad_googletest_includes.h"

namespace {

using google_breakpad::AddIgnoringOverflow;
using google_breakpad::AddWithOverflowCheck;

TEST(SafeMath, AddOverflowWorksAsIntended) {
  EXPECT_EQ(AddWithOverflowCheck<uint8_t>(0, 0),
            std::make_pair<uint8_t>(0, false));
  EXPECT_EQ(AddWithOverflowCheck<uint8_t>(0, 255),
            std::make_pair<uint8_t>(255, false));
  EXPECT_EQ(AddWithOverflowCheck<uint8_t>(1, 255),
            std::make_pair<uint8_t>(0, true));

  EXPECT_EQ(AddWithOverflowCheck<int8_t>(-128, 127),
            std::make_pair<int8_t>(-1, false));
  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, -128),
            std::make_pair<int8_t>(-1, false));
  EXPECT_EQ(AddWithOverflowCheck<int8_t>(1, -128),
            std::make_pair<int8_t>(-127, false));
  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, -1),
            std::make_pair<int8_t>(126, false));

  EXPECT_EQ(AddWithOverflowCheck<int8_t>(-128, -1),
            std::make_pair<int8_t>(127, true));
  EXPECT_EQ(AddWithOverflowCheck<int8_t>(-128, -128),
            std::make_pair<int8_t>(0, true));
  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, 1),
            std::make_pair<int8_t>(-128, true));
  EXPECT_EQ(AddWithOverflowCheck<int8_t>(127, 127),
            std::make_pair<int8_t>(-2, true));
}

TEST(SafeMath, AddIgnoringOverflowWorksAsIntended) {
  EXPECT_EQ(AddIgnoringOverflow<uint8_t>(0, 0), 0);
  EXPECT_EQ(AddIgnoringOverflow<uint8_t>(0, 255), 255);
  EXPECT_EQ(AddIgnoringOverflow<uint8_t>(1, 255), 0);
}

}  // namespace
