Fix silent truncations when extracting values from CheckedNumeric

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>
 
@@ skipping 19 matching lines @@
 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::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 354 matching lines @@
 template <typename Dst, typename Src, NumericConversionType conversion>
 struct TestNumericConversion {};
 
 // 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::min()) >= 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::max()) <= SrcLimits::min()),
+                "");
+  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>(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>(static_cast<Src>(1)) != static_cast<Dst>(1)), "");
+  static_assert(
+      !(StrictNumeric<Src>(static_cast<Src>(1)) == static_cast<Dst>(0)), "");
+
+  base::internal::TestCompileTimeConstantSupport();
+}
+
+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...
                   (!(DstLimits::is_integer && SrcLimits::is_iec559) &&
                    // Same sign, same numeric, source is narrower or same.
                    ((SrcLimits::is_signed == DstLimits::is_signed &&
                     sizeof(Dst) >= sizeof(Src)) ||
                    // Or signed destination and source is smaller
                     (DstLimits::is_signed && sizeof(Dst) > sizeof(Src)))),
                   "Comparison must be sign preserving and value preserving");
 
+    TestStrictComparison<Dst, Src>();
+
     const CheckedNumeric<Dst> checked_dst = SrcLimits::max();
     TEST_EXPECTED_SUCCESS(checked_dst);
     if (MaxExponent<Dst>::value > MaxExponent<Src>::value) {
       if (MaxExponent<Dst>::value >= MaxExponent<Src>::value * 2 - 1) {
         // At least twice larger type.
         TEST_EXPECTED_SUCCESS(SrcLimits::max() * checked_dst);
 
       } else {  // Larger, but not at least twice as large.
         TEST_EXPECTED_FAILURE(SrcLimits::max() * checked_dst);
         TEST_EXPECTED_SUCCESS(checked_dst + 1);
@@ skipping 20 matching lines @@
 struct TestNumericConversion<Dst, Src, SIGN_PRESERVING_NARROW> {
   static void Test(const char *dst, const char *src, int line) {
     typedef numeric_limits<Src> SrcLimits;
     typedef numeric_limits<Dst> DstLimits;
     static_assert(SrcLimits::is_signed == DstLimits::is_signed,
                   "Destination and source sign must be the same");
     static_assert(sizeof(Dst) < sizeof(Src) ||
                    (DstLimits::is_integer && SrcLimits::is_iec559),
                   "Destination must be narrower than source");
 
+    TestStrictComparison<Dst, Src>();
+
     const CheckedNumeric<Dst> checked_dst;
     TEST_EXPECTED_FAILURE(checked_dst + SrcLimits::max());
     TEST_EXPECTED_VALUE(1, checked_dst + static_cast<Src>(1));
     TEST_EXPECTED_FAILURE(checked_dst - SrcLimits::max());
 
     TEST_EXPECTED_RANGE(RANGE_OVERFLOW, SrcLimits::max());
     TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(1));
     if (SrcLimits::is_iec559) {
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::max() * -1);
       TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(-1));
@@ skipping 26 matching lines @@
 template <typename Dst, typename Src>
 struct TestNumericConversion<Dst, Src, SIGN_TO_UNSIGN_WIDEN_OR_EQUAL> {
   static void Test(const char *dst, const char *src, int line) {
     typedef numeric_limits<Src> SrcLimits;
     typedef numeric_limits<Dst> DstLimits;
     static_assert(sizeof(Dst) >= sizeof(Src),
                   "Destination must be equal or wider than source.");
     static_assert(SrcLimits::is_signed, "Source must be signed");
     static_assert(!DstLimits::is_signed, "Destination must be unsigned");
 
+    TestStrictComparison<Dst, Src>();
+
     const CheckedNumeric<Dst> checked_dst;
     TEST_EXPECTED_VALUE(SrcLimits::max(), checked_dst + SrcLimits::max());
     TEST_EXPECTED_FAILURE(checked_dst + static_cast<Src>(-1));
     TEST_EXPECTED_FAILURE(checked_dst + -SrcLimits::max());
 
     TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::min());
     TEST_EXPECTED_RANGE(RANGE_VALID, SrcLimits::max());
     TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(1));
     TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, static_cast<Src>(-1));
   }
 };
 
 template <typename Dst, typename Src>
 struct TestNumericConversion<Dst, Src, SIGN_TO_UNSIGN_NARROW> {
   static void Test(const char *dst, const char *src, int line) {
     typedef numeric_limits<Src> SrcLimits;
     typedef numeric_limits<Dst> DstLimits;
     static_assert((DstLimits::is_integer && SrcLimits::is_iec559) ||
                    (sizeof(Dst) < sizeof(Src)),
                   "Destination must be narrower than source.");
     static_assert(SrcLimits::is_signed, "Source must be signed.");
     static_assert(!DstLimits::is_signed, "Destination must be unsigned.");
 
+    TestStrictComparison<Dst, Src>();
+
     const CheckedNumeric<Dst> checked_dst;
     TEST_EXPECTED_VALUE(1, checked_dst + static_cast<Src>(1));
     TEST_EXPECTED_FAILURE(checked_dst + SrcLimits::max());
     TEST_EXPECTED_FAILURE(checked_dst + static_cast<Src>(-1));
     TEST_EXPECTED_FAILURE(checked_dst + -SrcLimits::max());
 
     TEST_EXPECTED_RANGE(RANGE_OVERFLOW, SrcLimits::max());
     TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(1));
     TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, static_cast<Src>(-1));
     if (SrcLimits::is_iec559) {
@@ skipping 22 matching lines @@
 template <typename Dst, typename Src>
 struct TestNumericConversion<Dst, Src, UNSIGN_TO_SIGN_NARROW_OR_EQUAL> {
   static void Test(const char *dst, const char *src, int line) {
     typedef numeric_limits<Src> SrcLimits;
     typedef numeric_limits<Dst> DstLimits;
     static_assert(sizeof(Dst) <= sizeof(Src),
                   "Destination must be narrower or equal to source.");
     static_assert(!SrcLimits::is_signed, "Source must be unsigned.");
     static_assert(DstLimits::is_signed, "Destination must be signed.");
 
+    TestStrictComparison<Dst, Src>();
+
     const CheckedNumeric<Dst> checked_dst;
     TEST_EXPECTED_VALUE(1, checked_dst + static_cast<Src>(1));
     TEST_EXPECTED_FAILURE(checked_dst + SrcLimits::max());
     TEST_EXPECTED_VALUE(SrcLimits::min(), checked_dst + SrcLimits::min());
 
     TEST_EXPECTED_RANGE(RANGE_VALID, SrcLimits::min());
     TEST_EXPECTED_RANGE(RANGE_OVERFLOW, SrcLimits::max());
     TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(1));
   }
 };
@@ skipping 157 matching lines @@
   float not_a_number = std::numeric_limits<float>::infinity() -
                        std::numeric_limits<float>::infinity();
   EXPECT_TRUE(std::isnan(not_a_number));
   EXPECT_EQ(0, saturated_cast<int>(not_a_number));
 
   // Test the CheckedNumeric value extractions functions.
   auto int8_min = CheckNum(numeric_limits<int8_t>::min());
   auto int8_max = CheckNum(numeric_limits<int8_t>::max());
   auto double_max = CheckNum(numeric_limits<double>::max());
   static_assert(
-      std::is_same<int16_t, decltype(int8_min.ValueOrDie<int16_t>())>::value,
+      std::is_same<int16_t,
+                   decltype(int8_min.ValueOrDie<int16_t>())::type>::value,
       "ValueOrDie returning incorrect type.");
   static_assert(
       std::is_same<int16_t,
-                   decltype(int8_min.ValueOrDefault<int16_t>(0))>::value,
+                   decltype(int8_min.ValueOrDefault<int16_t>(0))::type>::value,
       "ValueOrDefault returning incorrect type.");
   static_assert(
-      std::is_same<float, decltype(double_max.ValueFloating<float>())>::value,
+      std::is_same<float,
+                   decltype(double_max.ValueFloating<float>())::type>::value,
       "ValueFloating returning incorrect type.");
   EXPECT_FALSE(int8_min.template IsValid<uint8_t>());
   EXPECT_TRUE(int8_max.template IsValid<uint8_t>());
   EXPECT_EQ(static_cast<int>(numeric_limits<int8_t>::min()),
             int8_min.template ValueOrDie<int>());
   EXPECT_TRUE(int8_max.template IsValid<uint32_t>());
   EXPECT_EQ(static_cast<int>(numeric_limits<int8_t>::max()),
             int8_max.template ValueOrDie<int>());
   uint8_t uint8_dest = 0;
   int16_t int16_dest = 0;
@@ skipping 114 matching lines @@
   too_large += d;
   EXPECT_FALSE(too_large.IsValid());
   too_large -= d;
   EXPECT_FALSE(too_large.IsValid());
   too_large /= d;
   EXPECT_FALSE(too_large.IsValid());
 }
 
 TEST(SafeNumerics, VariadicNumericOperations) {
   auto a = CheckAdd(1, 2UL, CheckNum(3LL), 4).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(a)>(10), a);
+  EXPECT_EQ(static_cast<decltype(a)::type>(10), a);
   auto b = CheckSub(CheckNum(20.0), 2UL, 4).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(b)>(14.0), b);
+  EXPECT_EQ(static_cast<decltype(b)::type>(14.0), b);
   auto c = CheckMul(20.0, CheckNum(1), 5, 3UL).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(c)>(300.0), c);
+  EXPECT_EQ(static_cast<decltype(c)::type>(300.0), c);
   auto d = CheckDiv(20.0, 2.0, CheckNum(5LL), -4).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(d)>(-.5), d);
+  EXPECT_EQ(static_cast<decltype(d)::type>(-.5), d);
   auto e = CheckMod(CheckNum(20), 3).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(e)>(2), e);
+  EXPECT_EQ(static_cast<decltype(e)::type>(2), e);
   auto f = CheckLsh(1, CheckNum(2)).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(f)>(4), f);
+  EXPECT_EQ(static_cast<decltype(f)::type>(4), f);
   auto g = CheckRsh(4, CheckNum(2)).ValueOrDie();
-  EXPECT_EQ(static_cast<decltype(g)>(1), g);
+  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)>(1), h);
+  EXPECT_EQ(static_cast<decltype(h)::type>(1), h);
 }