Fix float to int conversion in base/numerics

base/numerics/safe_numerics_unittest.cc

Index: base/numerics/safe_numerics_unittest.cc
diff --git a/base/numerics/safe_numerics_unittest.cc b/base/numerics/safe_numerics_unittest.cc
index 6f9a966c0156431e654e71d483d81083fe555690..bad0f5718516b4579f45cf8c4497129a149a0a28 100644
--- a/base/numerics/safe_numerics_unittest.cc
+++ b/base/numerics/safe_numerics_unittest.cc
@@ -18,6 +18,7 @@
 using std::numeric_limits;
 using base::CheckedNumeric;
 using base::checked_cast;
+using base::IsValueInRangeForNumericType;
 using base::SizeT;
 using base::StrictNumeric;
 using base::saturated_cast;
@@ -36,6 +37,26 @@ using base::enable_if;
 #pragma warning(disable:4756)
 #endif
 
+// This is a helper function for finding the maximum value in Src that can be
+// wholy represented as the destination floating-point type.
+template <typename Dst, typename Src>
+Dst GetMaxConvertibleToFloat() {
+  typedef numeric_limits<Dst> DstLimits;
+  typedef numeric_limits<Src> SrcLimits;
+  static_assert(SrcLimits::is_specialized, "Source must be numeric.");
+  static_assert(DstLimits::is_specialized, "Destination must be numeric.");
+  CHECK(DstLimits::is_iec559);
+
+  if (SrcLimits::digits <= DstLimits::digits &&
+      MaxExponent<Src>::value <= MaxExponent<Dst>::value)
+    return SrcLimits::max();
+  Src max = SrcLimits::max() / 2 + (SrcLimits::is_integer ? 1 : 0);
+  while (max != static_cast<Src>(static_cast<Dst>(max))) {
+    max /= 2;
+  }
+  return static_cast<Dst>(max);
+}
+
 // Helper macros to wrap displaying the conversion types and line numbers.
 #define TEST_EXPECTED_VALIDITY(expected, actual)                           \
   EXPECT_EQ(expected, CheckedNumeric<Dst>(actual).validity())              \
@@ -370,6 +391,18 @@ struct TestNumericConversion<Dst, Src, SIGN_PRESERVING_NARROW> {
       TEST_EXPECTED_RANGE(RANGE_OVERFLOW, SrcLimits::infinity());
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::infinity() * -1);
       TEST_EXPECTED_RANGE(RANGE_INVALID, SrcLimits::quiet_NaN());
+      if (DstLimits::is_integer) {
+        if (SrcLimits::digits < DstLimits::digits) {
+          TEST_EXPECTED_RANGE(RANGE_OVERFLOW,
+                              static_cast<Src>(DstLimits::max()));
+        } else {
+          TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(DstLimits::max()));
+        }
+        TEST_EXPECTED_RANGE(
+            RANGE_VALID,
+            static_cast<Src>(GetMaxConvertibleToFloat<Src, Dst>()));
+        TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(DstLimits::min()));
+      }
     } else if (SrcLimits::is_signed) {
       TEST_EXPECTED_VALUE(-1, checked_dst - static_cast<Src>(1));
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::min());
@@ -428,6 +461,18 @@ struct TestNumericConversion<Dst, Src, SIGN_TO_UNSIGN_NARROW> {
       TEST_EXPECTED_RANGE(RANGE_OVERFLOW, SrcLimits::infinity());
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::infinity() * -1);
       TEST_EXPECTED_RANGE(RANGE_INVALID, SrcLimits::quiet_NaN());
+      if (DstLimits::is_integer) {
+        if (SrcLimits::digits < DstLimits::digits) {
+          TEST_EXPECTED_RANGE(RANGE_OVERFLOW,
+                              static_cast<Src>(DstLimits::max()));
+        } else {
+          TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(DstLimits::max()));
+        }
+        TEST_EXPECTED_RANGE(
+            RANGE_VALID,
+            static_cast<Src>(GetMaxConvertibleToFloat<Src, Dst>()));
+        TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(DstLimits::min()));
+      }
     } else {
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::min());
     }
@@ -600,3 +645,77 @@ TEST(SafeNumerics, CastTests) {
   EXPECT_EQ(numeric_limits<int>::max(), saturated_cast<int>(double_large_int));
 }
 
+TEST(SafeNumerics, IsValueInRangeForNumericType) {
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint32_t>(0));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint32_t>(1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint32_t>(2));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint32_t>(-1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint32_t>(0xffffffffu));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint32_t>(UINT64_C(0xffffffff)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint32_t>(UINT64_C(0x100000000)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint32_t>(UINT64_C(0x100000001)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint32_t>(
+      std::numeric_limits<int32_t>::min()));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint32_t>(
+      std::numeric_limits<int64_t>::min()));
+
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(0));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(2));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(-1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(0x7fffffff));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(0x7fffffffu));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(0x80000000u));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(0xffffffffu));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(INT64_C(0x80000000)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(INT64_C(0xffffffff)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(INT64_C(0x100000000)));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(
+      std::numeric_limits<int32_t>::min()));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int32_t>(
+      implicit_cast<int64_t>(std::numeric_limits<int32_t>::min())));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(
+      implicit_cast<int64_t>(std::numeric_limits<int32_t>::min()) - 1));
+  EXPECT_FALSE(IsValueInRangeForNumericType<int32_t>(
+      std::numeric_limits<int64_t>::min()));
+
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(0));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(2));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint64_t>(-1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(0xffffffffu));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(UINT64_C(0xffffffff)));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(UINT64_C(0x100000000)));
+  EXPECT_TRUE(IsValueInRangeForNumericType<uint64_t>(UINT64_C(0x100000001)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint64_t>(
+      std::numeric_limits<int32_t>::min()));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint64_t>(INT64_C(-1)));
+  EXPECT_FALSE(IsValueInRangeForNumericType<uint64_t>(
+      std::numeric_limits<int64_t>::min()));
+
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(0));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(2));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(-1));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(0x7fffffff));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(0x7fffffffu));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(0x80000000u));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(0xffffffffu));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(INT64_C(0x80000000)));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(INT64_C(0xffffffff)));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(INT64_C(0x100000000)));
+  EXPECT_TRUE(
+      IsValueInRangeForNumericType<int64_t>(INT64_C(0x7fffffffffffffff)));
+  EXPECT_TRUE(
+      IsValueInRangeForNumericType<int64_t>(UINT64_C(0x7fffffffffffffff)));
+  EXPECT_FALSE(
+      IsValueInRangeForNumericType<int64_t>(UINT64_C(0x8000000000000000)));
+  EXPECT_FALSE(
+      IsValueInRangeForNumericType<int64_t>(UINT64_C(0xffffffffffffffff)));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(
+      std::numeric_limits<int32_t>::min()));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(
+      implicit_cast<int64_t>(std::numeric_limits<int32_t>::min())));
+  EXPECT_TRUE(IsValueInRangeForNumericType<int64_t>(
+      std::numeric_limits<int64_t>::min()));
+}