Fix float to int conversion in base/numerics

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::IsValueInRangeForNumericType;
 using base::SizeT;
 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;
@@ skipping 332 matching lines @@
     TEST_EXPECTED_VALIDITY(RANGE_UNDERFLOW, 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));
       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_iec559) {
+        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>(DstLimits::min()));
+      }
     } else if (SrcLimits::is_signed) {
       TEST_EXPECTED_VALUE(-1, checked_dst - static_cast<Src>(1));
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::min());
       TEST_EXPECTED_RANGE(RANGE_VALID, static_cast<Src>(-1));
     } else {
       TEST_EXPECTED_VALIDITY(RANGE_INVALID, checked_dst - static_cast<Src>(1));
       TEST_EXPECTED_RANGE(RANGE_VALID, SrcLimits::min());
     }
   }
 };
@@ skipping 38 matching lines @@
     TEST_EXPECTED_VALIDITY(RANGE_UNDERFLOW, 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) {
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::max() * -1);
       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_iec559) {
+        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>(DstLimits::min()));
+      }
     } else {
       TEST_EXPECTED_RANGE(RANGE_UNDERFLOW, SrcLimits::min());
     }
   }
 };
 
 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;
@@ skipping 152 matching lines @@
             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);
   EXPECT_EQ(numeric_limits<int>::min(), saturated_cast<int>(double_small_int));
   EXPECT_EQ(numeric_limits<int>::max(), saturated_cast<int>(double_large_int));
 }
 
+TEST(SafeNumerics, IsValueInRangeForNumericType) {

[brucedawson, 2015/09/11 23:23:27]

An additional class of tests would be to generate the various maximums and
confirm that that value converts to float without rounding. This could be done
by going int->float->double and int->double and confirming that the results are
the same, or round-tripping, or doing the conversion and then checking
EM_INEXACT with controlfp to validate that the conversion is exact (eg. can
enable FP exceptions for EM_INEXACT so that we crash if the conversion rounds).

Unfortunately the fiddly IEEE exception stuff is probably all non-portable.

[jschuh, 2015/09/12 00:43:12]

Yup. In a previous iteration I had to add some platform-specific FP handling due
to compiler quirks. Now that I was able to remove it I have no intention of
bringing it back.

+  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()));
+}