Add uint128_struct and its test

util/numeric/int128_test.cc

+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/numeric/int128.h"
+
+#include "base/basictypes.h"
+#include "gtest/gtest.h"
+
+namespace {
+
+using namespace crashpad;
+
+TEST(Int128, UInt128) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  const uint8_t kBytes[] =
+      {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
+#else
+  const uint8_t kBytes[] =
+      {15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
+#endif
+
+  uint128_struct uint128;
+  COMPILE_ASSERT(sizeof(uint128) == sizeof(kBytes), sizes_must_be_equal);

[Robert Sesek, 2014/09/22 19:02:14]

Maybe also something simpler: COMPILE_ASSERT(8 * sizeof(uint128) == 128).

[Mark Mentovai, 2014/09/22 19:41:20]

rsesek wrote:
Well, I’m testing that it’s safe to bit_cast between the two, so I wanted to
have both variables in the expression.

[Robert Sesek, 2014/09/22 19:46:12]

I meant "in addition to".

+
+  uint128 = bit_cast<uint128_struct>(kBytes);
+
+  EXPECT_EQ(0x0706050403020100u, uint128.lo);
+  EXPECT_EQ(0x0f0e0d0c0b0a0908u, uint128.hi);
+}
+
+}  // namespace