Initial commit of all the NXT integration.

More like squashed history, contributors were:
 - Kai Ninomiya
 - Corentin Wallez

src/backend/tests/MathTests.cpp

@@ -0,0 +1,85 @@
+// Copyright 2017 The NXT Authors
+//
+// 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 <gtest/gtest.h>
+
+#include "common/Math.h"
+
+using namespace backend;
+
+// Tests for ScanForward
+TEST(Math, ScanForward) {
+    // Test extrema
+    ASSERT_EQ(ScanForward(1), 0);
+    ASSERT_EQ(ScanForward(0x8000000000000000), 63);
+
+    // Test with more than one bit set.
+    ASSERT_EQ(ScanForward(256), 8);
+    ASSERT_EQ(ScanForward(256 + 32), 5);
+    ASSERT_EQ(ScanForward(1024 + 256 + 32), 5);
+}
+
+// Tests for Log2
+TEST(Math, Log2) {
+    // Test extrema
+    ASSERT_EQ(Log2(1), 0);
+    ASSERT_EQ(Log2(0xFFFFFFFF), 31);
+
+    // Test boundary between two logs
+    ASSERT_EQ(Log2(0x80000000), 31);
+    ASSERT_EQ(Log2(0x7FFFFFFF), 30);
+
+    ASSERT_EQ(Log2(16), 4);
+    ASSERT_EQ(Log2(15), 3);
+}
+
+// Tests for IsPowerOfTwo
+TEST(Math, IsPowerOfTwo) {
+    ASSERT_TRUE(IsPowerOfTwo(1));
+    ASSERT_TRUE(IsPowerOfTwo(2));
+    ASSERT_FALSE(IsPowerOfTwo(3));
+
+    ASSERT_TRUE(IsPowerOfTwo(0x8000000));
+    ASSERT_FALSE(IsPowerOfTwo(0x8000400));
+}
+
+// Tests for Align
+TEST(Math, Align) {
+    constexpr size_t kTestAlignment = 8;
+
+    char buffer[kTestAlignment * 4];
+
+    for (size_t i = 0; i < 2 * kTestAlignment; ++i) {
+        char* unaligned = &buffer[i];
+        char* aligned = Align(unaligned, kTestAlignment);
+
+        ASSERT_GE(aligned - unaligned, 0);
+        ASSERT_LT(aligned - unaligned, kTestAlignment);
+        ASSERT_EQ(reinterpret_cast<intptr_t>(aligned) & (kTestAlignment -1), 0);
+    }
+}
+
+// Tests for IsAligned
+TEST(Math, IsAligned) {
+    constexpr size_t kTestAlignment = 8;
+
+    char buffer[kTestAlignment * 4];
+
+    for (size_t i = 0; i < 2 * kTestAlignment; ++i) {
+        char* unaligned = &buffer[i];
+        char* aligned = Align(unaligned, kTestAlignment);
+
+        ASSERT_EQ(IsAligned(unaligned, kTestAlignment), unaligned == aligned);
+    }
+}