From 311b48224ff02466a0464d51db2ed0a3a0d6cc3b Mon Sep 17 00:00:00 2001
From: Milo Yip <miloyip@gmail.com>
Date: Tue, 1 Sep 2015 10:05:33 +0800
Subject: [PATCH] Try to fix incorrect 64-bit alignment

Added unit tests for alignment macros.
Fixes #418
---
 include/rapidjson/rapidjson.h    |  6 +++---
 test/unittest/allocatorstest.cpp | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/include/rapidjson/rapidjson.h b/include/rapidjson/rapidjson.h
index b0dabc7..4c4d983 100644
--- a/include/rapidjson/rapidjson.h
+++ b/include/rapidjson/rapidjson.h
@@ -238,13 +238,13 @@
     \param x pointer to align
 
     Some machines require strict data alignment. Currently the default uses 4 bytes
-    alignment. User can customize by defining the RAPIDJSON_ALIGN function macro.,
+    alignment. User can customize by defining the RAPIDJSON_ALIGN function macro.
 */
 #ifndef RAPIDJSON_ALIGN
 #if RAPIDJSON_64BIT == 1
-#define RAPIDJSON_ALIGN(x) ((x + 7u) & ~7u)
+#define RAPIDJSON_ALIGN(x) (((x) + static_cast<uint64_t>(7u)) & ~static_cast<uint64_t>(7u))
 #else
-#define RAPIDJSON_ALIGN(x) ((x + 3u) & ~3u)
+#define RAPIDJSON_ALIGN(x) (((x) + 3u) & ~3u)
 #endif
 #endif
 
diff --git a/test/unittest/allocatorstest.cpp b/test/unittest/allocatorstest.cpp
index 7b4deed..792a88e 100644
--- a/test/unittest/allocatorstest.cpp
+++ b/test/unittest/allocatorstest.cpp
@@ -61,3 +61,23 @@ TEST(Allocator, MemoryPoolAllocator) {
         EXPECT_LE(a.Size(), a.Capacity());
     }
 }
+
+TEST(Allocator, Alignment) {
+#if RAPIDJSON_64BIT == 1
+    EXPECT_EQ(RAPIDJSON_UINT64_C2(0x00000000, 0x00000000), RAPIDJSON_ALIGN(0));
+    for (uint64_t i = 1; i < 8; i++) {
+        EXPECT_EQ(RAPIDJSON_UINT64_C2(0x00000000, 0x00000008), RAPIDJSON_ALIGN(i));
+        EXPECT_EQ(RAPIDJSON_UINT64_C2(0x00000000, 0x00000010), RAPIDJSON_ALIGN(RAPIDJSON_UINT64_C2(0x00000000, 0x00000008) + i));
+        EXPECT_EQ(RAPIDJSON_UINT64_C2(0x00000001, 0x00000000), RAPIDJSON_ALIGN(RAPIDJSON_UINT64_C2(0x00000000, 0xFFFFFFF8) + i));
+        EXPECT_EQ(RAPIDJSON_UINT64_C2(0xFFFFFFFF, 0xFFFFFFF8), RAPIDJSON_ALIGN(RAPIDJSON_UINT64_C2(0xFFFFFFFF, 0xFFFFFFF0) + i));
+    }
+#else
+    EXPECT_EQ(0u, RAPIDJSON_ALIGN(0u));
+    for (uint32_t i = 1; i < 4; i++) {
+        EXPECT_EQ(4u, RAPIDJSON_ALIGN(i));
+        EXPECT_EQ(8u, RAPIDJSON_ALIGN(4u + i));
+        EXPECT_EQ(0xFFFFFFF8u, RAPIDJSON_ALIGN(0xFFFFFFF4u + i));
+        EXPECT_EQ(0xFFFFFFFCu, RAPIDJSON_ALIGN(0xFFFFFFF8u + i));
+    }
+#endif
+}