Merge pull request Tencent#1331 from JPEWdev/mem-alignment-fix

Fix SIGBUS due to unaligned access

Author: miloyip

include/rapidjson/rapidjson.h

@@ -269,16 +269,11 @@
 /*! \ingroup RAPIDJSON_CONFIG
     \param x pointer to align
 
-    Some machines require strict data alignment. Currently the default uses 4 bytes
-    alignment on 32-bit platforms and 8 bytes alignment for 64-bit platforms.
+    Some machines require strict data alignment. The default is 8 bytes.
     User can customize by defining the RAPIDJSON_ALIGN function macro.
 */
 #ifndef RAPIDJSON_ALIGN
-#if RAPIDJSON_64BIT == 1
-#define RAPIDJSON_ALIGN(x) (((x) + static_cast<uint64_t>(7u)) & ~static_cast<uint64_t>(7u))
-#else
-#define RAPIDJSON_ALIGN(x) (((x) + 3u) & ~3u)
-#endif
+#define RAPIDJSON_ALIGN(x) (((x) + static_cast<size_t>(7u)) & ~static_cast<size_t>(7u))
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////

test/unittest/allocatorstest.cpp

@@ -63,23 +63,21 @@ TEST(Allocator, MemoryPoolAllocator) {
 }
 
 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));
+    if (sizeof(size_t) >= 8) {
+        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));
+    for (uint32_t i = 1; i < 8; i++) {
+        EXPECT_EQ(8u, RAPIDJSON_ALIGN(i));
+        EXPECT_EQ(0xFFFFFFF8u, RAPIDJSON_ALIGN(0xFFFFFFF0u + i));
     }
-#endif
 }
 
 TEST(Allocator, Issue399) {