Merge pull request #13874 from sepalani/bitcast-ptr

Common/BitUtils: Add operator[] to BitCastPtrType

1 files changed, 52 insertions, 0 deletions

diff --git a/Source/UnitTests/Common/BitUtilsTest.cpp b/Source/UnitTests/Common/BitUtilsTest.cpp
index 8244941cf8..a140d07f54 100644
--- a/Source/UnitTests/Common/BitUtilsTest.cpp
+++ b/Source/UnitTests/Common/BitUtilsTest.cpp
@@ -3,6 +3,9 @@
 
 #include <gtest/gtest.h>
 
+#include <bit>
+#include <vector>
+
 #include "Common/BitUtils.h"
 #include "Common/CommonTypes.h"
 
@@ -88,3 +91,52 @@ TEST(BitUtils, IsValidLowMask)
   EXPECT_FALSE(Common::IsValidLowMask((u64) ~(0b10000)));
   EXPECT_FALSE(Common::IsValidLowMask((u64)(~((u64)(~0b0) >> 1) | 0b1111)));
 }
+
+TEST(BitUtils, BitCastPtr)
+{
+  EXPECT_EQ(std::endian::native, std::endian::little);
+
+  std::vector<u8> data{0, 1, 0, 2, 0, 3, 0, 0xFF, 0xFF};
+  u8* buffer = data.data();
+
+  EXPECT_EQ(s16(1), Common::BitCastPtr<s16>(buffer + 1));
+  Common::BitCastPtr<s16>(buffer + 1) = s16(-1);
+  EXPECT_EQ(u16(0xFFFF), Common::BitCastPtr<u16>(buffer + 1));
+  EXPECT_EQ(data, std::vector<u8>({0, 0xFF, 0xFF, 2, 0, 3, 0, 0xFF, 0xFF}));
+
+  EXPECT_EQ(s32(0xFFFF0003), Common::BitCastPtr<s32>(buffer + 1)[1]);
+  Common::BitCastPtr<u32>(buffer + 1)[1] = u32(0xFFFFFFFF);
+  EXPECT_EQ(s32(-1), Common::BitCastPtr<s32>(buffer + 1)[1]);
+  EXPECT_EQ(data, std::vector<u8>({0, 0xFF, 0xFF, 2, 0, 0xFF, 0xFF, 0xFF, 0xFF}));
+
+#pragma pack(push, 1)
+  struct MyStruct
+  {
+    u16 v16;
+    u8 v8;
+  };
+#pragma pack(pop)
+
+  MyStruct s1 = Common::BitCastPtr<MyStruct>(buffer + 1);
+  EXPECT_EQ(u16(0xFFFF), s1.v16);
+  EXPECT_EQ(u8(2), s1.v8);
+  s1.v16 = 4;
+  s1.v8 = 5;
+  Common::BitCastPtr<MyStruct>(buffer + 1) = s1;
+  EXPECT_EQ(s16(4), Common::BitCastPtr<s16>(buffer + 1));
+  EXPECT_EQ(s8(5), Common::BitCastPtr<s8>(buffer + 3));
+  EXPECT_EQ(data, std::vector<u8>({0, 4, 0, 5, 0, 0xFF, 0xFF, 0xFF, 0xFF}));
+
+  auto struct_array = Common::BitCastPtr<MyStruct>(buffer + 1);
+  const MyStruct s1_again = struct_array[0];
+  EXPECT_EQ(u16(4), s1_again.v16);
+  EXPECT_EQ(u8(5), s1_again.v8);
+  MyStruct s2 = struct_array[1];
+  EXPECT_EQ(u16(0xFF00), s2.v16);
+  EXPECT_EQ(u8(0xFF), s2.v8);
+  struct_array[1] = s1_again;
+  s2 = struct_array[1];
+  EXPECT_EQ(u16(4), s2.v16);
+  EXPECT_EQ(u8(5), s2.v8);
+  EXPECT_EQ(data, std::vector<u8>({0, 4, 0, 5, 4, 0, 5, 0xFF, 0xFF}));
+}