endian: add

Signed-off-by: Simon Rozman <simon@rozman.si>

include/stdex/endian.hpp

@@ -0,0 +1,104 @@
+/*
+	SPDX-License-Identifier: MIT
+	Copyright © 2023 Amebis
+*/
+
+#pragma once
+
+#ifdef _WIN32
+#include <windows.h>
+#endif
+#include "sal.hpp"
+#include <assert.h>
+#include <stdint.h>
+
+#ifdef _WIN32
+#if REG_DWORD == REG_DWORD_LITTLE_ENDIAN
+#elif REG_DWORD == REG_DWORD_BIG_ENDIAN
+#define BIG_ENDIAN
+#else
+#error Unknown endian
+#endif
+#else
+#include <endian.h>
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define BIG_ENDIAN
+#else
+#error Unknown endian
+#endif
+#endif
+
+namespace stdex
+{
+	inline uint16_t byteswap(_In_ const uint16_t value)
+	{
+	#if _MSC_VER >= 1300
+		return _byteswap_ushort(value);
+	#elif defined(_MSC_VER)
+		uint16_t t = (value & 0x00ff) << 8;
+		t |= (value) >> 8;
+		return t;
+	#else
+		return __builtin_bswap16(value);
+	#endif
+	}
+
+	inline uint32_t byteswap(_In_ const uint32_t value)
+	{
+	#if _MSC_VER >= 1300
+		return _byteswap_ulong(value);
+	#elif defined(_MSC_VER)
+		uint32_t t = (value & 0x000000ff) << 24;
+		t |= (value & 0x0000ff00) << 8;
+		t |= (value & 0x00ff0000) >> 8;
+		t |= (value) >> 24;
+		return t;
+	#else
+		return __builtin_bswap32(value);
+	#endif
+	}
+
+	inline uint64_t byteswap(_In_ const uint64_t value)
+	{
+	#if _MSC_VER >= 1300
+		return _byteswap_uint64(value);
+	#elif defined(_MSC_VER)
+		uint64_t t = (value & 0x00000000000000ff) << 56;
+		t |= (value & 0x000000000000ff00) << 40;
+		t |= (value & 0x0000000000ff0000) << 24;
+		t |= (value & 0x00000000ff000000) << 8;
+		t |= (value & 0x000000ff00000000) >> 8;
+		t |= (value & 0x0000ff0000000000) >> 24;
+		t |= (value & 0x00ff000000000000) >> 40;
+		t |= (value) >> 56;
+		return t;
+	#else
+		return __builtin_bswap64(value);
+	#endif
+	}
+
+	inline int16_t byteswap(_In_ const int16_t value) { return byteswap((uint16_t)value); }
+	inline int32_t byteswap(_In_ const int32_t value) { return byteswap((uint32_t)value); }
+	inline int64_t byteswap(_In_ const int64_t value) { return byteswap((uint64_t)value); }
+
+	inline void byteswap(_Inout_ uint16_t* value) { assert(value); *value = byteswap(*value); }
+	inline void byteswap(_Inout_ uint32_t* value) { assert(value); *value = byteswap(*value); }
+	inline void byteswap(_Inout_ uint64_t* value) { assert(value); *value = byteswap(*value); }
+
+	inline void byteswap(_Inout_ int16_t* value) { byteswap((uint16_t*)value); }
+	inline void byteswap(_Inout_ int32_t* value) { byteswap((uint32_t*)value); }
+	inline void byteswap(_Inout_ int64_t* value) { byteswap((uint64_t*)value); }
+}
+
+#ifdef BIG_ENDIAN
+#define LE2HE(x) stdex::byteswap(x)
+#define BE2HE(x) (x)
+#define HE2LE(x) stdex::byteswap(x)
+#define HE2BE(x) (x)
+#else
+#define LE2HE(x) (x)
+#define BE2HE(x) stdex::byteswap(x)
+#define HE2LE(x) (x)
+#define HE2BE(x) stdex::byteswap(x)
+#endif