godot/modules/fbx/fbx_parser/ByteSwapper.h

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/*  ByteSwapper.h                                                        */
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/*
Open Asset Import Library (assimp)
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  following disclaimer.

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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

/** @file Helper class to perform various byte order swappings
   (e.g. little to big endian) */

#ifndef BYTESWAPPER_H
#define BYTESWAPPER_H

#include <stdint.h>
#include <algorithm>
#include <locale>

namespace FBXDocParser {
// --------------------------------------------------------------------------------------
/** Defines some useful byte order swap routines.
 *
 * This is required to read big-endian model formats on little-endian machines,
 * and vice versa. Direct use of this class is DEPRECATED. Use #StreamReader instead. */
// --------------------------------------------------------------------------------------
class ByteSwap {
	ByteSwap() {}

public:
	// ----------------------------------------------------------------------
	/** Swap two bytes of data
	 *  @param[inout] _szOut A void* to save the reintcasts for the caller. */
	static inline void Swap2(void *_szOut) {
		uint8_t *const szOut = reinterpret_cast<uint8_t *>(_szOut);
		std::swap(szOut[0], szOut[1]);
	}

	// ----------------------------------------------------------------------
	/** Swap four bytes of data
	 *  @param[inout] _szOut A void* to save the reintcasts for the caller. */
	static inline void Swap4(void *_szOut) {
		uint8_t *const szOut = reinterpret_cast<uint8_t *>(_szOut);
		std::swap(szOut[0], szOut[3]);
		std::swap(szOut[1], szOut[2]);
	}

	// ----------------------------------------------------------------------
	/** Swap eight bytes of data
	 *  @param[inout] _szOut A void* to save the reintcasts for the caller. */
	static inline void Swap8(void *_szOut) {
		uint8_t *const szOut = reinterpret_cast<uint8_t *>(_szOut);
		std::swap(szOut[0], szOut[7]);
		std::swap(szOut[1], szOut[6]);
		std::swap(szOut[2], szOut[5]);
		std::swap(szOut[3], szOut[4]);
	}

	// ----------------------------------------------------------------------
	/** ByteSwap a float. Not a joke.
	 *  @param[inout] fOut ehm. .. */
	static inline void Swap(float *fOut) {
		Swap4(fOut);
	}

	// ----------------------------------------------------------------------
	/** ByteSwap a double. Not a joke.
	 *  @param[inout] fOut ehm. .. */
	static inline void Swap(double *fOut) {
		Swap8(fOut);
	}

	// ----------------------------------------------------------------------
	/** ByteSwap an int16t. Not a joke.
	 *  @param[inout] fOut ehm. .. */
	static inline void Swap(int16_t *fOut) {
		Swap2(fOut);
	}

	static inline void Swap(uint16_t *fOut) {
		Swap2(fOut);
	}

	// ----------------------------------------------------------------------
	/** ByteSwap an int32t. Not a joke.
	 *  @param[inout] fOut ehm. .. */
	static inline void Swap(int32_t *fOut) {
		Swap4(fOut);
	}

	static inline void Swap(uint32_t *fOut) {
		Swap4(fOut);
	}

	// ----------------------------------------------------------------------
	/** ByteSwap an int64t. Not a joke.
	 *  @param[inout] fOut ehm. .. */
	static inline void Swap(int64_t *fOut) {
		Swap8(fOut);
	}

	static inline void Swap(uint64_t *fOut) {
		Swap8(fOut);
	}

	// ----------------------------------------------------------------------
	//! Templatized ByteSwap
	//! \returns param tOut as swapped
	template <typename Type>
	static inline Type Swapped(Type tOut) {
		return _swapper<Type, sizeof(Type)>()(tOut);
	}

private:
	template <typename T, size_t size>
	struct _swapper;
};

template <typename T>
struct ByteSwap::_swapper<T, 2> {
	T operator()(T tOut) {
		Swap2(&tOut);
		return tOut;
	}
};

template <typename T>
struct ByteSwap::_swapper<T, 4> {
	T operator()(T tOut) {
		Swap4(&tOut);
		return tOut;
	}
};

template <typename T>
struct ByteSwap::_swapper<T, 8> {
	T operator()(T tOut) {
		Swap8(&tOut);
		return tOut;
	}
};

// --------------------------------------------------------------------------------------
// ByteSwap macros for BigEndian/LittleEndian support
// --------------------------------------------------------------------------------------
#if (defined AI_BUILD_BIG_ENDIAN)
#define AI_LE(t) (t)
#define AI_BE(t) ByteSwap::Swapped(t)
#define AI_LSWAP2(p)
#define AI_LSWAP4(p)
#define AI_LSWAP8(p)
#define AI_LSWAP2P(p)
#define AI_LSWAP4P(p)
#define AI_LSWAP8P(p)
#define LE_NCONST const
#define AI_SWAP2(p) ByteSwap::Swap2(&(p))
#define AI_SWAP4(p) ByteSwap::Swap4(&(p))
#define AI_SWAP8(p) ByteSwap::Swap8(&(p))
#define AI_SWAP2P(p) ByteSwap::Swap2((p))
#define AI_SWAP4P(p) ByteSwap::Swap4((p))
#define AI_SWAP8P(p) ByteSwap::Swap8((p))
#define BE_NCONST
#else
#define AI_BE(t) (t)
#define AI_LE(t) ByteSwap::Swapped(t)
#define AI_SWAP2(p)
#define AI_SWAP4(p)
#define AI_SWAP8(p)
#define AI_SWAP2P(p)
#define AI_SWAP4P(p)
#define AI_SWAP8P(p)
#define BE_NCONST const
#define AI_LSWAP2(p) ByteSwap::Swap2(&(p))
#define AI_LSWAP4(p) ByteSwap::Swap4(&(p))
#define AI_LSWAP8(p) ByteSwap::Swap8(&(p))
#define AI_LSWAP2P(p) ByteSwap::Swap2((p))
#define AI_LSWAP4P(p) ByteSwap::Swap4((p))
#define AI_LSWAP8P(p) ByteSwap::Swap8((p))
#define LE_NCONST
#endif

namespace Intern {

// --------------------------------------------------------------------------------------------
template <typename T, bool doit>
struct ByteSwapper {
	void operator()(T *inout) {
		ByteSwap::Swap(inout);
	}
};

template <typename T>
struct ByteSwapper<T, false> {
	void operator()(T *) {
	}
};

// --------------------------------------------------------------------------------------------
template <bool SwapEndianess, typename T, bool RuntimeSwitch>
struct Getter {
	void operator()(T *inout, bool le) {
		le = !le;
		if (le) {
			ByteSwapper<T, (sizeof(T) > 1 ? true : false)>()(inout);
		} else {
			ByteSwapper<T, false>()(inout);
		}
	}
};

template <bool SwapEndianess, typename T>
struct Getter<SwapEndianess, T, false> {
	void operator()(T *inout, bool /*le*/) {
		// static branch
		ByteSwapper<T, (SwapEndianess && sizeof(T) > 1)>()(inout);
	}
};
} // namespace Intern
} // namespace FBXDocParser

#endif // BYTESWAPPER_H