libcapsclient/libs/gempa/caps/endianess.h

/***************************************************************************
 * Copyright (C) 2009 by gempa GmbH                                        *
 *                                                                         *
 * All Rights Reserved.                                                    *
 *                                                                         *
 * NOTICE: All information contained herein is, and remains                *
 * the property of gempa GmbH and its suppliers, if any. The intellectual  *
 * and technical concepts contained herein are proprietary to gempa GmbH   *
 * and its suppliers.                                                      *
 * Dissemination of this information or reproduction of this material      *
 * is strictly forbidden unless prior written permission is obtained       *
 * from gempa GmbH.                                                        *
 ***************************************************************************/


#ifndef GEMPA_CAPS_ENDIANESS_H
#define GEMPA_CAPS_ENDIANESS_H

#include <iostream>
#include <stdint.h>
#include <streambuf>


namespace Gempa {
namespace CAPS {
namespace Endianess {

template <typename T1, typename T2> inline const T1* lvalue(const T2 &value) {
	return reinterpret_cast<const T1*>(&value);
}

template <typename T, int swap, int size>
struct Swapper {
	static T Take(const T &v) {
		return v;
	}

	static void Take(T *ar, int len) {}
};


template <typename T>
struct Swapper<T,1,2> {
	static T Take(const T &v) {
		return *lvalue<T, uint16_t>((*reinterpret_cast<const uint16_t*>(&v) >> 0x08) |
		       (*reinterpret_cast<const uint16_t*>(&v) << 0x08));
	}

	static void Take(T *ar, int len) {
		for ( int i = 0; i < len; ++i )
			ar[i] = Take(ar[i]);
	}
};


template <typename T>
struct Swapper<T,1,4> {
	static T Take(const T &v) {
		return *lvalue<T, uint32_t>(((*reinterpret_cast<const uint32_t*>(&v) << 24) & 0xFF000000) |
		       ((*reinterpret_cast<const uint32_t*>(&v) << 8)  & 0x00FF0000) |
		       ((*reinterpret_cast<const uint32_t*>(&v) >> 8)  & 0x0000FF00) |
		       ((*reinterpret_cast<const uint32_t*>(&v) >> 24) & 0x000000FF));
	}

	static void Take(T *ar, int len) {
		for ( int i = 0; i < len; ++i )
			ar[i] = Take(ar[i]);
	}
};


template <typename T>
struct Swapper<T,1,8> {
	static T Take(const T &v) {
		return *lvalue<T, uint64_t>(((*reinterpret_cast<const uint64_t*>(&v) << 56) & 0xFF00000000000000LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) << 40) & 0x00FF000000000000LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) << 24) & 0x0000FF0000000000LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) << 8)  & 0x000000FF00000000LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) >> 8)  & 0x00000000FF000000LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) >> 24) & 0x0000000000FF0000LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) >> 40) & 0x000000000000FF00LL) |
		       ((*reinterpret_cast<const uint64_t*>(&v) >> 56) & 0x00000000000000FFLL));
	}

	static void Take(T *ar, int len) {
		for ( int i = 0; i < len; ++i )
			ar[i] = Take(ar[i]);
	}
};


template <int size>
struct TypeMap {
	typedef void ValueType;
};


template <>
struct TypeMap<1> {
	typedef uint8_t ValueType;
};


template <>
struct TypeMap<2> {
	typedef uint16_t ValueType;
};


template <>
struct TypeMap<4> {
	typedef uint32_t ValueType;
};


template <>
struct TypeMap<8> {
	typedef uint64_t ValueType;
};


template <int swap, int size>
struct ByteSwapper {
	static void Take(void *ar, int len) {}
};


template <int size>
struct ByteSwapper<1,size> {
	static void Take(void *ar, int len) {
		typedef typename TypeMap<size>::ValueType T;
		Swapper<T,1,size>::Take(reinterpret_cast<T*>(ar), len);
	}
};


struct Current {
	enum {
		LittleEndian = ((0x1234 >> 8) == 0x12?1:0),
		BigEndian = 1-LittleEndian
	};
};


struct Converter {
	template <typename T>
	static T ToLittleEndian(const T &v) {
		return Swapper<T,Current::BigEndian,sizeof(T)>::Take(v);
	}

	template <typename T>
	static void ToLittleEndian(T *data, int len) {
		Swapper<T,Current::BigEndian,sizeof(T)>::Take(data, len);
	}

	template <typename T>
	static T FromLittleEndian(const T &v) {
		return Swapper<T,Current::BigEndian,sizeof(T)>::Take(v);
	}

	template <typename T>
	static T ToBigEndian(const T &v) {
		return Swapper<T,Current::LittleEndian,sizeof(T)>::Take(v);
	}

	template <typename T>
	static T FromBigEndian(const T &v) {
		return Swapper<T,Current::LittleEndian,sizeof(T)>::Take(v);
	}
};

struct Reader {
	Reader(std::streambuf &input) : stream(input), good(true) {}

	void operator()(void *data, int size) {
		good = stream.sgetn((char*)data, size) == size;
	}

	template <typename T>
	void operator()(T &v) {
		good = stream.sgetn((char*)&v, sizeof(T)) == sizeof(T);
		v = Converter::FromLittleEndian(v);
	}

	std::streambuf &stream;
	bool good;
};

struct Writer {
	Writer(std::streambuf &output) : stream(output), good(true) {}

	bool operator()(const void *data, int size) {
		return (good = stream.sputn((char*)data, size) == size);
	}

	template <typename T>
	bool operator()(T &v) {
		T tmp = Converter::ToLittleEndian(v);
		return (good = stream.sputn((char*)&tmp, sizeof(T)) == sizeof(T));
	}

	std::streambuf &stream;
	bool good;
};

}
}
}

#endif