vcmi/lib/vcmi_endian.h

/*
 * vcmi_endian.h, part of VCMI engine
 *
 * Authors: listed in file AUTHORS in main folder
 *
 * License: GNU General Public License v2.0 or later
 * Full text of license available in license.txt file, in main folder
 *
 */
#pragma once

//FIXME:library file depends on SDL - make cause troubles
#include <SDL_endian.h>

/* Reading values from memory.  
 *
 * read_le_u16, read_le_u32 : read a little endian value from
 *    memory. On big endian machines, the value will be byteswapped.
 */

#if (defined(linux) || defined(__linux) || defined(__linux__)) && (defined(sparc) || defined(__arm__))
/* SPARC does not support unaligned memory access. Let gcc know when
 * to emit the right code. */
struct unaligned_Uint16 { ui16 val __attribute__(( packed )); };
struct unaligned_Uint32 { ui32 val __attribute__(( packed )); };

static inline ui16 read_unaligned_u16(const void *p)
{
	const struct unaligned_Uint16 *v = reinterpret_cast<const struct unaligned_Uint16 *>(p);
	return v->val;
}

static inline ui32 read_unaligned_u32(const void *p)
{
	const struct unaligned_Uint32 *v = reinterpret_cast<const struct unaligned_Uint32 *>(p);
	return v->val;
}

#define read_le_u16(p) (SDL_SwapLE16(read_unaligned_u16(p)))
#define read_le_u32(p) (SDL_SwapLE32(read_unaligned_u32(p)))

#define PACKED_STRUCT __attribute__(( packed ))

#else

#define read_le_u16(p) (SDL_SwapLE16(* reinterpret_cast<const ui16 *>(p)))
#define read_le_u32(p) (SDL_SwapLE32(* reinterpret_cast<const ui32 *>(p)))

#define PACKED_STRUCT

#endif

static inline char readChar(const ui8 * buffer, int & i)
{
    return buffer[i++];
}

static inline std::string readString(const ui8 * buffer, int & i)
{
    int len = read_le_u32(buffer + i);
    i += 4;
	assert(len >= 0 && len <= 500000); //not too long
    std::string ret;
    ret.reserve(len);
    for(int gg = 0; gg < len; ++gg)
	{
        ret += buffer[i++];
	}
	return ret;
}