/*
  A replacement for SDL_endian.h for idlib/Lib.cpp

  (I did some changes to remove dependencies to other SDL headers)
  
  Based on the original SDL_endian.h:

  Simple DirectMedia Layer
  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#ifndef STUB_SDL_ENDIAN_H
#define STUB_SDL_ENDIAN_H

#include <stdint.h>
#include "platform.h"

#define SDL_LIL_ENDIAN  1234
#define SDL_BIG_ENDIAN  4321

#ifndef BUILD_IS_BIG_ENDIAN
  #error BUILD_IS_BIG_ENDIAN should be defined!
#endif

#if BUILD_IS_BIG_ENDIAN // this is from config.h, set by cmake
  #define SDL_BYTEORDER SDL_BIG_ENDIAN
#else
  #define SDL_BYTEORDER SDL_LIL_ENDIAN
#endif

typedef uint16_t Uint16;
typedef uint32_t Uint32;
typedef uint64_t Uint64;

#ifndef SDL_INLINE
#if defined(__GNUC__)
#define SDL_INLINE __inline__
#elif defined(_MSC_VER) || defined(__BORLANDC__) || \
      defined(__DMC__) || defined(__SC__) || \
      defined(__WATCOMC__) || defined(__LCC__) || \
      defined(__DECC) || defined(__CC_ARM)
#define SDL_INLINE __inline
#ifndef __inline__
#define __inline__ __inline
#endif
#else
#define SDL_INLINE inline
#ifndef __inline__
#define __inline__ inline
#endif
#endif
#endif /* SDL_INLINE not defined */

#ifndef SDL_FORCE_INLINE
#if defined(_MSC_VER)
#define SDL_FORCE_INLINE __forceinline
#elif ( (defined(__GNUC__) && (__GNUC__ >= 4)) || defined(__clang__) )
#define SDL_FORCE_INLINE __attribute__((always_inline)) static __inline__
#else
#define SDL_FORCE_INLINE static SDL_INLINE
#endif
#endif /* SDL_FORCE_INLINE not defined */

#define SDL_static_cast(type, val)  (type)(val)

#if defined(__GNUC__) && defined(__i386__) && \
   !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
    int result;

  __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
    return (Uint16)result;
}
#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
    return x;
}
#elif defined(__WATCOMC__) && defined(__386__)
extern _inline Uint16 SDL_Swap16(Uint16);
#pragma aux SDL_Swap16 = \
  "xchg al, ah" \
  parm   [ax]   \
  modify [ax];
#else
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
    return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
}
#endif

#if defined(__GNUC__) && defined(__i386__)
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("bswap %0": "=r"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("bswapl %0": "=r"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
    Uint32 result;

  __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
  __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
  __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
    return result;
}
#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
    return x;
}
#elif defined(__WATCOMC__) && defined(__386__)
extern _inline Uint32 SDL_Swap32(Uint32);
#ifndef __SW_3 /* 486+ */
#pragma aux SDL_Swap32 = \
  "bswap eax"  \
  parm   [eax] \
  modify [eax];
#else  /* 386-only */
#pragma aux SDL_Swap32 = \
  "xchg al, ah"  \
  "ror  eax, 16" \
  "xchg al, ah"  \
  parm   [eax]   \
  modify [eax];
#endif
#else
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
    return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
                                    ((x >> 8) & 0x0000FF00) | (x >> 24)));
}
#endif

#if defined(__GNUC__) && defined(__i386__)
SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)
{
    union
    {
        struct
        {
            Uint32 a, b;
        } s;
        Uint64 u;
    } v;
    v.u = x;
  __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
            "1"(v.s.
                b));
    return v.u;
}
#elif defined(__GNUC__) && defined(__x86_64__)
SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)
{
  __asm__("bswapq %0": "=r"(x):"0"(x));
    return x;
}
#else
SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)
{
    Uint32 hi, lo;

    /* Separate into high and low 32-bit values and swap them */
    lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
    x >>= 32;
    hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
    x = SDL_Swap32(lo);
    x <<= 32;
    x |= SDL_Swap32(hi);
    return (x);
}
#endif


SDL_FORCE_INLINE float
SDL_SwapFloat(float x)
{
    union
    {
        float f;
        Uint32 ui32;
    } swapper;
    swapper.f = x;
    swapper.ui32 = SDL_Swap32(swapper.ui32);
    return swapper.f;
}

#if SDL_BYTEORDER == SDL_LIL_ENDIAN
#define SDL_SwapLE16(X) (X)
#define SDL_SwapLE32(X) (X)
#define SDL_SwapLE64(X) (X)
#define SDL_SwapFloatLE(X)  (X)
#define SDL_SwapBE16(X) SDL_Swap16(X)
#define SDL_SwapBE32(X) SDL_Swap32(X)
#define SDL_SwapBE64(X) SDL_Swap64(X)
#define SDL_SwapFloatBE(X)  SDL_SwapFloat(X)
#else
#define SDL_SwapLE16(X) SDL_Swap16(X)
#define SDL_SwapLE32(X) SDL_Swap32(X)
#define SDL_SwapLE64(X) SDL_Swap64(X)
#define SDL_SwapFloatLE(X)  SDL_SwapFloat(X)
#define SDL_SwapBE16(X) (X)
#define SDL_SwapBE32(X) (X)
#define SDL_SwapBE64(X) (X)
#define SDL_SwapFloatBE(X)  (X)
#endif

#endif // STUB_SDL_ENDIAN_H
