// makeconfig.cpp
#include <iostream>
#include <cstdlib>
#include <cstddef>
#include <climits>
#include <cstring>
#include <sstream>

#if CHAR_BIT != 8
  #error "I need my 8-bit chars!"
#endif

#if UINT_MAX == 0xFFFFFFFF
  typedef unsigned long u32;
  static const char thirtytwo[] = "int";
#elif USHRT_MAX = 0xFFFFFFFF
  typedef unsigned short u32;
  static const char thirtytwo[] = "short int";
#elif ULONG_MAX = 0xFFFFFFFF
  typedef unsigned long 32;
  static const char thirtytwo[] = "long int";
#else
  #error "I need my 32-bit integers!"
#endif

#if ~0 != -1
  #error "I need two's complement!"
#endif

static inline u32 fromLittleEndian(const unsigned char* data)
{
  return u32(data[0])
  |     (u32(data[1]) << 8)
  |     (u32(data[2]) << 16)
  |     (u32(data[3]) << 24);
}

int main()
{
  std::stringstream cfg;
  cfg <<
    "#ifndef CONFIG_HPP_INCLUDED\n"
    "#define CONFIG_HPP_INCLUDED\n"
    "\n"
    "typedef unsigned " << thirtytwo << " u32;\n"
    "typedef signed   " << thirtytwo << " s32;\n"
    "\n";
  u32 word  = 0x44332211;
  unsigned char bytes[sizeof(u32)];
  std::memcpy(bytes,&word,sizeof bytes);
  u32 word2 = fromLittleEndian(bytes);
  switch (word2) {
    case 0x44332211:
      cfg << "#define LITTLE_ENDIAN 1\n";
      break;
    case 0x11223344:
      cfg << "#define BIG_ENDIAN 1\n";
      break;
    default:
      std::cerr << "Weird mixed endian machine?!\n";
      return EXIT_FAILURE;
  }
  cfg << "\n#endif\n";
  std::cout << cfg.str();
}

#ifndef CONFIG_HPP_INCLUDED
#define CONFIG_HPP_INCLUDED

typedef unsigned int u32;
typedef signed   int s32;

#define LITTLE_ENDIAN 1

#endif