#include <stdlib.h>
#include <stdio.h>
#include <windows.h>

#define CYGPROPS_RES_NAME "cygprops"

#define CYGPROPS_STRUCT_VERSION 0x00000001
typedef struct _cygprops {
  unsigned short allow_multiple;
  unsigned short something_else;
  unsigned short extra_sz; /* size of byte array, below */
  unsigned char *extra;    /* must be even; extend to extra_sz+1 if needed */
} cygprops_t;

cygprops_t cygprops = { 0, 0, 0, NULL };

void * readres_ushort(void *addr, unsigned short *val)
{
  unsigned short * p = (unsigned short *) addr;
  *val = *p++;
  return (void *) p;
}
void * readres_uchars_bswap(void *addr, unsigned int cnt, unsigned char *val)
{
  unsigned char * p = (unsigned char *) addr;
  unsigned char a,b;
  int i;
  for (i = 0; i < cnt; )
    {
      a = *p++;
      b = *p++;
      i += 2;
      *val++ = b;
      *val++ = a;
    }
  return (void *) p;
}

void load_props(void)
{
  int i;
  LPVOID lpcygprops;
  unsigned short cygprops_version;

  // Load toolbar resource.
  HMODULE hMod = GetModuleHandle(NULL);
  HGLOBAL hglb = LoadResource(hMod, FindResource(hMod, CYGPROPS_RES_NAME, RT_RCDATA));
  lpcygprops = LockResource(hglb);
  lpcygprops = readres_ushort(lpcygprops, &cygprops_version);
  if (cygprops_version != CYGPROPS_STRUCT_VERSION)
    {
      fprintf(stderr, "bad cygprops version; expected %d got %d\n",
              CYGPROPS_STRUCT_VERSION, cygprops_version);
      exit (1);
    }

  lpcygprops = readres_ushort(lpcygprops, &cygprops.allow_multiple);
  lpcygprops = readres_ushort(lpcygprops, &cygprops.something_else);
  lpcygprops = readres_ushort(lpcygprops, &cygprops.extra_sz);
  cygprops.extra = (unsigned char *) malloc (cygprops.extra_sz & 0x01
                                             ? cygprops.extra_sz + 1
                                             : cygprops.extra_sz);
  lpcygprops = readres_uchars_bswap(lpcygprops, cygprops.extra_sz, cygprops.extra);

  UnlockResource (hglb);
  FreeResource (hglb);
}
void destroy_props(void)
{
  if (cygprops.extra)
    {
      free(cygprops.extra);
      cygprops.extra = NULL;
    }
}
void print_cygprops(void)
{
  int i;
  unsigned char *p;
  printf("allow_multiple: 0x%04x\n", cygprops.allow_multiple);
  printf("something_else: 0x%04x\n", cygprops.something_else);
  printf("extra_sz      : 0x%04x\n", cygprops.extra_sz);
  printf("extra         :");
  if (cygprops.extra)
    {
      for (i = 0, p = cygprops.extra; i < cygprops.extra_sz; i++)
          printf(" 0x%02x", *p++);
      printf("\n");
    }
  else
    printf(" <NULL>\n");
}

int main(int argc, char *argv[])
{
  printf("BEFORE: \n");
  print_cygprops();
  printf("AFTER: \n");
  load_props();
  print_cygprops();
  destroy_props();
  return 0;
}