#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <sys/types.h>
#include <ctype.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <zlib.h>


/*****************************************************************************/
/*                                                                           */
/*              Front ends to various library calls                          */
/*                                                                           */
/*****************************************************************************/


static int syspagesize = 0, pagemask, offmask;

caddr_t femmap(int fd, off_t foff, size_t syz, int prot, u_char *msg) {
  /* femmap() and fem/unmap() take care of the need to allocate 
     on page boundaries and in multiples of pages. */
  off_t pfoff;  /* foff on a page boundary */
  size_t psyz; /* syz rounded up to full pages */
  int chopped;
  caddr_t rslt;
  if (syspagesize == 0) {
    syspagesize = getpagesize();
    offmask = syspagesize - 1;
    pagemask = ~offmask;
    if (0) printf("--- Syspagesize %d, pagemask %X, offmask %X\n", 
		  syspagesize, pagemask, offmask);
  }
  pfoff = foff & pagemask;
  chopped = foff & offmask;
  psyz = (syz + chopped + syspagesize - 1) & pagemask;



  if ((rslt = mmap(0, psyz, prot, MAP_SHARED, 
			  fd, pfoff))  ==MAP_FAILED) {
    fprintf(stderr,"Error: %s\n", msg);
    perror("Mmap");
    exit(201);
  }

  printf("Just Mmaped %d which is now at address %X\n", psyz, (int)rslt);

  if (0)
    printf("   Mapping %d at %X <---> %d (%s\n", psyz, (int)rslt, (int)pfoff, 
	   msg);
  return (rslt + chopped);
}

void femunmap(caddr_t cad, size_t syz, u_char *msg) {
  /* Unmap the specified block of memory.  Cad should be the result
     returned by a call to femmap() and syz should be the size 
     passed to femmap()

  */
  size_t psyz; /* syz rounded up to full pages */
  int chopped;
  caddr_t pcad;

  chopped = (int) cad & offmask;
  pcad = (caddr_t) ((int) cad & pagemask);
  psyz = (syz + chopped + syspagesize - 1) & pagemask;

  printf("About to UnMapp %d at %X\n", psyz, (int)pcad);

  if (munmap(pcad, psyz)) {
    perror(msg);
    exit(205);
  }
  if (0)
    printf(" UnMapping %d at %X - (%s)\n", psyz, (int)pcad, msg);

}

static off_t bnsyz;
static u_char *bnams;

int
main(void)
{
   int tfd;
   u_char filename[100];
   struct stat finfo;

   strcpy(filename, "cygcheck.out");

   tfd = open(filename, O_RDONLY, 0);

   fstat(tfd, &finfo);

   bnsyz = finfo.st_size;

   bnams = femmap(tfd, 0, bnsyz, PROT_READ, "bnams");

   if (bnams != NULL) {
      femunmap(bnams, bnsyz, "bnams");
      bnams = NULL;
   }

   return(0);
}