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

struct {
  char head[6];
  long len;
} header;

int main(int argc, char *argv[]) {
  int fd;
  long len;
  struct stat s;
  void *p = 0;
  char outfile[100], *data;

  if (argc < 2) return 1;

  if ((fd = open(argv[1], O_RDONLY)) < 0) {
    fprintf(stderr, "%s: %s: %s\n", argv[0], argv[1], strerror(errno));
    return 1;
  }

  fstat(fd, &s);

  if ((p = mmap(0, s.st_size, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
    fprintf(stderr, "%s: %s: %s\n", argv[0], argv[1], strerror(errno));
    return 1;
  }

  data = malloc(s.st_size);
  sprintf(outfile, "%s.z", argv[1]);
  compress(data, &len, p, s.st_size);
  munmap(p, s.st_size);
  close(fd);

  fd = open(outfile, O_WRONLY | O_CREAT, 00644);
  write(fd, "sZIP01", 6);
  write(fd, &s.st_size, 4);
  write(fd, data, len);
  close(fd);

  return 0;
}