#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>

#ifndef S_ISREG
#ifndef S_IFREG
#define S_IFREG _S_IFREG
#endif
#ifndef S_IFMT
#define S_IFMT _S_IFMT
#endif
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#endif /* not S_ISREG */

#ifndef O_BINARY
#ifdef _O_BINARY
#define O_BINARY _O_BINARY
#else
#define O_BINARY 0
#endif
#endif

int filemap(const char *name,
	    void (*processor)(const void *, size_t, const char *, void *arg),
	    void *arg)
{
  size_t nbytes;
  int fd;
  int n;
  struct stat sb;
  void *p;

  fd = open(name, O_RDONLY|O_BINARY);
  if (fd < 0) {
    perror(name);
    return 0;
  }
  if (fstat(fd, &sb) < 0) {
    perror(name);
    return 0;
  }
  if (!S_ISREG(sb.st_mode)) {
    fprintf(stderr, "%s: not a regular file\n", name);
    return 0;
  }
  nbytes = sb.st_size;
  p = malloc(nbytes);
  if (!p) {
    fprintf(stderr, "%s: out of memory\n", name);
    return 0;
  }
  n = read(fd, p, nbytes);
  if (n < 0) {
    perror(name);
    close(fd);
    return 0;
  }
  if (n != nbytes) {
    fprintf(stderr, "%s: read unexpected number of bytes\n", name);
    close(fd);
    return 0;
  }
  processor(p, nbytes, name, arg);
  free(p);
  close(fd);
  return 1;
}