#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/file.h>

#include <md5.h>

#define NEVER (-1)
#define MAYBE 0
#define ALWAYS 1
#define COMPAT 2

static int print_names = MAYBE;

extern const char *__progname;

static void process_file(int fd, void (*pfn)(void *, const void *), void *parg, const char *fn)
{
 void *md5;
 int n;
 static char buf[65536];

 md5 = md5_init();
 while (1)
  { n = read(fd,&buf[0],sizeof(buf));
    if (n < 0)
     { fprintf(stderr,"%s: read error on %s: %s\n",__progname,fn,strerror(errno));
       n = 0;
     }
    if (n == 0)
     { md5_result(md5,&buf[0]);
       (*pfn)(parg,&buf[0]);
       return;
     }
    md5_process_bytes(md5,&buf[0],n);
  }
}

static void scan_args(int *acp, char ***avp)
{
 int errs;
 int ac;
 char **av;
 int i;
 int j;

 errs = 0;
 ac = *acp;
 av = *avp;
 j = 1;
 for (i=1;i<ac;i++)
  { if (av[i][0] == '-')
     { if (!strcmp(av[i],"-h"))
	{ print_names = NEVER;
	}
       else if (!strcmp(av[i],"-H"))
	{ print_names = ALWAYS;
	}
       else if (!strcmp(av[i],"-c"))
	{ print_names = COMPAT;
	}
       else
	{ fprintf(stderr,"%s: unknown flag %s\n",__progname,av[i]);
	  errs ++;
	}
     }
    else
     { if (j != i) av[j] = av[i];
       j ++;
     }
  }
 if (errs) exit(1);
 av[j] = 0;
 *acp = j;
}

static void print_sum_stdin(void *arg __attribute__((__unused__)), const void *sum)
{
 int n;

 for (n=0;n<16;n++) printf("%02x",((const unsigned char *)sum)[n]);
 if (print_names == ALWAYS) printf(" stdin");
 printf("\n");
}

static void print_sum_file(void *arg, const void *sum)
{
 int n;

 if (print_names == COMPAT) printf("MD5 (%s) = ",(const char *)arg);
 for (n=0;n<16;n++) printf("%02x",((const unsigned char *)sum)[n]);
 if (print_names == ALWAYS) printf(" %s",(const char *)arg);
 printf("\n");
}

int main(int, char **);
int main(int ac, char **av)
{
 scan_args(&ac,&av);
 if (print_names == MAYBE) print_names = (ac < 3) ? NEVER : ALWAYS;
 if (ac == 1)
  { process_file(0,print_sum_stdin,0,"standard input");
    exit(0);
  }
 else
  { int i;
    int fd;
    int nerr;
    nerr = 0;
    for (i=1;i<ac;i++)
     { fd = open(av[i],O_RDONLY,0);
       if (fd < 0)
	{ fprintf(stderr,"%s: can't open %s: %s\n",__progname,av[i],strerror(errno));
	  nerr ++;
	}
       else
	{ process_file(fd,print_sum_file,av[i],av[i]);
	  close(fd);
	}
     }
    exit(nerr);
  }
}