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

#define NEVER 1
#define MAYBE 2
#define ALWAYS 3
#define COMPAT 4
static int print_names = MAYBE;
static int size = -1;

extern const char *__progname;

static const char *algname(int size)
{
 switch (size)
  { case 0:   return("SHA");    break;
    case 1:   return("SHA1");   break;
    case 224: return("SHA224"); break;
    case 256: return("SHA256"); break;
    case 384: return("SHA384"); break;
    case 512: return("SHA512"); break;
  }
 abort();
}

static void process_file(
	int fd,
	int pnames,
	const char *fn_out,
	const char *fn_err)
{
 void *h;
 int n;
 int l;
 static char buf[65536];

 h = shaX_init(size);
 while (1)
  { n = read(fd,&buf[0],sizeof(buf));
    if (n < 0)
     { fprintf(stderr,"%s: read error on %s: %s\n",__progname,fn_err,strerror(errno));
       n = 0;
     }
    if (n == 0)
     { l = shaX_hashsize(h);
       shaX_result(h,&buf[0]);
       if (pnames == COMPAT) printf("%s (%s) = ",algname(size),fn_out);
       for (n=0;n<l;n++) printf("%02x",((unsigned char *)&buf[0])[n]);
       if (pnames == ALWAYS) printf(" %s",fn_out);
       printf("\n");
       return;
     }
    shaX_process_bytes(h,&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") || !strcmp(av[i],"-no-names"))
	{ print_names = NEVER;
	}
       else if (!strcmp(av[i],"-H") || !strcmp(av[i],"-names"))
	{ print_names = ALWAYS;
	}
       else if (!strcmp(av[i],"-c"))
	{ print_names = COMPAT;
	}
       else if (!strcmp(av[i],"-sha"))
	{ size = 0;
	}
       else if (!strcmp(av[i],"-sha1"))
	{ size = 1;
	}
       else if (!strcmp(av[i],"-sha256"))
	{ size = 256;
	}
       else if (!strcmp(av[i],"-sha384"))
	{ size = 384;
	}
       else if (!strcmp(av[i],"-sha512"))
	{ size = 512;
	}
       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 set_default_alg(const char *name)
{
 const char *slash;
 const char *bn;

 slash = rindex(name,'/');
 bn = slash ? slash+1 : name;
      if (!strcmp(bn,"sha")) size = 0;
 else if (!strcmp(bn,"sha1")) size = 1;
 else if (!strcmp(bn,"sha256")) size = 256;
 else if (!strcmp(bn,"sha384")) size = 384;
 else if (!strcmp(bn,"sha512")) size = 512;
}

int main(int, char **);
int main(int ac, char **av)
{
 set_default_alg(av[0]);
 scan_args(&ac,&av);
 if (size < 0)
  { fprintf(stderr,"%s: must specify one of the -sha* flags\n",__progname);
    exit(1);
  }
 if (print_names == MAYBE) print_names = (ac < 3) ? NEVER : ALWAYS;
 if (ac == 1)
  { process_file(0,print_names,"stdin","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_names,av[i],av[i]);
	  close(fd);
	}
     }
    exit(nerr);
  }
}