Add crypt.[ch] and update md5sum and sha1sum

Factor out the code from md5sum and sha1sum into a util function.

Use FILE * instead of a file descriptor.  This will make it a bit
easier/more consistent when we implement support for the -c option.

sha1sum.c

@@ -1,15 +1,18 @@
 /* See LICENSE file for copyright and license details. */
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include "util.h"
+#include "crypt.h"
 #include "sha1.h"
 
-static void sha1sum(int fd, const char *f);
+struct sha1 s;
+struct crypt_ops sha1_ops = {
+	sha1_init,
+	sha1_update,
+	sha1_sum,
+	&s,
+};
 
 static void
 usage(void)
@@ -20,7 +23,8 @@ usage(void)
 int
 main(int argc, char *argv[])
 {
-	int fd;
+	FILE *fp;
+	uint8_t md[SHA1_DIGEST_LENGTH];
 
 	ARGBEGIN {
 	default:
@@ -28,40 +32,18 @@ main(int argc, char *argv[])
 	} ARGEND;
 
 	if (argc == 0) {
-		sha1sum(STDIN_FILENO, "<stdin>");
+		cryptsum(&sha1_ops, stdin, "<stdin>", md);
+		mdprint(md, "<stdin>", sizeof(md));
 	} else {
 		for (; argc > 0; argc--) {
-			if ((fd = open(*argv, O_RDONLY)) < 0)
-				eprintf("open %s:", *argv);
-			sha1sum(fd, *argv);
-			close(fd);
+			if ((fp = fopen(*argv, "r")) == NULL)
+				eprintf("fopen %s:", *argv);
+			cryptsum(&sha1_ops, fp, *argv, md);
+			mdprint(md, *argv, sizeof(md));
+			fclose(fp);
 			argv++;
 		}
 	}
 
 	return 0;
 }
-
-static void
-sha1sum(int fd, const char *f)
-{
-	unsigned char buf[BUFSIZ];
-	unsigned char digest[SHA1_DIGEST_LENGTH];
-	struct sha1 s;
-	ssize_t n;
-	int i;
-
-	sha1_init(&s);
-	while ((n = read(fd, buf, sizeof buf)) > 0)
-		sha1_update(&s, buf, n);
-	if (n < 0) {
-		eprintf("%s: read error:", f);
-		return;
-	}
-
-	sha1_sum(&s, digest);
-
-	for (i = 0; i < sizeof(digest); i++)
-		printf("%02x", digest[i]);
-	printf("  %s\n", f);
-}