test-sha1: add a binary output mode

The test-sha1 helper program will run our internal sha1
routines over its input and output the 40-byte hex sha1.
Sometimes, however, it is useful to have the binary 20-byte
sha1 (and it's a pain to convert back in the shell). Let's
add a "-b" option to output the binary version.

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-sha1.c

@@ -5,10 +5,15 @@ int main(int ac, char **av)
 	git_SHA_CTX ctx;
 	unsigned char sha1[20];
 	unsigned bufsz = 8192;
+	int binary = 0;
 	char *buffer;
 
-	if (ac == 2)
-		bufsz = strtoul(av[1], NULL, 10) * 1024 * 1024;
+	if (ac == 2) {
+		if (!strcmp(av[1], "-b"))
+			binary = 1;
+		else
+			bufsz = strtoul(av[1], NULL, 10) * 1024 * 1024;
+	}
 
 	if (!bufsz)
 		bufsz = 8192;
@@ -42,6 +47,10 @@ int main(int ac, char **av)
 		git_SHA1_Update(&ctx, buffer, this_sz);
 	}
 	git_SHA1_Final(sha1, &ctx);
-	puts(sha1_to_hex(sha1));
+
+	if (binary)
+		fwrite(sha1, 1, 20, stdout);
+	else
+		puts(sha1_to_hex(sha1));
 	exit(0);
 }