replace ec3_reader and ec3_writer with a unified image and tag io interface

src/misc.c

@@ -12,8 +12,6 @@ static enum ec3_status identifier_from_int_string(
 	uint64_t *out,
 	int base)
 {
-	/* skip leading '0x' */
-	s += 2;
 	char *ep = NULL;
 	uint64_t v = strtoull(s, &ep, base);
 
@@ -39,7 +37,7 @@ static bool is_base10_string(const char *s)
 enum ec3_status ec3_identifier_from_string(const char *s, uint64_t *out)
 {
 	if (s[0] == '0' && s[1] == 'x') {
-		return identifier_from_int_string(s, out, 16);
+		return identifier_from_int_string(s + 2, out, 16);
 	}
 
 	if (is_base10_string(s)) {