From 5519679dcd3e76c7f762a47628503dc4adb87db7 Mon Sep 17 00:00:00 2001
From: Marc Nieper-Wisskirchen <marc@nieper-wisskirchen.de>
Date: Thu, 8 Nov 2018 16:16:07 +0100
Subject: [PATCH] Display zeros in bytevectors as '0'

---
 sexp.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sexp.c b/sexp.c
index 21b705a8..a74163c7 100644
--- a/sexp.c
+++ b/sexp.c
@@ -2069,8 +2069,12 @@ sexp sexp_write_one (sexp ctx, sexp obj, sexp out) {
       for (i=0; i<(sexp_sint_t)len; i++) {
         if (i!=0) sexp_write_char(ctx, ' ', out);
 #if SEXP_BYTEVECTOR_HEX_LITERALS
-	sprintf(buf, "#x%02hhX", ((unsigned char*) str)[i]);
-	sexp_write_string(ctx, buf, out);
+	if (str[i]) {
+	  sprintf(buf, "#x%02hhX", ((unsigned char*) str)[i]);
+	  sexp_write_string(ctx, buf, out);
+	} else {
+	  sexp_write_char (ctx, '0', out);
+	}
 #else
         sexp_write(ctx, sexp_make_fixnum(((unsigned char*)str)[i]), out);
 #endif