From 9f7a824206702350427aa59382082d1019c3011d Mon Sep 17 00:00:00 2001
From: Mark H Weaver <mhw@netris.org>
Date: Tue, 18 Jun 2019 02:09:16 -0400
Subject: [PATCH] scm_mkstrport: Optimize the POS -> BYTE_POS conversion.

* libguile/strports.c (scm_mkstrport): Use 'scm_c_string_utf8_length' to
avoid the conversion to UTF-8.
---
 libguile/strports.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libguile/strports.c b/libguile/strports.c
index 876a62a86..14cdfa06b 100644
--- a/libguile/strports.c
+++ b/libguile/strports.c
@@ -195,8 +195,8 @@ scm_mkstrport (SCM pos, SCM str, long modes, const char *caller)
       else
         /* Inefficient but simple way to convert the character position
            POS into a byte position BYTE_POS.  */
-        free (scm_to_utf8_stringn (scm_substring (str, SCM_INUM0, pos),
-                                   &byte_pos));
+        byte_pos = scm_c_string_utf8_length
+          (scm_substring (str, SCM_INUM0, pos));
     }
 
   stream = scm_gc_typed_calloc (struct string_port);