From 563c32593f78948a3419a2cfe5c1deffd4bc80c0 Mon Sep 17 00:00:00 2001
From: tsteven4 <13596209+tsteven4@users.noreply.github.com>
Date: Sat, 20 Jul 2024 11:35:52 -0600
Subject: [PATCH] fix gpsapp copy_char_array that could leave part of a packet
 uninitialized. (#1301)

* fix gpsapp copy_char_array that could leave part of a packet uninitialized.

* tidy up a bit.

* delete empty statement
---
 jeeps/gpsapp.cc | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/jeeps/gpsapp.cc b/jeeps/gpsapp.cc
index 4b1441ed8..d56a603e1 100644
--- a/jeeps/gpsapp.cc
+++ b/jeeps/gpsapp.cc
@@ -125,28 +125,31 @@ char	gps_save_string[GPS_ARB_LEN];
  * we uppercase the string because some models (III's and 12's) react
  * violently to lower case data.
  */
-typedef enum { UpperNo = 0, UpperYes = 1 } copycase;
+enum copycase { UpperNo, UpperYes };
 
 static
-void copy_char_array(UC** dst, char* src, int count, copycase mustupper)
+void copy_char_array(UC** dst, const char* src, int count, copycase mustupper)
 {
   UC* d = *dst;
-  int ocount =  count;
-  do {
+  int copied = 0;
+  // Copy up to count characters from the source to the desitnation.
+  for (int i = 0; i < count; ++i) {
     UC sc = *src++;
     if (sc == 0) {
-      while (count--) {
-        *d++ = ' ';
-      }
       break;
     }
     if (!isalnum(sc)) {
       continue;
-    } else {
-      *d++ = mustupper == UpperYes ? toupper(sc) : sc;
     }
-  } while (--count) ;
-  *dst += ocount;
+    *d++ = mustupper == UpperYes ? toupper(sc) : sc;
+    copied++;
+  }
+  // If necessary pad with space characters so that the total count
+  // of characters written to the destination is count.
+  for (int i = copied; i < count; ++i) {
+    *d++ = ' ';
+  }
+  *dst += count;
 }
 
 
-- 
2.30.2