Fix rtrim_pos to return an exclusive end pointer

Author: dpw13

include/utils/strings.h

@@ -6,6 +6,7 @@
 #include <ctype.h>
 #include <stdlib.h>
 #include <stdbool.h>
+#include <string.h>
 
 /**
  * Safe string duplication
@@ -83,7 +84,9 @@ static inline const char *ltrim_pos(const char *input) {
 }
 
 /**
- * Returns a pointer to the last printable character in the input string.
+ * Returns a pointer to the byte _after_ the last printable character
+ * in the input string. Set the returned pointer to '\0' to terminate
+ * the string after the last printable character.
  */
 static inline const char *rtrim_pos(const char *input, size_t input_size) {
     if (!input) {
@@ -100,7 +103,8 @@ static inline const char *rtrim_pos(const char *input, size_t input_size) {
     while (end > input && !isgraph((unsigned char)*end)) {
         end--;
     }
-    return end;
+    // Point to the character after the last printable character.
+    return end + 1;
 }
 
 #endif //STRINGS_H

src/utils/strings.c

@@ -1,5 +1,3 @@
-#include <string.h>
-
 #include "utils/strings.h"
 #include "core/logger.h"