Added bacnet_strnlen and bacnet_stricmp to avoid libc compiler problems (#857)

* Added bacnet_strnlen and bacnet_stricmp to avoid libc compiler problems

* FIxed compiler warnings in printf conversions.

src/bacnet/bacstr.c

@@ -393,31 +393,6 @@ bool characterstring_init(
     return status;
 }
 
-/**
- * @brief Return the length of a string, within a maximum length
- * @note The strnlen function is non-standard and not available in
- * all libc implementations.  This function is a workaround for that.
- * @details The strnlen function computes the smaller of the number
- * of characters in the array pointed to by s, not including any
- * terminating null character, or the value of the maxlen argument.
- * The strnlen function examines no more than maxlen bytes of the
- * array pointed to by s.
- * @param s - string to check
- * @param maxlen - maximum length to check
- * @return The strnlen function returns the number of bytes that
- * precede the first null character in the array pointed to by s,
- * if s contains a null character within the first maxlen characters;
- * otherwise, it returns maxlen.
- */
-size_t characterstring_strnlen(const char *str, size_t maxlen)
-{
-    const char *p = memchr(str, 0, maxlen);
-    if (p == NULL) {
-        return maxlen;
-    }
-    return (p - str);
-}
-
 /**
  * Initialize a BACnet character string.
  * Returns false if the string exceeds capacity.
@@ -434,7 +409,7 @@ bool characterstring_init_ansi_safe(
 {
     return characterstring_init(
         char_string, CHARACTER_ANSI_X34, value,
-        value ? characterstring_strnlen(value, tmax) : 0);
+        value ? bacnet_strnlen(value, tmax) : 0);
 }
 
 /**
@@ -1246,3 +1221,51 @@ bool octetstring_value_same(
     return false;
 }
 #endif
+
+/**
+ * @brief Compare two strings, case insensitive
+ * @param a - first string
+ * @param b - second string
+ * @return 0 if the strings are equal, non-zero if not
+ * @note The stricmp() function is not included C standard.
+ */
+int bacnet_stricmp(const char *a, const char *b)
+{
+    int twin_a, twin_b;
+
+    do {
+        twin_a = *(const unsigned char *)a;
+        twin_b = *(const unsigned char *)b;
+        twin_a = tolower(toupper(twin_a));
+        twin_b = tolower(toupper(twin_b));
+        a++;
+        b++;
+    } while ((twin_a == twin_b) && (twin_a != '\0'));
+
+    return twin_a - twin_b;
+}
+
+/**
+ * @brief Return the length of a string, within a maximum length
+ * @note The strnlen function is non-standard and not available in
+ * all libc implementations.  This function is a workaround for that.
+ * @details The strnlen function computes the smaller of the number
+ * of characters in the array pointed to by s, not including any
+ * terminating null character, or the value of the maxlen argument.
+ * The strnlen function examines no more than maxlen bytes of the
+ * array pointed to by s.
+ * @param s - string to check
+ * @param maxlen - maximum length to check
+ * @return The strnlen function returns the number of bytes that
+ * precede the first null character in the array pointed to by s,
+ * if s contains a null character within the first maxlen characters;
+ * otherwise, it returns maxlen.
+ */
+size_t bacnet_strnlen(const char *str, size_t maxlen)
+{
+    const char *p = memchr(str, 0, maxlen);
+    if (p == NULL) {
+        return maxlen;
+    }
+    return (p - str);
+}