Merge pull request #222 from rwalker-apple/Be-careful-with-snprintf

Be careful with snprintf

Author: woody-apple

src/lib/support/ErrorStr.cpp

@@ -133,20 +133,23 @@ DLL_EXPORT void FormatError(char * buf, uint16_t bufSize, const char * subsys, i
 
 #else // CHIP_CONFIG_SHORT_ERROR_STR
 
-    int len = 0;
+    const char * subsysSep = " ";
+    const char * descSep   = ": ";
 
-    if (subsys != NULL)
+    if (subsys == NULL)
     {
-        len = snprintf(buf, bufSize, "%s ", subsys);
+        subsys    = "";
+        subsysSep = "";
     }
-
-    len += snprintf(buf + len, bufSize - len, "Error %" PRId32 " (0x%08" PRIX32 ")", err, (uint32_t) err);
-
-    if (desc != NULL)
+    if (desc == NULL)
     {
-        (void) snprintf(buf + len, bufSize - len, ": %s", desc);
+        desc    = "";
+        descSep = "";
     }
 
+    (void) snprintf(buf, bufSize, "%s%sError %" PRId32 " (0x%08" PRIX32 ")%s%s", subsys, subsysSep, err, (uint32_t) err, descSep,
+                    desc);
+
 #endif // CHIP_CONFIG_SHORT_ERROR_STR
 }