diff --git a/tools/aapt/Resource.cpp b/tools/aapt/Resource.cpp
index 6ebf41f1..cc9207d 100644
--- a/tools/aapt/Resource.cpp
+++ b/tools/aapt/Resource.cpp
@@ -553,7 +553,7 @@
                     String8(parser.getElementName(&len)).string(), attr);
             return ATTR_LEADING_SPACES;
         }
-        if (str[len-1] == ' ') {
+        if (len != 0 && str[len-1] == ' ') {
             fprintf(stderr, "%s:%d: Tag <%s> attribute %s can not end with a space.\n",
                     path.string(), parser.getLineNumber(),
                     String8(parser.getElementName(&len)).string(), attr);