Fixed == operator for empty string comparison.

ZString.cpp

@@ -68,6 +68,8 @@ namespace coreutils {
    }
 
    bool ZString::operator==(const ZString &valuex) {
+      if((valuex.getLength() == 0) && (length != 0))
+	return false;
       return (strncmp(data, valuex.data, valuex.length <= length ? valuex.length : length) == 0);
    }
 
@@ -348,11 +350,11 @@ namespace coreutils {
       return ZString(temp, size);
    }
    
-   char *ZString::getData() {
+   char *ZString::getData() const {
       return data;
    }
    
-   char *ZString::getCursor() {
+   char *ZString::getCursor() const {
       return cursor;
    }
 
@@ -362,7 +364,7 @@ namespace coreutils {
       this->cursor = cursor;
    }
    
-   size_t ZString::getLength() {
+   size_t ZString::getLength() const {
       return length - (cursor - data);
    }