diff --git a/stim/envi/agilent_binary.h b/stim/envi/agilent_binary.h
index 14aa524..b103e68 100644
--- a/stim/envi/agilent_binary.h
+++ b/stim/envi/agilent_binary.h
@@ -37,9 +37,10 @@ public:
 		return size() * sizeof(T);
 	}
 	void alloc(){
+		if (ptr != NULL) free(ptr);
 		ptr = (T*) malloc(bytes());
 	}
-	void alloc(size_t x, size_t y, size_t z){
+	void alloc(size_t x, size_t y, size_t z){		
 		R[0] = x;
 		R[1] = y;
 		R[2] = z;
--
libgit2 0.21.4