diff --git a/btree.h b/btree.h
index eaf8eb7..206410e 100644
--- a/btree.h
+++ b/btree.h
@@ -1,7 +1,14 @@
 #ifndef BTREE_H
 #define BTREE_H
 
+#include "btypes.h"  // integer definitions
+
 enum treeTypes { BT_CUSTOM, BT_PCHAR, BT_STRING, BT_SINGLE, BT_DOUBLE, BT_INT32, BT_INT64 };
 
+struct TBlockRun {
+  int32  AG;
+  uInt16 start;
+  uInt16 len;
+};
 
 #endif
diff --git a/btypes.h b/btypes.h
new file mode 100644
index 0000000..fe843e5
--- /dev/null
+++ b/btypes.h
@@ -0,0 +1,13 @@
+#ifndef BTYPES_H
+#define BTYPES_H
+
+typedef signed char            int8;
+typedef signed short int       int16;
+typedef signed long int        int32;
+typedef signed long long int   int64;
+typedef unsigned char          uInt8;
+typedef unsigned short int     uInt16;
+typedef unsigned int           uInt32;
+typedef unsigned long long int uInt64;
+
+#endif