diff --git a/lzio.c b/lzio.c
index a09dbdad..24826f68 100644
--- a/lzio.c
+++ b/lzio.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lzio.c,v 1.30 2005/05/17 19:49:15 roberto Exp roberto $
+** $Id: lzio.c,v 1.31 2005/06/03 20:15:29 roberto Exp roberto $
 ** a generic input stream interface
 ** See Copyright Notice in lua.h
 */
@@ -22,10 +22,14 @@ int luaZ_fill (ZIO *z) {
   size_t size;
   lua_State *L = z->L;
   const char *buff;
+  if (z->eoz) return EOZ;
   lua_unlock(L);
   buff = z->reader(L, z->data, &size);
   lua_lock(L);
-  if (buff == NULL || size == 0) return EOZ;
+  if (buff == NULL || size == 0) {
+    z->eoz = 1;  /* avoid calling reader function next time */
+    return EOZ;
+  }
   z->n = size - 1;
   z->p = buff;
   return char2int(*(z->p++));
@@ -51,6 +55,7 @@ void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
   z->data = data;
   z->n = 0;
   z->p = NULL;
+  z->eoz = 0;
 }
 
 
diff --git a/lzio.h b/lzio.h
index 07365ad1..36a00900 100644
--- a/lzio.h
+++ b/lzio.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lzio.h,v 1.21 2005/05/17 19:49:15 roberto Exp roberto $
+** $Id: lzio.h,v 1.22 2009/05/18 17:26:25 roberto Exp roberto $
 ** Buffered streams
 ** See Copyright Notice in lua.h
 */
@@ -59,9 +59,10 @@ LUAI_FUNC int luaZ_lookahead (ZIO *z);
 struct Zio {
   size_t n;			/* bytes still unread */
   const char *p;		/* current position in buffer */
-  lua_Reader reader;
+  lua_Reader reader;		/* reader function */
   void* data;			/* additional data */
   lua_State *L;			/* Lua state (for reader) */
+  int eoz;			/* true if reader has no more data */
 };