--- a/src/core/ngx_hunk.h
+++ b/src/core/ngx_hunk.h
@@ -7,33 +7,39 @@
 #include <ngx_alloc.h>
 
 
-/* type */
+/* hunk type */
+
+/* temp means that hunk's content can be changed */
+/* other type means that hunk's content can not be changed */
 #define NGX_HUNK_TEMP       0x0001
 #define NGX_HUNK_MEMORY     0x0002
 #define NGX_HUNK_MMAP       0x0004
 #define NGX_HUNK_FILE       0x0008
-#define NGX_HUNK_FLUSH      0x0010
-/* in thread state flush means to write the hunk completely before return
-   in event-driven state flush means to start to write the hunk */
-#define NGX_HUNK_LAST       0x0020
+
+/* hunk flags */
 
-#define NGX_HUNK_IN_MEMORY  (NGX_HUNK_TEMP | NGX_HUNK_MEMORY | NGX_HUNK_MMAP )
-#define NGX_HUNK_TYPE       0x0ffff
+/* in thread state flush means to write the hunk completely before return */
+/* in event state flush means to start to write the hunk */
+#define NGX_HUNK_FLUSH      0x0100
+/* last hunk */
+#define NGX_HUNK_LAST       0x0200
+/* can be used with NGX_HUNK_LAST only */
+#define NGX_HUNK_SHUTDOWN   0x0400
 
-/* flags */
-#define NGX_HUNK_SHUTDOWN   0x10000
-/* can be used with NGX_HUNK_LAST only */
+
+#define NGX_HUNK_IN_MEMORY  (NGX_HUNK_TEMP|NGX_HUNK_MEMORY|NGX_HUNK_MMAP)
+
 
 
 typedef struct ngx_hunk_s ngx_hunk_t;
 struct ngx_hunk_s {
     union {
-        char    *p;             /* start of current data */
-        off_t    f;   
+        char    *mem;           /* start of current data */
+        off_t    file;   
     } pos;
     union {
-        char    *p;             /* end of current data */
-        off_t    f;   
+        char    *mem;           /* end of current data */
+        off_t    file;   
     } last;
     int          type;
     char        *start;         /* start of hunk */