diff --git a/qse/include/qse/cmn/Makefile.am b/qse/include/qse/cmn/Makefile.am
index 72550f3d..b0d5d5c3 100644
--- a/qse/include/qse/cmn/Makefile.am
+++ b/qse/include/qse/cmn/Makefile.am
@@ -2,7 +2,7 @@ pkgincludedir = $(includedir)/qse/cmn
 
 pkginclude_HEADERS = \
 	mem.h xma.h fma.h chr.h str.h lda.h htb.h rbt.h \
-	rex.h sll.h dll.h opt.h tio.h \
+	rex.h sll.h gdl.h dll.h opt.h tio.h \
 	fio.h pio.h sio.h time.h misc.h main.h stdio.h  
 
 if ENABLE_CXX
diff --git a/qse/include/qse/cmn/Makefile.in b/qse/include/qse/cmn/Makefile.in
index 2d0a093d..93c24dd9 100644
--- a/qse/include/qse/cmn/Makefile.in
+++ b/qse/include/qse/cmn/Makefile.in
@@ -52,8 +52,9 @@ CONFIG_CLEAN_VPATH_FILES =
 SOURCES =
 DIST_SOURCES =
 am__pkginclude_HEADERS_DIST = mem.h xma.h fma.h chr.h str.h lda.h \
-	htb.h rbt.h rex.h sll.h dll.h opt.h tio.h fio.h pio.h sio.h \
-	time.h misc.h main.h stdio.h Mmgr.hpp StdMmgr.hpp Mmged.hpp
+	htb.h rbt.h rex.h sll.h gdl.h dll.h opt.h tio.h fio.h pio.h \
+	sio.h time.h misc.h main.h stdio.h Mmgr.hpp StdMmgr.hpp \
+	Mmged.hpp
 am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`;
 am__vpath_adj = case $$p in \
     $(srcdir)/*) f=`echo "$$p" | sed "s|^$$srcdirstrip/||"`;; \
@@ -221,8 +222,8 @@ top_build_prefix = @top_build_prefix@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
 pkginclude_HEADERS = mem.h xma.h fma.h chr.h str.h lda.h htb.h rbt.h \
-	rex.h sll.h dll.h opt.h tio.h fio.h pio.h sio.h time.h misc.h \
-	main.h stdio.h $(am__append_1)
+	rex.h sll.h gdl.h dll.h opt.h tio.h fio.h pio.h sio.h time.h \
+	misc.h main.h stdio.h $(am__append_1)
 all: all-am
 
 .SUFFIXES:
diff --git a/qse/include/qse/cmn/dll.h b/qse/include/qse/cmn/dll.h
index 76280dbf..c895e561 100644
--- a/qse/include/qse/cmn/dll.h
+++ b/qse/include/qse/cmn/dll.h
@@ -1,5 +1,5 @@
 /*
- * $Id: dll.h 352 2010-08-31 13:20:34Z hyunghwan.chung $
+ * $Id: dll.h 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -21,162 +21,216 @@
 #ifndef _QSE_CMN_DLL_H_
 #define _QSE_CMN_DLL_H_
 
+/** @file
+ * This file defines a doubly linked list interface.
+ */
+
 #include <qse/types.h>
 #include <qse/macros.h>
+#include <qse/cmn/gdl.h>
 
-/**
- * The qse_dll_nhdr_t type defines a common node header fields used internally.
- */
-typedef struct qse_dll_nhdr_t qse_dll_nhdr_t;
-struct qse_dll_nhdr_t
-{
-	qse_dll_nhdr_t* next;
-	qse_dll_nhdr_t* prev;
-};
-
-#define __QSE_DLL_WRAP(x) do { x } while(0)
+#define QSE_DLL_DEFINE(list_type,node_type,data_define,manage_define) \
+	typedef struct list_type list_type; \
+	typedef struct node_type node_type; \
+	struct node_type \
+	{ \
+		node_type* prev; \
+		node_type* next; \
+		data_define \
+	}; \
+	struct list_type \
+	{ \
+		node_type   gdl; \
+		qse_size_t  size; \
+		manage_define \
+	}
 
 #define QSE_DLL_TYPE(data_type) qse_dll_ ## data_type ## _t
 #define QSE_DLL_NODE_TYPE(data_type) qse_dll_ ## data_type ## _node_t
 
 /**
- * The QSE_DLL_DEFINE macro defines a new doubly-linked list type for data
+ * The QSE_DLL_DEFINE_SIMPLE macro defines a doubly-linked list type for data
  * of the @a data_type type.
  */
-#define QSE_DLL_DEFINE(data_type) \
-	typedef struct QSE_DLL_TYPE(data_type) QSE_DLL_TYPE(data_type); \
-	typedef struct QSE_DLL_NODE_TYPE(data_type) QSE_DLL_NODE_TYPE(data_type); \
-	struct QSE_DLL_NODE_TYPE(data_type) \
-	{ \
-		QSE_DLL_NODE_TYPE(data_type)* next; \
-		QSE_DLL_NODE_TYPE(data_type)* prev; \
-		data_type data; \
-	}; \
-	struct QSE_DLL_TYPE(data_type) \
-	{ \
-		QSE_DLL_NODE_TYPE(data_type) link; \
-	}
+#define QSE_DLL_DEFINE_SIMPLE(data_type) \
+	QSE_DLL_DEFINE ( \
+		QSE_DLL_TYPE(data_type), \
+		QSE_DLL_NODE_TYPE(data_type), \
+		data_type data;, \
+	)
 
 /**
- * The QSE_DLL_DEFINE macro defines a new doubly-linked list type for data
+ * The QSE_DLL_DEFINE_MANAGED macro defines a doubly-linked list type for data
  * of the @a data_type type.
  */
 #define QSE_DLL_DEFINE_MANAGED(data_type,manage_type) \
-	typedef struct QSE_DLL_TYPE(data_type) QSE_DLL_TYPE(data_type); \
-	typedef struct QSE_DLL_NODE_TYPE(data_type) QSE_DLL_NODE_TYPE(data_type); \
-	struct QSE_DLL_NODE_TYPE(data_type) \
-	{ \
-		QSE_DLL_NODE_TYPE(data_type)* next; \
-		QSE_DLL_NODE_TYPE(data_type)* prev; \
-		data_type data; \
-	}; \
-	struct QSE_DLL_TYPE(data_type) \
-	{ \
-		QSE_DLL_NODE_TYPE(data_type) link; \
+	QSE_DLL_DEFINE ( \
+		QSE_DLL_TYPE(data_type), \
+		QSE_DLL_NODE_TYPE(data_type), \
+		data_type data;, \
 		manage_type data; \
-	}
+	)
 
-#define QSE_DLL_INIT(dll) __QSE_DLL_WRAP ( \
-	(dll)->link.next = &(dll)->link; \
-	(dll)->link.prev = &(dll)->link; \
-)
+#define QSE_DLL_INIT(dll) \
+	QSE_BLOCK ( \
+		QSE_GDL_INIT(&(dll)->gdl); \
+		(dll)->size = 0; \
+	)
 
-#define QSE_DLL_FINI(dll) __QSE_DLL_WRAP ( \
-	while (!QSE_DLL_ISEMPTY(dll)) QSE_DLL_DELHEAD(dll); \
-)
+#define QSE_DLL_FINI(dll) QSE_DLL_CLEAR(dll)
 
-#define QSE_DLL_CHAIN(dll,p,x,n) __QSE_DLL_WRAP ( \
-	register qse_dll_nhdr_t* __qse_dll_chain_prev = (qse_dll_nhdr_t*)(p); \
-	register qse_dll_nhdr_t* __qse_dll_chain_next = (qse_dll_nhdr_t*)(n); \
-	(x)->prev = (void*)__qse_dll_chain_prev; \
-	(x)->next = (void*)__qse_dll_chain_next; \
-	__qse_dll_chain_next->prev = (void*)(x); \
-	__qse_dll_chain_prev->next = (void*)(x); \
-)
+#define QSE_DLL_CHAIN(dll,p,x,n)  \
+	QSE_BLOCK ( \
+		QSE_GDL_CHAIN ((qse_gdl_t*)p, (qse_gdl_t*)x, (qse_gdl_t*)n); \
+		(dll)->size++; \
+	)
 
-#define QSE_DLL_UNCHAIN(dll,x) __QSE_DLL_WRAP ( \
-	register qse_dll_nhdr_t* __qse_dll_unchain_prev = \
-		(qse_dll_nhdr_t*)((x)->prev); \
-	register qse_dll_nhdr_t* __qse_dll_unchain_next = \
-		(qse_dll_nhdr_t*)((x)->next); \
-	__qse_dll_unchain_next->prev = __qse_dll_unchain_prev; \
-	__qse_dll_unchain_prev->next = __qse_dll_unchain_next; \
-)
+#define QSE_DLL_UNCHAIN(dll,x) \
+	QSE_BLOCK ( \
+		QSE_GDL_UNCHAIN ((qse_gdl_t*)x); \
+		(dll)->size--; \
+	)
 
-#define QSE_DLL_HEADNODE(dll) ((dll)->link.next)
-#define QSE_DLL_TAILNODE(dll) ((dll)->link.prev)
-#define QSE_DLL_NEXTNODE(dll,p) ((p)->next)
-#define QSE_DLL_PREVNODE(dll,p) ((p)->prev)
-#define QSE_DLL_ISVALIDNODE(dll,p) ((p) != &(dll)->link)
+#define QSE_DLL_CLEAR(dll) \
+	QSE_BLOCK ( \
+		while (!QSE_DLL_ISEMPTY(dll)) QSE_DLL_DELHEAD(dll); \
+	)
 
-#define QSE_DLL_ISEMPTY(dll) (QSE_DLL_HEADNODE(dll) == &(dll)->link)
-#define QSE_DLL_ADDHEAD(dll,x) QSE_DLL_CHAIN(dll,&(dll)->link,x,QSE_DLL_HEADNODE(dll))
-#define QSE_DLL_ADDTAIL(dll,x) QSE_DLL_CHAIN(dll,QSE_DLL_TAILNODE(dll),x,&(dll)->link)
-#define QSE_DLL_DELHEAD(dll) QSE_DLL_UNCHAIN(dll,QSE_DLL_HEADNODE(dll))
-#define QSE_DLL_DELTAIL(dll) QSE_DLL_UNCHAIN(dll,QSE_DLL_TAILNODE(dll))
-		
-/*
- * Doubly Linked List
+/**
+ * The QSE_DLL_ISEMPTY macro determines if a list @a dll is empty 
  */
+#define QSE_DLL_ISEMPTY(dll) QSE_GDL_ISEMPTY(&(dll)->gdl)
+
+/**
+ * The QSE_DLL_ISMEMBER macro determines if a node @a x is a member
+ * of a list @a dll.
+ */
+#define QSE_DLL_ISMEMBER(dll,x) ((x) != &(dll)->gdl)
+
+#define QSE_DLL_HEAD(dll) QSE_GDL_HEAD(&(dll)->gdl)
+#define QSE_DLL_TAIL(dll) QSE_GDL_TAIL(&(dll)->gdl)
+#define QSE_DLL_SIZE(dll) ((dll)->size)
+
+/**
+ * The QSE_DLL_ADDHEAD macro add a member node @a x to the head of 
+ * the list @a dll.
+ */
+#define QSE_DLL_ADDHEAD(dll,x) \
+	QSE_DLL_CHAIN(dll,&(dll)->gdl,x,QSE_DLL_HEAD(dll))
+
+/**
+ * The QSE_DLL_ADDHEAD macro add a member node @a x to the tail of 
+ * the list @a dll.
+ */
+#define QSE_DLL_ADDTAIL(dll,x) \
+	QSE_DLL_CHAIN(dll,QSE_DLL_TAIL(dll),x,&(dll)->gdl)
+
+/**
+ * The QSE_DLL_DELHEAD macro deletes the head node.
+ */
+#define QSE_DLL_DELHEAD(dll) \
+	QSE_DLL_UNCHAIN(dll,QSE_DLL_HEAD(dll))
+
+/**
+ * The QSE_DLL_DELTAIL macro deletes the tail node.
+ */
+#define QSE_DLL_DELTAIL(dll) \
+	QSE_DLL_UNCHAIN(dll,QSE_DLL_TAIL(dll))
+		
+
+/* ----------- more general implementation below ----------------- */
+enum qse_dll_walk_t
+{
+	QSE_DLL_WALK_STOP     = 0,
+	QSE_DLL_WALK_FORWARD  = 1,
+	QSE_DLL_WALK_BACKWARD = 2
+};
+typedef enum qse_dll_walk_t qse_dll_walk_t;
+
 typedef struct qse_dll_t qse_dll_t;
 typedef struct qse_dll_node_t qse_dll_node_t;
 
 /* data copier */
-typedef void* (*qse_dll_copier_t) (qse_dll_t* dll, void* dptr, qse_size_t dlen);
+typedef void* (*qse_dll_copier_t) (
+	qse_dll_t* dll,
+	void*      dptr,
+	qse_size_t dlen
+);
 
 /* data freeer */
-typedef void (*qse_dll_freeer_t) (qse_dll_t* dll, void* dptr, qse_size_t dlen);
+typedef void (*qse_dll_freeer_t) (
+	qse_dll_t* dll,
+	void*      dptr,
+	qse_size_t dlen
+);
+
+/**
+ * The qse_dll_comper_t type defines a key comparator that is called when
+ * the list needs to compare data. A doubly linked list is created with a
+ * default comparator that performs bitwise comparison.
+ *
+ * The comparator must return 0 if the data are the same and a non-zero
+ * integer otherwise.
+ */
+typedef int (*qse_dll_comper_t) (
+	qse_dll_t*  dll,   /**< doubly linked list */
+	const void* dptr1, /**< data pointer */
+	qse_size_t  dlen1, /**< data length */
+	const void* dptr2, /**< data pointer */
+	qse_size_t  dlen2  /**< data length */
+);
 
 /* node visitor */
-typedef int (*qse_dll_walker_t) (
-	qse_dll_t* dll, qse_dll_node_t* node, void* arg);
-
-struct qse_dll_t
-{
-	qse_mmgr_t* mmgr;
-
-	qse_dll_copier_t copier;
-	qse_dll_freeer_t freeer;
-
-	qse_size_t size;
-	qse_dll_node_t* head;
-	qse_dll_node_t* tail;
-};
+typedef qse_dll_walk_t (*qse_dll_walker_t) (
+	qse_dll_t*      dll, 
+	qse_dll_node_t* node,
+	void*           ctx
+);
 
+/**
+ * The qse_dll_node_t type defines a doubly linked list node.
+ */
 struct qse_dll_node_t
 {
-	void* dptr; /* pointer to the beginning of data */
-	qse_size_t dlen; /* length of data in bytes */
-	qse_dll_node_t* next; /* pointer to the next node */
-	qse_dll_node_t* prev; /* pointer to the prev node */
+	/* the first two fields in sync with qse_gdl_t */
+	qse_dll_node_t* prev;
+	qse_dll_node_t* next;
+
+	void*      dptr; /**< data pointer */
+	qse_size_t dlen; /**< data length */
 };
 
-
-enum qse_dll_walk_t
+/**
+ * The qse_dll_t type defines a doubly linked list.
+ */
+struct qse_dll_t
 {
-	QSE_DLL_WALK_STOP = 0,
-	QSE_DLL_WALK_FORWARD = 1
+	QSE_DEFINE_COMMON_FIELDS (dll)
+
+	qse_dll_node_t gdl;
+	qse_size_t     size;
+
+	qse_byte_t       scale;  
+	qse_dll_copier_t copier; 
+	qse_dll_freeer_t freeer;
+	qse_dll_comper_t comper;
 };
 
-#define QSE_DLL_COPIER_INLINE qse_dll_copyinline
+#define QSE_DLL_COPIER_SIMPLE ((qse_dll_copier_t)1)
+#define QSE_DLL_COPIER_INLINE ((qse_dll_copier_t)2)
 
-#define QSE_DLL_HEAD(dll) ((dll)->head)
-#define QSE_DLL_TAIL(dll) ((dll)->tail)
-#define QSE_DLL_SIZE(dll) ((dll)->size)
+#define QSE_DLL_SCALE(dll) ((dll)->scale)
+#define QSE_DLL_DPTR(node) ((node)->dptr)
+#define QSE_DLL_DLEN(node) ((node)->dlen)
 
-#define QSE_DLL_DPTR(n) ((n)->dptr)
-#define QSE_DLL_DLEN(n) ((n)->dlen)
-#define QSE_DLL_NEXT(n) ((n)->next)
-#define QSE_DLL_PREV(n) ((n)->prev)
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-/* 
- * NAME: creates a doubly linked list with extension area
- *
- * DESCRIPTION:
+QSE_DEFINE_COMMON_FUNCTIONS (dll)
+
+/** 
  *  The qse_dll_open() function creates an empty doubly linked list.
  *  If the memory manager mmgr is QSE_NULL, the function gets the default
  *  memory manager with QSE_MMGR_GETMMGR() and uses it if it is not QSE_NULL.
@@ -185,141 +239,175 @@ extern "C" {
  *  after initializing the main area. The extension initializer is passed
  *  the pointer to the doubly linked list created.
  *
- * RETURNS: 
+ * @return
  *  the pointer to a newly created doubly linked list on success.
  *  QSE_NULL on failure.
- *
- * WARNING:
- *  In the debug build, it fails the assertion if QSE_MMGR_SETMMGR() returns
- *  QSE_NULL when QSE_NULL is passed as the first parameter. In the release
- *  build, it returns QSE_NULL if such a thing happens. 
  */
-
 qse_dll_t* qse_dll_open (
-	qse_mmgr_t* mmgr /* memory manager */ , 
-	qse_size_t ext /* size of extension area in bytes */
+	qse_mmgr_t* mmgr,   /**< memory manager */ 
+	qse_size_t  xtnsize /**< size of extension area in bytes */
 );
 
-/* 
- * NAME destroys a singly linked list 
+/** 
+ * The qse_dll_close() function destroys a doubly linked list.
  */
 void qse_dll_close (
-	qse_dll_t* dll /* a singly linked list */
+	qse_dll_t* dll /** doubly linked list */
 );
 
-/* 
- * NAME deletes all elements of a singly linked list 
+/**
+ * The qse_dll_init() function initializes a statically declared list.
  */
-void qse_dll_clear (
-	qse_dll_t* dll /* a singly linked list */
+qse_dll_t* qse_dll_init (
+	qse_dll_t*  dll, /**< doubly linked list */
+	qse_mmgr_t* mmgr /**< memory manager */
 );
 
-/*
- * NAME specifies how to clone an element
- *
- * DESCRIPTION
- *  A special copier QSE_DLL_COPIER_INLINE is provided. This copier enables
- *  you to copy the data inline to the internal node. No freeer is invoked
- *  when the node is freeed.
- *
- *  You may set the copier to QSE_NULL to perform no special operation 
- *  when the data pointer is rememebered.
+/**
+ * The qse_dll_fini() function finalizes a statically initialized list.
+ */
+void qse_dll_fini (
+	qse_dll_t* dll /**< doubly linked list */
+);
+
+/**
+ * The qse_dll_getscale() function gets the scale factor
+ */
+int qse_dll_getscale (
+	qse_dll_t* dll  /**< doubly linked list */
+);
+
+/**
+ *  The qse_dll_setscale() function sets the scale factor of the data length.
+ *  A scale factor determines the actual length of data in bytes. A doubly 
+ *  linked list created with a scale factor of 1. The scale factor should be
+ *  larger than 0 and less than 256.
+ */
+void qse_dll_setscale (
+	qse_dll_t* dll,     /**< doubly linked list */
+	int        scale    /**< scale factor */
+);
+
+/**
+ * The qse_dll_setcopier() function changes the element copier.
+ * A special copier QSE_DLL_COPIER_INLINE is provided. This copier enables
+ * you to copy the data inline to the internal node. No freeer is invoked
+ * when the node is freeed. You may set the copier to QSE_NULL to perform
+ * no special operation when the data pointer is rememebered.
  */
 void qse_dll_setcopier (
-	qse_dll_t* dll /* a singly linked list */, 
-	qse_dll_copier_t copier /* a element copier */
+	qse_dll_t*       dll,   /**< doubly linked list */
+	qse_dll_copier_t copier /**< element copier */
 );
 
+/**
+ * The qse_dll_getcopier() function returns the element copier.
+ */
 qse_dll_copier_t qse_dll_getcopier (
-	qse_dll_t* dll /* a singly linked list */
+	qse_dll_t* dll /**< doubly linked list */
 );
 
-/*
- * NAME specifies how to destroy an element
- *
- * DESCRIPTION
- *  The freeer is called when a node containing the element is destroyed.
+/**
+ * The qse_dll_setfreeer() function changes the element freeer.
+ * The freeer is called when a node containing the element is destroyed.
  */
 void qse_dll_setfreeer (
-	qse_dll_t* dll /* a singly linked list */,
-	qse_dll_freeer_t freeer /* a element freeer */
+	qse_dll_t*       dll,   /**< doubly linked list */
+	qse_dll_freeer_t freeer /**< element freeer */
 );
 
+/**
+ * The qse_dll_getfreeer() function returns the element freeer.
+ */
 qse_dll_freeer_t qse_dll_getfreeer (
-	qse_dll_t* dll /* a singly linked list */
+	qse_dll_t* dll /**< doubly linked list */
 );
 
-/*
- * NAME Gets the pointer to the extension area
- * RETURN the pointer to the extension area
- */
-void* qse_dll_getxtn (
-	qse_dll_t* dll /* a singly linked list */
-);
-
-/*
- * NAME: get the pointer to the memory manager in use 
- */
-qse_mmgr_t* qse_dll_getmmgr (
-	qse_dll_t* dll /* a singly linked list */
-);
-
-void qse_dll_setmmgr (qse_dll_t* dll, qse_mmgr_t* mmgr);
-
-/*
- * NAME Gets the number of elements held in a singly linked list
- * RETURN the number of elements the list holds
+/**
+ * The qse_dll_getsize() function returns the number of the data nodes held
+ * in a doubly linked list.
  */
 qse_size_t qse_dll_getsize (
-	qse_dll_t* dll /* a singly linked list */
+	qse_dll_t* dll  /**< doubly linked list */
 );
 
-/*
- * NAME Gets the head(first) node 
- * RETURN the tail node of a singly linked list
+/**
+ * The qse_dll_gethead() function gets the head node. You may use the 
+ * #QSE_DLL_HEAD macro instead.
  */
 qse_dll_node_t* qse_dll_gethead (
-	qse_dll_t* dll /* a singly linked list */
+	qse_dll_t* dll  /**< doubly linked list */
 );
 
-/* 
- * NAME Gets the tail(last) node 
- * RETURN the tail node of a singly linked list
+/**
+ * The qse_dll_gettail() function gets the head node. You may use the 
+ * #QSE_DLL_TAIL macro instead.
  */
 qse_dll_node_t* qse_dll_gettail (
-	qse_dll_t* dll /* a singly linked list */
+	qse_dll_t* dll  /**< doubly linked list */
 );
 
-/* 
- * NAME Inserts data before a positional node given 
- *
- * DESCRIPTION
- *   Inserts data.
+
+qse_dll_node_t* qse_dll_search (
+	qse_dll_t*      dll,   /**< doubly linked list */
+	qse_dll_node_t* pos,   /**< positional node */
+	const void*     dptr,  /**< data pointer */
+	qse_size_t      dlen   /**< data length */
+);
+
+qse_dll_node_t* qse_dll_rsearch (
+	qse_dll_t*      dll,   /**< doubly linked list */
+	qse_dll_node_t* pos,   /**< positional node */
+	const void*     dptr,  /**< data pointer */
+	qse_size_t      dlen   /**< data length */
+);
+
+/**
+ * The qse_dll_insert() function insert an element into a list 
  */
 qse_dll_node_t* qse_dll_insert (
-	qse_dll_t* dll /* a singly linked list */,
-	qse_dll_node_t* pos /* a node before which a new node is inserted */,
-	void* dptr /* the pointer to the data */ ,
-	qse_size_t dlen /* the length of the data in bytes */
+	qse_dll_t*      dll,  /**< doubly linked list */
+	qse_dll_node_t* pos,  /**< node before which a new node is inserted */
+	void*           dptr, /**< data pointer */
+	qse_size_t      dlen  /**< data length */
+);
+
+void qse_dll_delete (
+	qse_dll_t*      dll, 
+	qse_dll_node_t* pos
+);
+
+/** 
+ * The qse_dll_clear() functions deletes all elements of a list
+ */
+void qse_dll_clear (
+	qse_dll_t* dll /**< doubly linked list */
+);
+
+void qse_dll_walk (
+	qse_dll_t*       dll,    /**< doubly linked list */
+	qse_dll_walker_t walker, /**< user-defined walker function */
+	void*            ctx     /**< pointer to user-defined data */
+);
+
+void qse_dll_rwalk (
+	qse_dll_t*       dll,    /**< doubly linked list */
+	qse_dll_walker_t walker, /**< user-defined walker function */
+	void*            ctx     /**< pointer to user-defined data */
 );
 
 qse_dll_node_t* qse_dll_pushhead (
-	qse_dll_t* dll /* a singly linked list */,
-	void* dptr, 
+	qse_dll_t* dll, /* doubly linked list */
+	void*      dptr, 
 	qse_size_t dlen
 );
 
 qse_dll_node_t* qse_dll_pushtail (
-	qse_dll_t* dll /* a singly linked list */, 
-	void* dptr, 
+	qse_dll_t* dll, /* doubly linked list */ 
+	void*      dptr, 
 	qse_size_t dlen
 );
 
-void qse_dll_delete (
-	qse_dll_t* dll, 
-	qse_dll_node_t* pos
-);
-
 void qse_dll_pophead (
 	qse_dll_t* dll
 );
@@ -328,36 +416,6 @@ void qse_dll_poptail (
 	qse_dll_t* dll
 );
 
-/* 
- * NAME Traverses s singly linked list 
- *
- * DESCRIPTION
- *   A singly linked list allows uni-directional in-order traversal.
- *   The qse_dll_walk() function traverses a singly linkked list from its 
- *   head node down to its tail node as long as the walker function returns 
- *   QSE_DLL_WALK_FORWARD. A walker can return QSE_DLL_WALK_STOP to cause 
- *   immediate stop of traversal.
- *   For each node, the walker function is called and it is passed three
- *   parameters: the singly linked list, the visiting node, and the 
- *   user-defined data passed as the third parameter in a call to the 
- *   qse_dll_walk() function.
- */
-void qse_dll_walk (
-	qse_dll_t* dll /* a singly linked list */,
-	qse_dll_walker_t walker /* a user-defined walker function */,
-	void* arg /* pointer to user-defined data */
-);
-
-/* 
- * Causes a singly linked list to copy in data to a node.
- * Use QSE_DLL_COPIER_INLINE instead.
- */
-void* qse_dll_copyinline (
-	qse_dll_t* dll /* a singly linked list */,
-	void* data /* pointer to data to copy */ , 
-	qse_size_t len /* length of data in bytes */
-);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/qse/include/qse/cmn/gdl.h b/qse/include/qse/cmn/gdl.h
new file mode 100644
index 00000000..e186fc84
--- /dev/null
+++ b/qse/include/qse/cmn/gdl.h
@@ -0,0 +1,70 @@
+/*
+ * $Id$
+ */
+
+#ifndef _QSE_CMN_GDL_H_
+#define _QSE_CMN_GDL_H_
+
+/** @file
+ * This file defins a generic double link and provides basic macros to 
+ * manipulate a chain of links.
+ */
+
+/**
+ * The qse_gdl_t type defines a structure to contain forward and 
+ * backward links. 
+ */
+typedef struct qse_gdl_t qse_gdl_t;
+struct qse_gdl_t
+{
+	qse_gdl_t* prev;
+	qse_gdl_t* next;
+};
+
+/**
+ * The QSE_GDL_INIT macro initializes a host link to be used for internal
+ * management.
+ */
+#define QSE_GDL_INIT(host) QSE_BLOCK ( \
+	(host)->next = (host); (host)->prev = (host); \
+)
+
+/**
+ * The QSE_GDL_CHAIN macro chains a new member node @a x between 
+ * two nodes @a p and @a n.
+ */
+#define QSE_GDL_CHAIN(p,x,n) qse_gdl_chain(p,x,n)
+
+/**
+ * The QSE_GDL_UNCHAIN macro unchains a member node @a x.
+ */
+#define QSE_GDL_UNCHAIN(x) qse_gdl_unchain(x)
+
+/**
+ * The QSE_GDL_ISEMPTY macro checks if the chain is empty.
+ */
+#define QSE_GDL_ISEMPTY(host) ((host)->next == (host))
+
+/**
+ * The QSE_GDL_HEAD macro get the first node in the chain.
+ */
+#define QSE_GDL_HEAD(host) ((host)->next)
+
+/**
+ * The QSE_GDL_TAIL macro gets the last node in the chain.
+ */
+#define QSE_GDL_TAIL(host) ((host)->prev)
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void qse_gdl_chain (qse_gdl_t* p, qse_gdl_t* x, qse_gdl_t* n);
+void qse_gdl_unchain (qse_gdl_t* x);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/qse/include/qse/cmn/htb.h b/qse/include/qse/cmn/htb.h
index 0991c6bc..456efac8 100644
--- a/qse/include/qse/cmn/htb.h
+++ b/qse/include/qse/cmn/htb.h
@@ -1,5 +1,5 @@
 /*
- * $Id: htb.h 341 2010-08-04 07:25:48Z hyunghwan.chung $
+ * $Id: htb.h 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -38,7 +38,7 @@ typedef struct qse_htb_pair_t qse_htb_pair_t;
  */
 enum qse_htb_walk_t
 {
-        QSE_HTB_WALK_STOP = 0,
+        QSE_HTB_WALK_STOP    = 0,
         QSE_HTB_WALK_FORWARD = 1
 };
 typedef enum qse_htb_walk_t qse_htb_walk_t;
diff --git a/qse/include/qse/cmn/map.h b/qse/include/qse/cmn/map.h
index d476540b..4dc16b58 100644
--- a/qse/include/qse/cmn/map.h
+++ b/qse/include/qse/cmn/map.h
@@ -58,7 +58,7 @@
 #	define qse_map_clear(map)                       qse_htb_clear(map)
 #	define qse_map_walk(map,walker,ctx)             qse_htb_walk(map,walker,ctx)
 #	define QSE_MAP_WALK_STOP                        QSE_HTB_WALK_STOP
-#	define QSE_MAP_WALK_FORWARD                     QSE_HTB_WALK_FORWARD
+#	define QSE_MAP_WALK_FORWARD                    QSE_HTB_WALK_FORWARD
 #	define qse_map_walk_t                           qse_htb_walk_t
 #	define QSE_MAP_KEY                              QSE_HTB_KEY
 #	define QSE_MAP_VAL                              QSE_HTB_VAL
@@ -111,7 +111,7 @@
 #	define qse_map_clear(map)                       qse_rbt_clear(map)
 #	define qse_map_walk(map,walker,ctx)             qse_rbt_walk(map,walker,ctx)
 #	define QSE_MAP_WALK_STOP                        QSE_RBT_WALK_STOP
-#	define QSE_MAP_WALK_FORWARD                     QSE_RBT_WALK_FORWARD
+#	define QSE_MAP_WALK_FORWARD                    QSE_RBT_WALK_FORWARD
 #	define qse_map_walk_t                           qse_rbt_walk_t
 #	define QSE_MAP_KEY                              QSE_RBT_KEY
 #	define QSE_MAP_VAL                              QSE_RBT_VAL
diff --git a/qse/include/qse/cmn/rbt.h b/qse/include/qse/cmn/rbt.h
index d4219b29..f18ff390 100644
--- a/qse/include/qse/cmn/rbt.h
+++ b/qse/include/qse/cmn/rbt.h
@@ -37,7 +37,7 @@ typedef struct qse_rbt_pair_t qse_rbt_pair_t;
  */
 enum qse_rbt_walk_t
 {
-        QSE_RBT_WALK_STOP = 0,
+        QSE_RBT_WALK_STOP    = 0,
         QSE_RBT_WALK_FORWARD = 1
 };
 typedef enum qse_rbt_walk_t qse_rbt_walk_t;
diff --git a/qse/include/qse/cmn/sll.h b/qse/include/qse/cmn/sll.h
index 1bd21ea6..2611b02d 100644
--- a/qse/include/qse/cmn/sll.h
+++ b/qse/include/qse/cmn/sll.h
@@ -1,5 +1,5 @@
 /*
- * $Id: sll.h 328 2010-07-08 06:58:44Z hyunghwan.chung $
+ * $Id: sll.h 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -25,7 +25,7 @@
 #include <qse/macros.h>
 
 /** @file
- * Singly linked list
+ * This file provides a singly linked list interface.
  */
 
 /**
@@ -33,13 +33,14 @@
  */
 enum qse_sll_walk_t
 {
-	QSE_SLL_WALK_STOP    = 0,  /**< stop traversal */
-	QSE_SLL_WALK_FORWARD = 1   /**< traverse to the next node */
+	QSE_SLL_WALK_STOP     = 0,  /**< stop traversal */
+	QSE_SLL_WALK_FORWARD  = 1   /**< traverse to the next node */
 };
+typedef enum qse_sll_walk_t qse_sll_walk_t;
+
 
 typedef struct qse_sll_t      qse_sll_t;
 typedef struct qse_sll_node_t qse_sll_node_t;
-typedef enum   qse_sll_walk_t qse_sll_walk_t;
 
 /**
  * The qse_sll_copier_t type defines a callback function for node construction.
@@ -89,16 +90,15 @@ typedef int (*qse_sll_comper_t) (
  * The qse_sll_walker_t type defines a list traversal callback for each node.
  * The qse_sll_walk() calls a callback function of the type qse_sll_walker_t
  * for each node until it returns QSE_SLL_WALK_STOP. The walker should return
- * QSE_SLL_WALK_FORWARD to let qse_sll_walk() continue visiting the next node.
+ * QSE_SLL_WALK_FORWARD  to let qse_sll_walk() continue visiting the next node.
  * The third parameter to qse_sll_walk() is passed to the walker as the third
  * parameter.
  */
 typedef qse_sll_walk_t (*qse_sll_walker_t) (
-	qse_sll_t*      sll,   /* singly linked list */
-	qse_sll_node_t* node,  /* visited node */
-	void*           arg    /* user-defined data */
+	qse_sll_t*      sll,   /**< singly linked list */
+	qse_sll_node_t* node,  /**< visited node */
+	void*           ctx    /**< user-defined data */
 );
-/******/
 
 /**
  * The qse_sll_t type defines a singly lnked list.
@@ -183,203 +183,128 @@ qse_sll_t* qse_sll_open (
 	qse_size_t  ext   /* size of extension area in bytes */
 );
 
-/****f* Common/qse_sll_close
- * NAME
- *  qse_sll_close - destroy a singly linked list 
- *
- * DESCRIPTION
- *  The qse_sll_close() function destroys a singly linked list freeing up
- *  the memory.
- *
- * SYNOPSIS
+/**
+ * The qse_sll_close() function destroys a singly linked list freeing up
+ * the memory.
  */
 void qse_sll_close (
-	qse_sll_t* sll /* a singly linked list */
+	qse_sll_t* sll /**< singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_init
- * NAME
- *  qse_sll_init - initialize a singly linked list
- *
- * DESCRIPTION
- *  The qse_sll_init() function initializes a singly linked list. The memory
- *  should be allocated by a caller and be passed to it. The caller may declare
- *  a static variable of the qse_sll_t type and pass its address. A memory 
- *  manager still needs to be passed for node manipulation later.
+/**
+ * The qse_sll_init() function initializes a statically declared singly 
+ * linked list. The memory should be allocated by a caller and be passed 
+ * to it. The caller may declare a static variable of the qse_sll_t type
+ * and pass its address. A memory manager still needs to be passed for 
+ * node manipulation later.
  *  
- * RETURN
+ * @return
  *  The qse_sll_init() function returns the first parameter on success and
  *  QSE_NULL on failure.
- * 
- * SYNOPSIS
  */
 qse_sll_t* qse_sll_init (
-	qse_sll_t*  sll   /* an uninitialized singly linked list */,
-	qse_mmgr_t* mmgr  /* a memory manager */
+	qse_sll_t*  sll,  /* singly linked list */
+	qse_mmgr_t* mmgr  /* memory manager */
 );
-/******/
 
-/****f* Common/qse_sll_fini
- * NAME
- *  qse_sll_init - deinitialize a singly linked list
- *
- * SYNOPSIS
+/**
+ * The qse_sll_fini() function finalizes a statically initialized list.
  */
 void qse_sll_fini (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /**< singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_getsize
- * NAME
- *  qse_sll_getsize - get the number of nodes
- *
- * DESCRIPTION
- *  The qse_sll_getsize() function returns the number of the data nodes held
- *  in a singly linked list.
- *
- * SYNOPSIS
- */
-qse_size_t qse_sll_getsize (
-	qse_sll_t* sll  /* a singly linked list */
-);
-/******/
-
-
-/****f* Common/qse_sll_getscale
- * NAME
- *  qse_sll_getscale - get the scale factor
- *
- * SYNOPSIS
+/**
+ * The qse_sll_getscale() function gets the scale factor
  */
 int qse_sll_getscale (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /**< singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_setscale
- * NAME
- *  qse_sll_setscale - set the scale factor
- *
- * DESCRIPTION 
+/**
  *  The qse_sll_setscale() function sets the scale factor of the data length.
  *  A scale factor determines the actual length of data in bytes. A singly 
  *  linked list created with a scale factor of 1. The scale factor should be
  *  larger than 0 and less than 256.
- *
- * NOTES
- *  It is a bad idea to change the scale factor when a sll is not empty.
- *  
- * SYNOPSIS
  */
 void qse_sll_setscale (
-	qse_sll_t* sll /* a singly linked list */,
-	int scale      /* a scale factor */
+	qse_sll_t* sll,     /**< singly linked list */
+	int        scale    /**< scale factor */
 );
-/******/
 
-/****f* Common/qse_sll_getcopier
- * NAME
- *  qse_sll_getfreeer - get the data copier
- *
- * SYNOPSIS
+/**
+ * The qse_sll_getfreeer() function gets the data copier.
  */
 qse_sll_copier_t qse_sll_getcopier (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /* singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_setcopier
- * NAME 
- *  qse_sll_setcopier - set a data copier
- *
- * DESCRIPTION
- *  A special copier QSE_SLL_COPIER_INLINE is provided. This copier enables
- *  you to copy the data inline to the internal node. No freeer is invoked
- *  when the node is freeed.
- *
- *  You may set the copier to QSE_NULL to perform no special operation 
- *  when the data pointer is rememebered.
- * 
- * SYNOPSIS
+/**
+ * The qse_sll_setcopier() function changes the element copier.
+ * A special copier QSE_SLL_COPIER_INLINE is provided. This copier enables
+ * you to copy the data inline to the internal node. No freeer is invoked
+ * when the node is freeed. You may set the copier to QSE_NULL to perform 
+ * no special operation when the data pointer is rememebered.
  */
 void qse_sll_setcopier (
-	qse_sll_t* sll          /* a singly linked list */, 
-	qse_sll_copier_t copier /* a data copier */
+	qse_sll_t*       sll,   /**< singly linked list */
+	qse_sll_copier_t copier /**< data copier */
 );
-/******/
 
-/****f* Common/qse_sll_getfreeer
- * NAME
- *  qse_sll_getfreeer - get the data freeer
- *
- * SYNOPSIS
+/**
+ * The qse_sll_getfreeer() function returns the element freeer.
  */
 qse_sll_freeer_t qse_sll_getfreeer (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /**< singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_setfreeer
- * NAME
- *  qse_sll_setfreeer - set a data freeer
- *
- * DESCRIPTION
- *  The freeer is called when a node containing the element is destroyed.
- * 
- * SYNOPSIS
+/**
+ * The qse_sll_setfreeer() function changes the element freeer.
+ * The freeer is called when a node containing the element is destroyed.
  */
 void qse_sll_setfreeer (
-	qse_sll_t* sll          /* a singly linked list */,
-	qse_sll_freeer_t freeer /* a data freeer */
+	qse_sll_t*       sll,   /**< singly linked list */
+	qse_sll_freeer_t freeer /**< data freeer */
 );
-/******/
 
-/****f* Common/qse_sll_getcomper
- * NAME
- *  qse_sll_getcomper - get the data comparator
- *
- * SYNOPSIS
+/**
+ * The qse_sll_getcomper() function returns the data comparator.
  */
 qse_sll_comper_t qse_sll_getcomper (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /**< singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_setcomper
- * NAME
- *  qse_sll_setcomper - set the data comparator
- *
- * SYNOPSIS
+/**
+ * The qse_sll_setcomper() function changes  the data comparator
  */
 void qse_sll_setcomper (
-	qse_sll_t*       sll     /* a singly linked list */,
-	qse_sll_comper_t comper  /* a comparator */
+	qse_sll_t*       sll     /**< singly linked list */,
+	qse_sll_comper_t comper  /**< comparator */
 );
-/******/
 
-/****f* Common/qse_sll_gethead
- * NAME
- *  qse_sll_gethead - get the head node
- *
- * SYNOPSIS
+/**
+ * The qse_sll_getsize() function returns the number of the data nodes held
+ * in a singly linked list.
+ */
+qse_size_t qse_sll_getsize (
+	qse_sll_t* sll  /** singly linked list */
+);
+
+/**
+ * The qse_sll_gethead() function gets the head node. You may use the 
+ * #QSE_SLL_HEAD macro instead.
  */
 qse_sll_node_t* qse_sll_gethead (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /**< a singly linked list */
 );
-/******/
 
-/****f* Common/qse_sll_gettail
- * NAME
- *  qse_sll_gettail - get the tail node
- *
- * SYNOPSIS
+/**
+ * The qse_sll_gettail() function gets the head node. You may use the 
+ * #QSE_SLL_TAIL macro instead.
  */
 qse_sll_node_t* qse_sll_gettail (
-	qse_sll_t* sll  /* a singly linked list */
+	qse_sll_t* sll  /**< singly linked list */
 );
-/******/
 
 /**
  * The qse_sll_search() function traverses a list to find a node containing
@@ -387,8 +312,8 @@ qse_sll_node_t* qse_sll_gettail (
  * from the next node of the positional node. If the positional node is 
  * QSE_NULL, the traversal begins from the head node. 
  *
- * Note that no reverse search is provided because a reverse traversal can not be 
- * achieved efficiently.
+ * Note that no reverse search is provided because a reverse traversal can not 
+ * be achieved efficiently.
  *
  * @return pointer to the node found. QSE_NULL if no match is found
  */
@@ -430,31 +355,10 @@ void qse_sll_clear (
 	qse_sll_t* sll  /**< singly linked list */
 );
 
-qse_sll_node_t* qse_sll_pushhead (
-	qse_sll_t* sll /**< singly linked list */,
-	void*      dptr, 
-	qse_size_t dlen
-);
-
-qse_sll_node_t* qse_sll_pushtail (
-	qse_sll_t* sll /**< singly linked list */, 
-	void*      dptr, 
-	qse_size_t dlen
-);
-
-
-void qse_sll_pophead (
-	qse_sll_t* sll
-);
-
-void qse_sll_poptail (
-	qse_sll_t* sll
-);
-
 /**
  *  The qse_sll_walk() function traverses a singly linkked list from its 
  *  head node down to its tail node as long as the walker function returns 
- *  QSE_SLL_WALK_FORWARD. A walker can return QSE_SLL_WALK_STOP to cause 
+ *  QSE_SLL_WALK_FORWARD . A walker can return QSE_SLL_WALK_STOP to cause 
  *  immediate stop of traversal.
  * 
  *  For each node, the walker function is called and it is passed three
@@ -468,6 +372,26 @@ void qse_sll_walk (
 	void*            ctx      /**< the pointer to user-defined data */
 );
 
+qse_sll_node_t* qse_sll_pushhead (
+	qse_sll_t* sll /**< singly linked list */,
+	void*      dptr, 
+	qse_size_t dlen
+);
+
+qse_sll_node_t* qse_sll_pushtail (
+	qse_sll_t* sll /**< singly linked list */, 
+	void*      dptr, 
+	qse_size_t dlen
+);
+
+void qse_sll_pophead (
+	qse_sll_t* sll
+);
+
+void qse_sll_poptail (
+	qse_sll_t* sll
+);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/qse/include/qse/cmn/str.h b/qse/include/qse/cmn/str.h
index a70b16f1..2cf54b9b 100644
--- a/qse/include/qse/cmn/str.h
+++ b/qse/include/qse/cmn/str.h
@@ -1,5 +1,5 @@
 /*
- * $Id: str.h 353 2010-09-01 13:19:59Z hyunghwan.chung $
+ * $Id: str.h 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -25,10 +25,11 @@
 #include <qse/macros.h>
 
 /** @file
- *  Various functions, types, macros for string manipulation.
+ * This file provides various functions, types, macros for string manipulation.
+ *
+ * The #qse_cstr_t type and the #qse_xstr_t defined in <qse/types.h> help you
+ * deal with a string pointer and length in a structure.
  *
- *  The qse_cstr_t type and the qse_xstr_t defined in <qse/types.h> helps you
- *  dealing with a string pointer and length.
  */
 
 #define QSE_STR_LEN(s)       ((s)->len)      /**< string length */
@@ -170,17 +171,25 @@ qse_size_t qse_strxcpy (
 	const qse_char_t* str
 );
 
+/**
+ * The qse_strycpy() function copies a length-bounded string into
+ * a buffer with unknown size. 
+ */
 qse_size_t qse_strncpy (
-	qse_char_t*       buf, 
-	const qse_char_t* str,
-	qse_size_t        len
+	qse_char_t*       buf, /**< buffer with unknown length */
+	const qse_char_t* str, /**< length-bounded string */
+	qse_size_t        len  /**< string length */
 );
 
+/**
+ * The qse_strycpy() function copies a length-bounded string into
+ * a length-bounded buffer.
+ */
 qse_size_t qse_strxncpy (
-	qse_char_t*       buf,
-	qse_size_t        bsz,
-	const qse_char_t* str,
-	qse_size_t        len
+	qse_char_t*       buf, /**< length-bounded buffer */
+	qse_size_t        bsz, /**< buffer length */
+	const qse_char_t* str, /**< length-bounded string */
+	qse_size_t        len  /**< string length */
 );
 
 /**
@@ -189,13 +198,13 @@ qse_size_t qse_strxncpy (
  * buffer.
  */
 qse_size_t qse_strxput (
-        qse_char_t*       buf, 
+	qse_char_t*       buf, 
 	qse_size_t        bsz,
 	const qse_char_t* str
 );
 
 qse_size_t qse_strxnput (
-        qse_char_t*       buf,
+	qse_char_t*       buf,
 	qse_size_t        bsz,
 	const qse_char_t* str,
 	qse_size_t        len
@@ -226,8 +235,8 @@ qse_size_t qse_strfcpy (
  * @sa qse_strfcpy, qse_strxfcpy, qse_strxfncpy
  */
 qse_size_t qse_strfncpy (
-        qse_char_t*       buf,
-        const qse_char_t* fmt, 
+	qse_char_t*       buf,
+	const qse_char_t* fmt, 
 	const qse_cstr_t  str[]
 );
 
@@ -256,9 +265,9 @@ qse_size_t qse_strxfcpy (
  * @sa qse_strfcpy, qse_strfncpy, qse_strxfcpy
  */
 qse_size_t qse_strxfncpy (
-        qse_char_t*       buf,
+	qse_char_t*       buf,
 	qse_size_t        bsz,
-        const qse_char_t* fmt,
+	const qse_char_t* fmt,
 	const qse_cstr_t  str[]
 );
 
@@ -281,11 +290,11 @@ qse_size_t qse_strxfncpy (
  * @endcode
  */
 qse_size_t qse_strxsubst (
-        qse_char_t*            buf,
+	qse_char_t*            buf,
 	qse_size_t             bsz,
 	const qse_char_t*      fmt,
 	qse_strxsubst_subst_t  subst,
-        void*                  ctx
+	void*                  ctx
 );
 
 qse_size_t qse_strxcat (
@@ -308,15 +317,15 @@ int qse_strcmp (
 
 int qse_strxcmp (
 	const qse_char_t* s1,
-	qse_size_t len1,
+	qse_size_t        len1,
 	const qse_char_t* s2
 );
 
 int qse_strxncmp (
 	const qse_char_t* s1,
-	qse_size_t len1, 
+	qse_size_t        len1, 
 	const qse_char_t* s2,
-	qse_size_t len2
+	qse_size_t        len2
 );
 
 int qse_strcasecmp (
@@ -505,17 +514,25 @@ qse_char_t* qse_strxbeg (
 	const qse_char_t* sub)
 ;
 
+/*
+ * The qse_strbeg() function checks if the a string begins with a substring.
+ * @return @a str on match, QSE_NULL on no match
+ */
 qse_char_t* qse_strnbeg (
 	const qse_char_t* str,
 	const qse_char_t* sub,
-	qse_size_t len
+	qse_size_t        len
 );
 
+/*
+ * The qse_strbeg() function checks if the a string begins with a substring.
+ * @return @a str on match, QSE_NULL on no match
+ */
 qse_char_t* qse_strxnbeg (
 	const qse_char_t* str,
-	qse_size_t len1, 
+	qse_size_t        len1, 
 	const qse_char_t* sub,
-	qse_size_t len2
+	qse_size_t        len2
 );
 
 /**
@@ -565,25 +582,76 @@ qse_char_t* qse_strxnend (
 /* 
  * string conversion
  */
-int qse_strtoi (const qse_char_t* str);
-long qse_strtol (const qse_char_t* str);
-unsigned int qse_strtoui (const qse_char_t* str);
-unsigned long qse_strtoul (const qse_char_t* str);
+int qse_strtoi (
+	const qse_char_t* str
+);
 
-int qse_strxtoi (const qse_char_t* str, qse_size_t len);
-long qse_strxtol (const qse_char_t* str, qse_size_t len);
-unsigned int qse_strxtoui (const qse_char_t* str, qse_size_t len);
-unsigned long qse_strxtoul (const qse_char_t* str, qse_size_t len);
+long qse_strtol (
+	const qse_char_t* str
+);
 
-qse_int_t qse_strtoint (const qse_char_t* str);
-qse_long_t qse_strtolong (const qse_char_t* str);
-qse_uint_t qse_strtouint (const qse_char_t* str);
-qse_ulong_t qse_strtoulong (const qse_char_t* str);
+unsigned int qse_strtoui (
+	const qse_char_t* str
+);
 
-qse_int_t qse_strxtoint (const qse_char_t* str, qse_size_t len);
-qse_long_t qse_strxtolong (const qse_char_t* str, qse_size_t len);
-qse_uint_t qse_strxtouint (const qse_char_t* str, qse_size_t len);
-qse_ulong_t qse_strxtoulong (const qse_char_t* str, qse_size_t len);
+unsigned long qse_strtoul (
+	const qse_char_t* str
+);
+
+int qse_strxtoi (
+	const qse_char_t* str,
+	qse_size_t        len
+);
+
+long qse_strxtol (
+	const qse_char_t* str,
+	qse_size_t        len
+);
+
+unsigned int qse_strxtoui (
+	const qse_char_t* str,
+	qse_size_t        len
+);
+
+unsigned long qse_strxtoul (
+	const qse_char_t* str,
+	qse_size_t        len
+);
+
+qse_int_t qse_strtoint (
+	const qse_char_t* str
+);
+
+qse_long_t qse_strtolong (
+	const qse_char_t* str
+);
+
+qse_uint_t qse_strtouint (
+	const qse_char_t* str
+);
+
+qse_ulong_t qse_strtoulong (
+	const qse_char_t* str
+);
+
+qse_int_t qse_strxtoint (
+	const qse_char_t* str, qse_size_t len
+);
+
+qse_long_t qse_strxtolong (
+	const qse_char_t* str,
+	qse_size_t        len
+);
+
+qse_uint_t qse_strxtouint (
+	const qse_char_t* str,
+	qse_size_t        len
+);
+
+qse_ulong_t qse_strxtoulong (
+	const qse_char_t* str,
+	qse_size_t        len
+);
 
 /**
  * The qse_strspl() function splits a string into fields.
@@ -595,7 +663,6 @@ int qse_strspl (
 	qse_char_t        rquote,
 	qse_char_t        escape
 );
-/******/
 
 /**
  * The qse_strspltrn() function splits a string translating special 
diff --git a/qse/include/qse/macros.h b/qse/include/qse/macros.h
index 179d3eaf..9210d238 100644
--- a/qse/include/qse/macros.h
+++ b/qse/include/qse/macros.h
@@ -1,5 +1,5 @@
 /*
- * $Id: macros.h 348 2010-08-26 06:26:28Z hyunghwan.chung $
+ * $Id: macros.h 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -29,26 +29,35 @@
 
 #if defined(__STDC_VERSION__) && (__STDC_VERSION__>=199901L)
 #	define QSE_INLINE inline
+#	define QSE_HAVE_INLINE
 #elif defined(__GNUC__) && defined(__GNUC_GNU_INLINE__)
 #	define QSE_INLINE /*extern*/ inline
+#	define QSE_HAVE_INLINE
 #else
 #	define QSE_INLINE 
+#	undef QSE_HAVE_INLINE
 #endif
 
 #if defined(__GNUC__)
 #	define QSE_INLINE_ALWAYS inline __attribute__((__always_inline__))
+#	define QSE_HAVE_INLINE_ALWAYS
 #elif defined(_MSC_VER) || (defined(__CC_ARM) || defined(__ARMCC__))
 #	define QSE_INLINE_ALWAYS __forceinline
+#	define QSE_HAVE_INLINE_ALWAYS
 #else
 #	define QSE_INLINE_ALWAYS QSE_INLINE
+#	undef QSE_HAVE_INLINE_ALWAYS
 #endif
 
 #if defined(__GNUC__)
 #	define QSE_INLINE_NEVER inline __attribute__((__noinline__))
+#	define QSE_HAVE_INLINE_NEVER
 #elif (defined(__CC_ARM) || defined(__ARMCC__))
 #	define QSE_INLINE_NEVER __declspec(noinline)
+#	define QSE_HAVE_INLINE_NEVER
 #else
 #	define QSE_INLINE_NEVER 
+#	undef QSE_HAVE_INLINE_NEVER
 #endif
 
 
@@ -142,14 +151,20 @@
 #define QSE_TYPE_MIN(type) \
 	((QSE_TYPE_IS_SIGNED(type)? QSE_TYPE_SIGNED_MIN(type): QSE_TYPE_UNSIGNED_MIN(type)))
 
+/**
+ * The QSE_BLOCK macro encloses one or more statements in a block with 
+ * no side-effect.
+ */
+#define QSE_BLOCK(code) do { code } while(0)
+
 #define QSE_IS_POWOF2(x) (((x) & ((x) - 1)) == 0)
 
 #define QSE_SWAP(x,y,original_type,casting_type) \
-	do { \
+	QSE_BLOCK ( \
 		x = (original_type)((casting_type)(x) ^ (casting_type)(y)); \
 		y = (original_type)((casting_type)(y) ^ (casting_type)(x)); \
 		x = (original_type)((casting_type)(x) ^ (casting_type)(y)); \
-	} while (0)
+	)
 
 #define QSE_ABS(x) ((x) < 0? -(x): (x))
 
@@ -162,7 +177,7 @@
 #define QSE_END_LOOP(id)      QSE_LOOP_CONTINUE(id) } __loop_ ## id ## _end__:
 
 #define QSE_REPEAT(n,blk) \
-	do { \
+	QSE_BLOCK ( \
 		qse_size_t __qse_repeat_x1__ = (qse_size_t)(n); \
 		qse_size_t __qse_repeat_x2__ = __qse_repeat_x1__ >> 4; \
 		__qse_repeat_x1__ &= 15; \
@@ -171,7 +186,8 @@
 			blk; blk; blk; blk; blk; blk; blk; blk; \
 			blk; blk; blk; blk; blk; blk; blk; blk; \
 		} \
-	} while (0);
+	)
+
 
 /* number of characters to number of bytes */
 #define QSE_NCTONB(x) ((x)*sizeof(qse_char_t))
diff --git a/qse/lib/cmn/Makefile.am b/qse/lib/cmn/Makefile.am
index 65cda218..bdcd37d9 100644
--- a/qse/lib/cmn/Makefile.am
+++ b/qse/lib/cmn/Makefile.am
@@ -7,7 +7,7 @@ libqsecmn_la_SOURCES = \
 	syscall.h mem.h \
 	mem.c xma.c fma.c chr.c chr_cnv.c rex.c \
 	str_bas.c str_cnv.c str_dyn.c str_utl.c \
-	lda.c htb.c rbt.c sll.c dll.c opt.c \
+	lda.c htb.c rbt.c sll.c gdl.c dll.c opt.c \
 	tio.c tio_get.c tio_put.c \
 	fio.c pio.c sio.c \
 	time.c \
diff --git a/qse/lib/cmn/Makefile.in b/qse/lib/cmn/Makefile.in
index 86f1cbd4..517144ca 100644
--- a/qse/lib/cmn/Makefile.in
+++ b/qse/lib/cmn/Makefile.in
@@ -75,7 +75,7 @@ LTLIBRARIES = $(lib_LTLIBRARIES)
 libqsecmn_la_DEPENDENCIES =
 am_libqsecmn_la_OBJECTS = mem.lo xma.lo fma.lo chr.lo chr_cnv.lo \
 	rex.lo str_bas.lo str_cnv.lo str_dyn.lo str_utl.lo lda.lo \
-	htb.lo rbt.lo sll.lo dll.lo opt.lo tio.lo tio_get.lo \
+	htb.lo rbt.lo sll.lo gdl.lo dll.lo opt.lo tio.lo tio_get.lo \
 	tio_put.lo fio.lo pio.lo sio.lo time.lo misc.lo assert.lo \
 	main.lo stdio.lo
 libqsecmn_la_OBJECTS = $(am_libqsecmn_la_OBJECTS)
@@ -264,7 +264,7 @@ libqsecmn_la_SOURCES = \
 	syscall.h mem.h \
 	mem.c xma.c fma.c chr.c chr_cnv.c rex.c \
 	str_bas.c str_cnv.c str_dyn.c str_utl.c \
-	lda.c htb.c rbt.c sll.c dll.c opt.c \
+	lda.c htb.c rbt.c sll.c gdl.c dll.c opt.c \
 	tio.c tio_get.c tio_put.c \
 	fio.c pio.c sio.c \
 	time.c \
@@ -363,6 +363,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/dll.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fio.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fma.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gdl.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/htb.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/lda.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/main.Plo@am__quote@
diff --git a/qse/lib/cmn/dll.c b/qse/lib/cmn/dll.c
index 5e94e15a..e5ec58d8 100644
--- a/qse/lib/cmn/dll.c
+++ b/qse/lib/cmn/dll.c
@@ -1,5 +1,5 @@
 /*
- * $Id: dll.c 287 2009-09-15 10:01:02Z hyunghwan.chung $
+ * $Id: dll.c 354 2010-09-03 12:50:08Z hyunghwan.chung $
  * 
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -21,7 +21,31 @@
 #include <qse/cmn/dll.h>
 #include "mem.h"
 
-qse_dll_t* qse_dll_open (qse_mmgr_t* mmgr, qse_size_t ext)
+QSE_IMPLEMENT_COMMON_FUNCTIONS (dll)
+
+#define TOB(dll,len) ((len)*(dll)->scale)
+
+static int default_comper (
+	qse_dll_t* dll, 
+	const void* dptr1, size_t dlen1, 
+	const void* dptr2, size_t dlen2)
+{
+	if (dlen1 == dlen2) return QSE_MEMCMP (dptr1, dptr2, TOB(dll,dlen1));
+	/* it just returns 1 to indicate that they are different. */
+	return 1;
+
+#if 0
+	qse_size_t min = (dlen1 < dlen2)? dlen1: dlen2;
+	int n = QSE_MEMCMP (dptr1, dptr2, TOB(dll,min));
+	if (n == 0 && dlen1 != dlen2)
+	{
+		n = (dlen1 > dlen2)? 1: -1;
+	}
+	return n;
+#endif
+}
+
+qse_dll_t* qse_dll_open (qse_mmgr_t* mmgr, qse_size_t xtnsize)
 {
 	qse_dll_t* dll;
 
@@ -35,56 +59,60 @@ qse_dll_t* qse_dll_open (qse_mmgr_t* mmgr, qse_size_t ext)
 		if (mmgr == QSE_NULL) return QSE_NULL;
 	}
 
-	dll = QSE_MMGR_ALLOC (mmgr, QSE_SIZEOF(qse_dll_t) + ext);
+	dll = QSE_MMGR_ALLOC (mmgr, QSE_SIZEOF(qse_dll_t) + xtnsize);
 	if (dll == QSE_NULL) return QSE_NULL;
 
-	/* do not zero the extension */
-	QSE_MEMSET (dll, 0, QSE_SIZEOF(qse_dll_t));
-	dll->mmgr = mmgr;
+	if (qse_dll_init (dll, mmgr) == QSE_NULL)
+	{
+		QSE_MMGR_FREE (mmgr, dll);
+		return QSE_NULL;
+	}
 
 	return dll;
 }
 
 void qse_dll_close (qse_dll_t* dll)
 {
-	qse_dll_clear (dll);
+	qse_dll_fini (dll);
 	QSE_MMGR_FREE (dll->mmgr, dll);
 }
 
-void qse_dll_clear (qse_dll_t* dll)
+qse_dll_t* qse_dll_init (qse_dll_t* dll, qse_mmgr_t* mmgr)
 {
-	while (dll->head != QSE_NULL) qse_dll_delete (dll, dll->head);
-	QSE_ASSERT (dll->tail == QSE_NULL);
-}
+	if (mmgr == QSE_NULL) mmgr = QSE_MMGR_GETDFL();
 
-void* qse_dll_getxtn (qse_dll_t* dll)
-{
-	return dll + 1;
-}
+	/* do not zero out the xtnsizeension */
+	QSE_MEMSET (dll, 0, QSE_SIZEOF(*dll));
 
-qse_mmgr_t* qse_dll_getmmgr (qse_dll_t* dll)
-{
-        return dll->mmgr;
-}
-
-void qse_dll_setmmgr (qse_dll_t* dll, qse_mmgr_t* mmgr)
-{
 	dll->mmgr = mmgr;
+	dll->scale = 1;
+
+	dll->comper = default_comper;
+	dll->copier = QSE_DLL_COPIER_SIMPLE;
+
+	QSE_DLL_INIT (dll);
+	return dll;
 }
 
-qse_size_t qse_dll_getsize (qse_dll_t* dll)
+void qse_dll_fini (qse_dll_t* dll)
 {
-	return dll->size;
+	qse_dll_clear (dll);
 }
 
-qse_dll_node_t* qse_dll_gethead (qse_dll_t* dll)
+int qse_dll_getscale (qse_dll_t* dll)
 {
-	return dll->head;
+	return dll->scale;
 }
 
-qse_dll_node_t* qse_dll_gettail (qse_dll_t* dll)
+void qse_dll_setscale (qse_dll_t* dll, int scale)
 {
-	return dll->tail;
+	QSE_ASSERTX (scale > 0 && scale <= QSE_TYPE_MAX(qse_byte_t), 
+		"The scale should be larger than 0 and less than or equal to the maximum value that the qse_byte_t type can hold");
+
+	if (scale <= 0) scale = 1;
+	if (scale > QSE_TYPE_MAX(qse_byte_t)) scale = QSE_TYPE_MAX(qse_byte_t);
+
+	dll->scale = scale;
 }
 
 qse_dll_copier_t qse_dll_getcopier (qse_dll_t* dll)
@@ -94,6 +122,7 @@ qse_dll_copier_t qse_dll_getcopier (qse_dll_t* dll)
 
 void qse_dll_setcopier (qse_dll_t* dll, qse_dll_copier_t copier)
 {
+	if (copier == QSE_NULL) copier = QSE_DLL_COPIER_SIMPLE;
 	dll->copier = copier;
 }
 
@@ -107,11 +136,37 @@ void qse_dll_setfreeer (qse_dll_t* dll, qse_dll_freeer_t freeer)
 	dll->freeer = freeer;
 }
 
+qse_dll_comper_t qse_dll_getcomper (qse_dll_t* dll)
+{
+	return dll->comper;
+}
+
+void qse_dll_setcomper (qse_dll_t* dll, qse_dll_comper_t comper)
+{
+	if (comper == QSE_NULL) comper = default_comper;
+	dll->comper = comper;
+}
+
+qse_size_t qse_dll_getsize (qse_dll_t* dll)
+{
+	return QSE_DLL_SIZE(dll);
+}
+
+qse_dll_node_t* qse_dll_gethead (qse_dll_t* dll)
+{
+	return QSE_DLL_HEAD(dll);
+}
+
+qse_dll_node_t* qse_dll_gettail (qse_dll_t* dll)
+{
+	return QSE_DLL_TAIL(dll);
+}
+
 static qse_dll_node_t* alloc_node (qse_dll_t* dll, void* dptr, qse_size_t dlen)
 {
 	qse_dll_node_t* n;
 
-	if (dll->copier == QSE_NULL)
+	if (dll->copier == QSE_DLL_COPIER_SIMPLE)
 	{
 		n = QSE_MMGR_ALLOC (dll->mmgr, QSE_SIZEOF(qse_dll_node_t));
 		if (n == QSE_NULL) return QSE_NULL;
@@ -119,10 +174,11 @@ static qse_dll_node_t* alloc_node (qse_dll_t* dll, void* dptr, qse_size_t dlen)
 	}
 	else if (dll->copier == QSE_DLL_COPIER_INLINE)
 	{
-		n = QSE_MMGR_ALLOC (dll->mmgr, QSE_SIZEOF(qse_dll_node_t) + dlen);
+		n = QSE_MMGR_ALLOC (dll->mmgr, 
+			QSE_SIZEOF(qse_dll_node_t) + TOB(dll,dlen));
 		if (n == QSE_NULL) return QSE_NULL;
 
-		QSE_MEMCPY (n + 1, dptr, dlen);
+		QSE_MEMCPY (n + 1, dptr, TOB(dll,dlen));
 		n->dptr = n + 1;
 	}
 	else
@@ -138,51 +194,132 @@ static qse_dll_node_t* alloc_node (qse_dll_t* dll, void* dptr, qse_size_t dlen)
 	}
 
 	n->dlen = dlen; 
-	n->next = QSE_NULL;	
-	n->prev = QSE_NULL;
-
 	return n;
 }
 
+static QSE_INLINE void free_node (qse_dll_t* dll, qse_dll_node_t* node)
+{
+	if (dll->freeer != QSE_NULL)
+	{
+		/* free the actual data */
+		dll->freeer (dll, node->dptr, node->dlen);
+	}
+
+	/* free the node */
+	QSE_MMGR_FREE (dll->mmgr, node);
+}
+
+qse_dll_node_t* qse_dll_search (
+	qse_dll_t* dll, qse_dll_node_t* pos, const void* dptr, qse_size_t dlen)
+{
+	if (pos == QSE_NULL) pos = QSE_DLL_HEAD(dll);
+
+	while (QSE_DLL_ISMEMBER(dll,pos))
+	{
+		if (dll->comper (dll, pos->dptr, pos->dlen, dptr, dlen) == 0)
+		{
+			return pos;
+		}
+
+		pos = pos->next;
+	}	
+
+	return QSE_NULL;
+}
+
+qse_dll_node_t* qse_dll_rsearch (
+	qse_dll_t* dll, qse_dll_node_t* pos, const void* dptr, qse_size_t dlen)
+{
+	if (pos == QSE_NULL) pos = QSE_DLL_TAIL(dll);
+
+	while (QSE_DLL_ISMEMBER(dll,pos))
+	{
+		if (dll->comper (dll, pos->dptr, pos->dlen, dptr, dlen) == 0)
+		{
+			return pos;
+		}
+
+		pos = pos->prev;
+	}	
+
+	return QSE_NULL;
+}
+
 qse_dll_node_t* qse_dll_insert (
 	qse_dll_t* dll, qse_dll_node_t* pos, void* dptr, qse_size_t dlen)
 {
 	qse_dll_node_t* n = alloc_node (dll, dptr, dlen);
-	if (n == QSE_NULL) return QSE_NULL;
-
-	if (pos == QSE_NULL)
+	if (n)
 	{
-		/* insert at the end */
-		if (dll->head == QSE_NULL)
+		if (pos == QSE_NULL)
 		{
-			QSE_ASSERT (dll->tail == QSE_NULL);
-			dll->head = n;
+			/* insert at the end */
+			QSE_DLL_ADDTAIL (dll, n);
 		}
-		else dll->tail->next = n;
-
-		dll->tail = n;
-	}
-	else
-	{
-		/* insert in front of the positional node */
-		n->next = pos;
-		if (pos == dll->head) dll->head = n;
 		else
 		{
-			/* take note of performance penalty */
-			qse_dll_node_t* n2 = dll->head;
-			while (n2->next != pos) n2 = n2->next;
-			n2->next = n;
+			/* insert in front of the positional node */
+			QSE_DLL_CHAIN (dll, pos->prev, n, pos);
 		}
 	}
 
-	dll->size++;
 	return n;
 }
 
+void qse_dll_delete (qse_dll_t* dll, qse_dll_node_t* pos)
+{
+	if (pos == QSE_NULL || !QSE_DLL_ISMEMBER(dll,pos)) return;
+	QSE_DLL_UNCHAIN (dll, pos);
+	free_node (dll, pos);
+}
+
+void qse_dll_clear (qse_dll_t* dll)
+{
+	while (!QSE_DLL_ISEMPTY(dll))
+	{
+		qse_dll_delete (dll, QSE_DLL_HEAD(dll));
+	}
+}
+
+void qse_dll_walk (qse_dll_t* dll, qse_dll_walker_t walker, void* ctx)
+{
+	qse_dll_node_t* n = QSE_DLL_HEAD(dll);
+	qse_dll_walk_t w = QSE_DLL_WALK_FORWARD;
+
+	while (QSE_DLL_ISMEMBER(dll,n))
+	{
+		qse_dll_node_t* nxt = n->next;
+		qse_dll_node_t* prv = n->prev;
+
+		w = walker (dll, n, ctx);
+
+		if (w == QSE_DLL_WALK_FORWARD) n = nxt;
+		else if (w == QSE_DLL_WALK_BACKWARD) n = prv;
+		else break;
+	}
+}
+
+void qse_dll_rwalk (qse_dll_t* dll, qse_dll_walker_t walker, void* ctx)
+{
+	qse_dll_node_t* n = QSE_DLL_TAIL(dll);
+	qse_dll_walk_t w = QSE_DLL_WALK_BACKWARD;
+
+	while (QSE_DLL_ISMEMBER(dll,n))
+	{
+		qse_dll_node_t* nxt = n->next;
+		qse_dll_node_t* prv = n->prev;
+
+		w = walker (dll, n, ctx);
+
+		if (w == QSE_DLL_WALK_FORWARD) n = nxt;
+		else if (w == QSE_DLL_WALK_BACKWARD) n = prv;
+		else break;
+	}
+}
+
 qse_dll_node_t* qse_dll_pushhead (qse_dll_t* dll, void* data, qse_size_t size)
 {
-	return qse_dll_insert (dll, dll->head, data, size);
+	return qse_dll_insert (dll, QSE_DLL_HEAD(dll), data, size);
 }
 
 qse_dll_node_t* qse_dll_pushtail (qse_dll_t* dll, void* data, qse_size_t size)
@@ -190,67 +327,16 @@ qse_dll_node_t* qse_dll_pushtail (qse_dll_t* dll, void* data, qse_size_t size)
 	return qse_dll_insert (dll, QSE_NULL, data, size);
 }
 
-void qse_dll_delete (qse_dll_t* dll, qse_dll_node_t* pos)
-{
-	if (pos == QSE_NULL) return; /* not a valid node */
-
-	if (pos == dll->head)
-	{
-		/* it is simple to delete the head node */
-		dll->head = pos->next;
-		if (dll->head == QSE_NULL) dll->tail = QSE_NULL;
-	}
-	else 
-	{
-		/* but deletion of other nodes has significant performance
-		 * penalty as it has look for the predecessor of the 
-		 * target node */
-		qse_dll_node_t* n2 = dll->head;
-		while (n2->next != pos) n2 = n2->next;
-
-		n2->next = pos->next;
-
-		/* update the tail node if necessary */
-		if (pos == dll->tail) dll->tail = n2;
-	}
-
-	if (dll->freeer != QSE_NULL)
-	{
-		/* free the actual data */
-		dll->freeer (dll, pos->dptr, pos->dlen);
-	}
-
-	/* free the node */
-	QSE_MMGR_FREE (dll->mmgr, pos);
-
-	/* decrement the number of elements */
-	dll->size--;
-}
-
 void qse_dll_pophead (qse_dll_t* dll)
 {
-	qse_dll_delete (dll, dll->head);
+	QSE_ASSERT (!QSE_DLL_ISEMPTY(dll));
+	QSE_DLL_DELHEAD (dll);
 }
 
 void qse_dll_poptail (qse_dll_t* dll)
 {
-	qse_dll_delete (dll, dll->tail);
+	QSE_ASSERT (!QSE_DLL_ISEMPTY(dll));
+	QSE_DLL_DELTAIL (dll);
 }
 
-void qse_dll_walk (qse_dll_t* dll, qse_dll_walker_t walker, void* arg)
-{
-	qse_dll_node_t* n = dll->head;
-
-	while (n != QSE_NULL)
-	{
-		if (walker(dll,n,arg) == QSE_DLL_WALK_STOP) return;
-		n = n->next;
-	}
-}
-
-void* qse_dll_copyinline (qse_dll_t* dll, void* dptr, qse_size_t dlen)
-{
-	/* this is a dummy copier */
-	return QSE_NULL;
-}
 
diff --git a/qse/lib/cmn/gdl.c b/qse/lib/cmn/gdl.c
new file mode 100644
index 00000000..23015be4
--- /dev/null
+++ b/qse/lib/cmn/gdl.c
@@ -0,0 +1,33 @@
+/*
+ * $Id$
+ *
+    Copyright 2006-2009 Chung, Hyung-Hwan.
+    This file is part of QSE.
+
+    QSE is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as 
+    published by the Free Software Foundation, either version 3 of 
+    the License, or (at your option) any later version.
+
+    QSE is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public 
+    License along with QSE. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <qse/cmn/gdl.h>
+
+void qse_gdl_chain (qse_gdl_t* p, qse_gdl_t* x, qse_gdl_t* n)
+{
+	x->prev = p; x->next = n; n->prev = x; p->next = x;
+}
+
+void qse_gdl_unchain (qse_gdl_t* x)
+{
+	qse_gdl_t* p = x->prev;
+	qse_gdl_t* n = x->next;
+	n->prev = p; p->next = n;
+}
diff --git a/qse/lib/cmn/lda.c b/qse/lib/cmn/lda.c
index 6df8bdc1..38093083 100644
--- a/qse/lib/cmn/lda.c
+++ b/qse/lib/cmn/lda.c
@@ -1,5 +1,5 @@
 /*
- * $Id: lda.c 348 2010-08-26 06:26:28Z hyunghwan.chung $
+ * $Id: lda.c 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -207,22 +207,22 @@ void qse_lda_setcomper (lda_t* lda, comper_t comper)
 
 keeper_t qse_lda_getkeeper (lda_t* lda)
 {
-        return lda->keeper;
+	return lda->keeper;
 }
 
 void qse_lda_setkeeper (lda_t* lda, keeper_t keeper)
 {
-        lda->keeper = keeper;
+	lda->keeper = keeper;
 }
 
 sizer_t qse_lda_getsizer (lda_t* lda)
 {
-        return lda->sizer;
+	return lda->sizer;
 }
 
 void qse_lda_setsizer (lda_t* lda, sizer_t sizer)
 {
-        lda->sizer = sizer;
+	lda->sizer = sizer;
 }
 
 size_t qse_lda_getsize (lda_t* lda)
@@ -527,7 +527,7 @@ size_t qse_lda_walk (lda_t* lda, walker_t walker, void* ctx)
 	{
 		if (lda->node[i] != QSE_NULL) 
 		{
-                	w = walker (lda, i, ctx);
+               w = walker (lda, i, ctx);
 			nwalks++;
 		}
 
diff --git a/qse/lib/cmn/sll.c b/qse/lib/cmn/sll.c
index df480f23..62e3c07a 100644
--- a/qse/lib/cmn/sll.c
+++ b/qse/lib/cmn/sll.c
@@ -1,5 +1,5 @@
 /*
- * $Id: sll.c 348 2010-08-26 06:26:28Z hyunghwan.chung $
+ * $Id: sll.c 354 2010-09-03 12:50:08Z hyunghwan.chung $
  *
     Copyright 2006-2009 Chung, Hyung-Hwan.
     This file is part of QSE.
@@ -44,13 +44,23 @@ QSE_IMPLEMENT_COMMON_FUNCTIONS (sll)
 #define size_t    qse_size_t
 #define mmgr_t    qse_mmgr_t
 
-static int comp_data (sll_t* sll, 
+static int default_comper (sll_t* sll, 
 	const void* dptr1, size_t dlen1, 
 	const void* dptr2, size_t dlen2)
 {
 	if (dlen1 == dlen2) return QSE_MEMCMP (dptr1, dptr2, TOB(sll,dlen1));
 	/* it just returns 1 to indicate that they are different. */
 	return 1;
+
+#if 0
+	size_t min = (dlen1 < dlen2)? dlen1: dlen2;
+	int n = QSE_MEMCMP (dptr1, dptr2, TOB(sll,min));
+	if (n == 0 && dlen1 != dlen2)
+	{
+		n = (dlen1 > dlen2)? 1: -1;
+	}
+	return n;
+#endif
 }
 
 static node_t* alloc_node (sll_t* sll, void* dptr, size_t dlen)
@@ -133,7 +143,7 @@ sll_t* qse_sll_init (sll_t* sll, mmgr_t* mmgr)
 	sll->size = 0;
 	sll->scale = 1;
 
-	sll->comper = comp_data;
+	sll->comper = default_comper;
 	sll->copier = QSE_SLL_COPIER_SIMPLE;
 	return sll;
 }
@@ -187,7 +197,7 @@ comper_t qse_sll_getcomper (sll_t* sll)
 
 void qse_sll_setcomper (sll_t* sll, comper_t comper)
 {
-	if (comper == QSE_NULL) comper = comp_data;
+	if (comper == QSE_NULL) comper = default_comper;
 	sll->comper = comper;
 }
 
@@ -301,6 +311,18 @@ void qse_sll_clear (sll_t* sll)
 	QSE_ASSERT (TAIL(sll) == QSE_NULL);
 }
 
+void qse_sll_walk (sll_t* sll, walker_t walker, void* ctx)
+{
+	node_t* n = HEAD(sll);
+
+	while (n != QSE_NULL)
+	{
+		qse_sll_node_t* nxt = NEXT(n);
+		if (walker(sll,n,ctx) == QSE_SLL_WALK_STOP) return;
+		n = nxt;
+	}
+}
+
 node_t* qse_sll_pushhead (sll_t* sll, void* data, size_t size)
 {
 	return qse_sll_insert (sll, HEAD(sll), data, size);
@@ -321,14 +343,4 @@ void qse_sll_poptail (sll_t* sll)
 	qse_sll_delete (sll, TAIL(sll));
 }
 
-void qse_sll_walk (sll_t* sll, walker_t walker, void* ctx)
-{
-	node_t* n = HEAD(sll);
-
-	while (n != QSE_NULL)
-	{
-		if (walker(sll,n,ctx) == QSE_SLL_WALK_STOP) return;
-		n = NEXT(n);
-	}
-}
 
diff --git a/qse/samples/cmn/Makefile.am b/qse/samples/cmn/Makefile.am
index a188f22e..afe80d3c 100644
--- a/qse/samples/cmn/Makefile.am
+++ b/qse/samples/cmn/Makefile.am
@@ -1,6 +1,6 @@
 AM_CPPFLAGS = -I$(top_srcdir)/include -DNDEBUG
 
-bin_PROGRAMS = xma fma chr str sll lda htb rbt fio pio sio time main rex01 
+bin_PROGRAMS = xma fma chr str sll dll lda htb rbt fio pio sio time main rex01 
 
 LDFLAGS = -L../../lib/cmn 
 LDADD = -lqsecmn 
@@ -10,6 +10,7 @@ fma_SOURCES = fma.c
 chr_SOURCES = chr.c
 str_SOURCES = str.c
 sll_SOURCES = sll.c
+dll_SOURCES = dll.c
 lda_SOURCES = lda.c
 htb_SOURCES = htb.c
 rbt_SOURCES = rbt.c
diff --git a/qse/samples/cmn/Makefile.in b/qse/samples/cmn/Makefile.in
index b0238b5b..a90d27de 100644
--- a/qse/samples/cmn/Makefile.in
+++ b/qse/samples/cmn/Makefile.in
@@ -35,9 +35,9 @@ POST_UNINSTALL = :
 build_triplet = @build@
 host_triplet = @host@
 bin_PROGRAMS = xma$(EXEEXT) fma$(EXEEXT) chr$(EXEEXT) str$(EXEEXT) \
-	sll$(EXEEXT) lda$(EXEEXT) htb$(EXEEXT) rbt$(EXEEXT) \
-	fio$(EXEEXT) pio$(EXEEXT) sio$(EXEEXT) time$(EXEEXT) \
-	main$(EXEEXT) rex01$(EXEEXT)
+	sll$(EXEEXT) dll$(EXEEXT) lda$(EXEEXT) htb$(EXEEXT) \
+	rbt$(EXEEXT) fio$(EXEEXT) pio$(EXEEXT) sio$(EXEEXT) \
+	time$(EXEEXT) main$(EXEEXT) rex01$(EXEEXT)
 subdir = samples/cmn
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
@@ -58,6 +58,10 @@ am_chr_OBJECTS = chr.$(OBJEXT)
 chr_OBJECTS = $(am_chr_OBJECTS)
 chr_LDADD = $(LDADD)
 chr_DEPENDENCIES =
+am_dll_OBJECTS = dll.$(OBJEXT)
+dll_OBJECTS = $(am_dll_OBJECTS)
+dll_LDADD = $(LDADD)
+dll_DEPENDENCIES =
 am_fio_OBJECTS = fio.$(OBJEXT)
 fio_OBJECTS = $(am_fio_OBJECTS)
 fio_LDADD = $(LDADD)
@@ -123,14 +127,14 @@ CCLD = $(CC)
 LINK = $(LIBTOOL) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) \
 	--mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) $(AM_LDFLAGS) \
 	$(LDFLAGS) -o $@
-SOURCES = $(chr_SOURCES) $(fio_SOURCES) $(fma_SOURCES) $(htb_SOURCES) \
-	$(lda_SOURCES) $(main_SOURCES) $(pio_SOURCES) $(rbt_SOURCES) \
-	$(rex01_SOURCES) $(sio_SOURCES) $(sll_SOURCES) $(str_SOURCES) \
-	$(time_SOURCES) $(xma_SOURCES)
-DIST_SOURCES = $(chr_SOURCES) $(fio_SOURCES) $(fma_SOURCES) \
+SOURCES = $(chr_SOURCES) $(dll_SOURCES) $(fio_SOURCES) $(fma_SOURCES) \
 	$(htb_SOURCES) $(lda_SOURCES) $(main_SOURCES) $(pio_SOURCES) \
 	$(rbt_SOURCES) $(rex01_SOURCES) $(sio_SOURCES) $(sll_SOURCES) \
 	$(str_SOURCES) $(time_SOURCES) $(xma_SOURCES)
+DIST_SOURCES = $(chr_SOURCES) $(dll_SOURCES) $(fio_SOURCES) \
+	$(fma_SOURCES) $(htb_SOURCES) $(lda_SOURCES) $(main_SOURCES) \
+	$(pio_SOURCES) $(rbt_SOURCES) $(rex01_SOURCES) $(sio_SOURCES) \
+	$(sll_SOURCES) $(str_SOURCES) $(time_SOURCES) $(xma_SOURCES)
 ETAGS = etags
 CTAGS = ctags
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
@@ -280,6 +284,7 @@ fma_SOURCES = fma.c
 chr_SOURCES = chr.c
 str_SOURCES = str.c
 sll_SOURCES = sll.c
+dll_SOURCES = dll.c
 lda_SOURCES = lda.c
 htb_SOURCES = htb.c
 rbt_SOURCES = rbt.c
@@ -369,6 +374,9 @@ clean-binPROGRAMS:
 chr$(EXEEXT): $(chr_OBJECTS) $(chr_DEPENDENCIES) 
 	@rm -f chr$(EXEEXT)
 	$(LINK) $(chr_OBJECTS) $(chr_LDADD) $(LIBS)
+dll$(EXEEXT): $(dll_OBJECTS) $(dll_DEPENDENCIES) 
+	@rm -f dll$(EXEEXT)
+	$(LINK) $(dll_OBJECTS) $(dll_LDADD) $(LIBS)
 fio$(EXEEXT): $(fio_OBJECTS) $(fio_DEPENDENCIES) 
 	@rm -f fio$(EXEEXT)
 	$(LINK) $(fio_OBJECTS) $(fio_LDADD) $(LIBS)
@@ -416,6 +424,7 @@ distclean-compile:
 	-rm -f *.tab.c
 
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/chr.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/dll.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fio.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/fma.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/htb.Po@am__quote@
diff --git a/qse/samples/cmn/dll.c b/qse/samples/cmn/dll.c
new file mode 100644
index 00000000..315a442d
--- /dev/null
+++ b/qse/samples/cmn/dll.c
@@ -0,0 +1,165 @@
+#include <qse/cmn/mem.h>
+#include <qse/cmn/str.h>
+#include <qse/cmn/dll.h>
+#include <qse/cmn/stdio.h>
+
+
+#define R(f) \
+	do { \
+		qse_printf (QSE_T("== %s ==\n"), QSE_T(#f)); \
+		if (f() == -1) return -1; \
+	} while (0)
+
+static qse_dll_walk_t walk_dll (qse_dll_t* dll, qse_dll_node_t* n, void* arg)
+{
+	qse_printf (QSE_T("[%.*s]\n"), (int)QSE_DLL_DLEN(n), QSE_DLL_DPTR(n));
+	return QSE_DLL_WALK_FORWARD;
+}
+
+static qse_dll_walk_t rwalk_dll (qse_dll_t* dll, qse_dll_node_t* n, void* arg)
+{
+	qse_printf (QSE_T("[%.*s]\n"), (int)QSE_DLL_DLEN(n), QSE_DLL_DPTR(n));
+	return QSE_DLL_WALK_BACKWARD;
+}
+
+static int test1 ()
+{
+	qse_dll_t* s1;
+	qse_dll_node_t* p;
+	qse_char_t* x[] =
+	{
+		QSE_T("this is so good"),
+		QSE_T("what the hack"),
+		QSE_T("do you like it?")
+	};
+	int i;
+
+	s1 = qse_dll_open (QSE_MMGR_GETDFL(), 0);	
+	if (s1 == QSE_NULL)
+	{
+		qse_printf (QSE_T("cannot open a string\n"));
+		return -1;
+	}
+
+	qse_dll_setcopier (s1, QSE_DLL_COPIER_INLINE);
+	qse_dll_setscale (s1, QSE_SIZEOF(qse_char_t));
+
+	for (i = 0; i < QSE_COUNTOF(x); i++)
+	{
+		qse_dll_pushtail (s1, x[i], qse_strlen(x[i]));
+	}
+	qse_printf (QSE_T("s1 holding [%d] nodes\n"), QSE_DLL_SIZE(s1));
+	qse_dll_walk (s1, walk_dll, QSE_NULL);
+		
+
+	p = qse_dll_search (s1, QSE_NULL, x[0], qse_strlen(x[0]));
+	if (p != QSE_NULL)
+	{
+		qse_dll_delete (s1, p);
+	}
+	qse_printf (QSE_T("s1 holding [%d] nodes\n"), QSE_DLL_SIZE(s1));
+	qse_dll_walk (s1, walk_dll, QSE_NULL);
+
+	qse_dll_close (s1);
+	return 0;
+}
+
+static int test2 ()
+{
+	qse_dll_t* s1;
+	qse_dll_node_t* p;
+	qse_char_t* x[] =
+	{
+		QSE_T("this is so good"),
+		QSE_T("what the hack"),
+		QSE_T("do you like it?")
+	};
+	int i;
+
+	s1 = qse_dll_open (QSE_MMGR_GETDFL(), 0);	
+	if (s1 == QSE_NULL)
+	{
+		qse_printf (QSE_T("cannot open a string\n"));
+		return -1;
+	}
+
+	qse_dll_setcopier (s1, QSE_DLL_COPIER_INLINE);
+	qse_dll_setscale (s1, QSE_SIZEOF(qse_char_t));
+
+	for (i = 0; i < QSE_COUNTOF(x); i++)
+	{
+		qse_dll_pushtail (s1, x[i], qse_strlen(x[i]));
+	}
+	qse_printf (QSE_T("s1 holding [%d] nodes\n"), QSE_DLL_SIZE(s1));
+	qse_dll_rwalk (s1, rwalk_dll, QSE_NULL);
+		
+
+	p = qse_dll_search (s1, QSE_NULL, x[0], qse_strlen(x[0]));
+	if (p != QSE_NULL)
+	{
+		qse_dll_delete (s1, p);
+	}
+	qse_printf (QSE_T("s1 holding [%d] nodes\n"), QSE_DLL_SIZE(s1));
+	qse_dll_rwalk (s1, rwalk_dll, QSE_NULL);
+
+	qse_dll_close (s1);
+	return 0;
+}
+
+typedef struct item_t item_t;
+struct item_t
+{
+	int a;
+	int b;
+};
+QSE_DLL_DEFINE_SIMPLE (item_t);
+
+static int test3 ()
+{
+	qse_size_t n;
+	QSE_DLL_TYPE(item_t) ii;
+	QSE_DLL_NODE_TYPE(item_t) x[30];
+	QSE_DLL_NODE_TYPE(item_t)* p;
+
+	QSE_DLL_INIT(&ii);
+
+	for (n = 0; n < QSE_COUNTOF(x); n++)
+	{
+		x[n].data.a = n;
+		x[n].data.b = n * 2;
+	}
+
+	for (n = 0; n < QSE_COUNTOF(x)/2; n++)
+	{
+		QSE_DLL_ADDHEAD (&ii, &x[n]);
+	}
+
+	for (; n < QSE_COUNTOF(x); n++)
+	{
+		QSE_DLL_ADDTAIL (&ii, &x[n]);
+	}
+
+	qse_printf (QSE_T("total %d items\n"), (int)QSE_DLL_SIZE (&ii));
+	for (p = QSE_DLL_HEAD(&ii); QSE_DLL_ISMEMBER(&ii,p); p = p->next)
+	{
+		qse_printf (QSE_T("%d %d\n"), p->data.a, p->data.b);
+	}
+
+	QSE_DLL_UNCHAIN (&ii, QSE_DLL_TAIL(&ii)->prev);
+	QSE_DLL_DELHEAD (&ii);
+	qse_printf (QSE_T("total %d items. printing in reverse\n"), (int)QSE_DLL_SIZE (&ii));
+	for (p = QSE_DLL_TAIL(&ii); QSE_DLL_ISMEMBER(&ii,p); p = p->prev)
+	{
+		qse_printf (QSE_T("%d %d\n"), p->data.a, p->data.b);
+	}
+	QSE_DLL_FINI (&ii);
+	return 0;
+}
+
+int main ()
+{
+	R (test1);
+	R (test2);
+	R (test3);
+	return 0;
+}