diff --git a/moo/lib/Makefile.am b/moo/lib/Makefile.am
index 4a0a972..693f99b 100644
--- a/moo/lib/Makefile.am
+++ b/moo/lib/Makefile.am
@@ -89,6 +89,7 @@ libmoo_la_SOURCES = \
 	rbt.c \
 	sym.c \
 	utf8.c \
+	utf16.c \
 	utl.c \
 	std.c 
 libmoo_la_CPPFLAGS = $(CPPFLAGS_LIB_COMMON) $(CPPFLAGS_PFMOD)
diff --git a/moo/lib/Makefile.in b/moo/lib/Makefile.in
index 544ec73..57d7a04 100644
--- a/moo/lib/Makefile.in
+++ b/moo/lib/Makefile.in
@@ -173,8 +173,8 @@ am_libmoo_la_OBJECTS = libmoo_la-bigint.lo libmoo_la-comp.lo \
 	libmoo_la-gc.lo libmoo_la-heap.lo libmoo_la-moo.lo \
 	libmoo_la-obj.lo libmoo_la-opt.lo libmoo_la-pf-basic.lo \
 	libmoo_la-pf-sys.lo libmoo_la-pf-utf8.lo libmoo_la-rbt.lo \
-	libmoo_la-sym.lo libmoo_la-utf8.lo libmoo_la-utl.lo \
-	libmoo_la-std.lo
+	libmoo_la-sym.lo libmoo_la-utf8.lo libmoo_la-utf16.lo \
+	libmoo_la-utl.lo libmoo_la-std.lo
 libmoo_la_OBJECTS = $(am_libmoo_la_OBJECTS)
 AM_V_lt = $(am__v_lt_@AM_V@)
 am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
@@ -480,6 +480,7 @@ libmoo_la_SOURCES = \
 	rbt.c \
 	sym.c \
 	utf8.c \
+	utf16.c \
 	utl.c \
 	std.c 
 
@@ -663,6 +664,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_la-rbt.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_la-std.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_la-sym.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_la-utf16.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_la-utf8.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_la-utl.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/moo-main.Po@am__quote@
@@ -825,6 +827,13 @@ libmoo_la-utf8.lo: utf8.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o libmoo_la-utf8.lo `test -f 'utf8.c' || echo '$(srcdir)/'`utf8.c
 
+libmoo_la-utf16.lo: utf16.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT libmoo_la-utf16.lo -MD -MP -MF $(DEPDIR)/libmoo_la-utf16.Tpo -c -o libmoo_la-utf16.lo `test -f 'utf16.c' || echo '$(srcdir)/'`utf16.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libmoo_la-utf16.Tpo $(DEPDIR)/libmoo_la-utf16.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='utf16.c' object='libmoo_la-utf16.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o libmoo_la-utf16.lo `test -f 'utf16.c' || echo '$(srcdir)/'`utf16.c
+
 libmoo_la-utl.lo: utl.c
 @am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT libmoo_la-utl.lo -MD -MP -MF $(DEPDIR)/libmoo_la-utl.Tpo -c -o libmoo_la-utl.lo `test -f 'utl.c' || echo '$(srcdir)/'`utl.c
 @am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libmoo_la-utl.Tpo $(DEPDIR)/libmoo_la-utl.Plo
diff --git a/moo/lib/moo-std.h b/moo/lib/moo-std.h
index 92c0052..a084a0a 100644
--- a/moo/lib/moo-std.h
+++ b/moo/lib/moo-std.h
@@ -17,6 +17,7 @@ struct moo_cfgstd_t
 
 	moo_oow_t memsize;
 	int large_pages;
+	moo_cmgr_t* cmgr;
 
 	union
 	{
diff --git a/moo/lib/moo-utl.h b/moo/lib/moo-utl.h
index 000e83f..264bd26 100644
--- a/moo/lib/moo-utl.h
+++ b/moo/lib/moo-utl.h
@@ -361,6 +361,14 @@ MOO_EXPORT int moo_concatoocharstosbuf (
 );
 
 
+/* ------------------------------------------------------------------------- */
+
+MOO_EXPORT int moo_ucwidth (
+	moo_uch_t uc
+);
+
+/* ------------------------------------------------------------------------- */
+
 #if defined(MOO_OOCH_IS_UCH)
 #	define moo_conv_oocs_to_bcs_with_cmgr(oocs,oocslen,bcs,bcslen,cmgr) moo_conv_ucs_to_bcs_with_cmgr(oocs,oocslen,bcs,bcslen,cmgr)
 #	define moo_conv_oochars_to_bchars_with_cmgr(oocs,oocslen,bcs,bcslen,cmgr) moo_conv_uchars_to_bchars_with_cmgr(oocs,oocslen,bcs,bcslen,cmgr)
@@ -378,7 +386,7 @@ MOO_EXPORT int moo_conv_bcs_to_ucs_with_cmgr (
 	moo_cmgr_t*      cmgr,
 	int              all
 );
-	
+
 MOO_EXPORT int moo_conv_bchars_to_uchars_with_cmgr (
 	const moo_bch_t* bcs,
 	moo_oow_t*       bcslen,
@@ -404,6 +412,8 @@ MOO_EXPORT int moo_conv_uchars_to_bchars_with_cmgr (
 	moo_cmgr_t*      cmgr
 );
 
+/* ------------------------------------------------------------------------- */
+
 MOO_EXPORT moo_cmgr_t* moo_get_utf8_cmgr (
 	void
 );
@@ -503,10 +513,52 @@ MOO_EXPORT moo_oow_t moo_utf8_to_uc (
 	moo_uch_t*       uc
 );
 
-MOO_EXPORT int moo_ucwidth (
-	moo_uch_t uc
+/* ------------------------------------------------------------------------- */
+
+MOO_EXPORT moo_cmgr_t* moo_get_utf16_cmgr (
+	void
 );
 
+MOO_EXPORT int moo_conv_uchars_to_utf16 (
+	const moo_uch_t*    ucs,
+	moo_oow_t*          ucslen,
+	moo_bch_t*          bcs,
+	moo_oow_t*          bcslen
+);
+
+MOO_EXPORT int moo_conv_utf16_to_uchars (
+	const moo_bch_t*   bcs,
+	moo_oow_t*         bcslen,
+	moo_uch_t*         ucs,
+	moo_oow_t*         ucslen
+);
+
+
+MOO_EXPORT int moo_conv_ucstr_to_utf16 (
+	const moo_uch_t*    ucs,
+	moo_oow_t*          ucslen,
+	moo_bch_t*          bcs,
+	moo_oow_t*          bcslen
+);
+
+MOO_EXPORT int moo_conv_utf16_to_ucstr (
+	const moo_bch_t*   bcs,
+	moo_oow_t*         bcslen,
+	moo_uch_t*         ucs,
+	moo_oow_t*         ucslen
+);
+
+MOO_EXPORT moo_oow_t moo_uc_to_utf16 (
+	moo_uch_t    uc,
+	moo_bch_t*   utf16,
+	moo_oow_t    size
+);
+
+MOO_EXPORT moo_oow_t moo_utf16_to_uc (
+	const moo_bch_t* utf16,
+	moo_oow_t        size,
+	moo_uch_t*       uc
+);
 
 /* ------------------------------------------------------------------------- */
 
diff --git a/moo/lib/moo.c b/moo/lib/moo.c
index ecf1912..138f92b 100644
--- a/moo/lib/moo.c
+++ b/moo/lib/moo.c
@@ -26,7 +26,7 @@
 
 #include "moo-prv.h"
 
-moo_t* moo_open (moo_mmgr_t* mmgr, moo_oow_t xtnsize, moo_oow_t heapsize, const moo_vmprim_t* vmprim, moo_errinf_t* errinfo)
+moo_t* moo_open (moo_mmgr_t* mmgr, moo_oow_t xtnsize, moo_oow_t heapsize, moo_cmgr_t* cmgr, const moo_vmprim_t* vmprim, moo_errinf_t* errinfo)
 {
 	moo_t* moo;
 
@@ -36,7 +36,7 @@ moo_t* moo_open (moo_mmgr_t* mmgr, moo_oow_t xtnsize, moo_oow_t heapsize, const
 	moo = (moo_t*)MOO_MMGR_ALLOC(mmgr, MOO_SIZEOF(*moo) + xtnsize);
 	if (moo)
 	{
-		if (moo_init(moo, mmgr, heapsize, vmprim) <= -1)
+		if (moo_init(moo, mmgr, heapsize, cmgr, vmprim) <= -1)
 		{
 			if (errinfo) moo_geterrinf (moo, errinfo);
 			MOO_MMGR_FREE (mmgr, moo);
@@ -96,7 +96,7 @@ static void free_heap (moo_t* moo, void* ptr)
 	MOO_MMGR_FREE(moo->mmgr, ptr);
 }
 
-int moo_init (moo_t* moo, moo_mmgr_t* mmgr, moo_oow_t heapsz, const moo_vmprim_t* vmprim)
+int moo_init (moo_t* moo, moo_mmgr_t* mmgr, moo_oow_t heapsz, moo_cmgr_t* cmgr, const moo_vmprim_t* vmprim)
 {
 	int modtab_inited = 0;
 
@@ -108,7 +108,7 @@ int moo_init (moo_t* moo, moo_mmgr_t* mmgr, moo_oow_t heapsz, const moo_vmprim_t
 
 	MOO_MEMSET (moo, 0, MOO_SIZEOF(*moo));
 	moo->mmgr = mmgr;
-	moo->cmgr = moo_get_utf8_cmgr();
+	moo->cmgr = cmgr;
 	moo->vmprim = *vmprim;
 	if (!moo->vmprim.alloc_heap) moo->vmprim.alloc_heap = alloc_heap;
 	if (!moo->vmprim.free_heap) moo->vmprim.free_heap = free_heap;
@@ -129,7 +129,7 @@ int moo_init (moo_t* moo, moo_mmgr_t* mmgr, moo_oow_t heapsz, const moo_vmprim_t
 	 * routine still function despite some side-effects when
 	 * reallocation fails */
 	/* +1 required for consistency with put_oocs and put_ooch in logfmt.c */
-	moo->log.ptr = moo_allocmem (moo, (moo->log.capa + 1) * MOO_SIZEOF(*moo->log.ptr)); 
+	moo->log.ptr = moo_allocmem(moo, (moo->log.capa + 1) * MOO_SIZEOF(*moo->log.ptr)); 
 	if (!moo->log.ptr) goto oops;
 
 	if (moo_rbt_init (&moo->modtab, moo, MOO_SIZEOF(moo_ooch_t), 1) <= -1) goto oops;
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 0e82aa5..d8e2266 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -1834,6 +1834,7 @@ MOO_EXPORT moo_t* moo_open (
 	moo_mmgr_t*         mmgr,
 	moo_oow_t           xtnsize,
 	moo_oow_t           heapsize,
+	moo_cmgr_t*         cmgr,
 	const moo_vmprim_t* vmprim,
 	moo_errinf_t*       errinfo
 );
@@ -1846,6 +1847,7 @@ MOO_EXPORT int moo_init (
 	moo_t*              moo,
 	moo_mmgr_t*         mmgr,
 	moo_oow_t           heapsize,
+	moo_cmgr_t*         cmgr,
 	const moo_vmprim_t* vmprim
 );
 
diff --git a/moo/lib/pf-utf8.c b/moo/lib/pf-utf8.c
index 43b6d11..1ece9ea 100644
--- a/moo/lib/pf-utf8.c
+++ b/moo/lib/pf-utf8.c
@@ -94,5 +94,6 @@ moo_pfrc_t moo_pf_utf8_to_uc (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
 moo_pfrc_t moo_pf_uc_to_utf8 (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
 {
 	MOO_STACK_SETRET (moo, nargs, moo->_nil);
+	/* TODO: */
 	return MOO_PF_SUCCESS;
 }
diff --git a/moo/lib/std.c b/moo/lib/std.c
index 4bc4b30..ce9c0db 100644
--- a/moo/lib/std.c
+++ b/moo/lib/std.c
@@ -3203,7 +3203,8 @@ moo_t* moo_openstd (moo_oow_t xtnsize, const moo_cfgstd_t* cfg, moo_errinf_t* er
 	vmprim.vm_muxwait = vm_muxwait;
 	vmprim.vm_sleep = vm_sleep;
 
-	moo = moo_open(&sys_mmgr, MOO_SIZEOF(xtn_t) + xtnsize, cfg->memsize, &vmprim, errinfo);
+	moo = moo_open(&sys_mmgr, MOO_SIZEOF(xtn_t) + xtnsize, cfg->memsize,
+	               (cfg->cmgr? cfg->cmgr: moo_get_utf8_cmgr), &vmprim, errinfo);
 	if (!moo) return MOO_NULL;
 
 	xtn = GET_XTN(moo);
diff --git a/moo/lib/utf16.c b/moo/lib/utf16.c
new file mode 100644
index 0000000..1f97ef2
--- /dev/null
+++ b/moo/lib/utf16.c
@@ -0,0 +1,77 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2014-2018 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "moo-prv.h"
+
+/* TODO: handle different endians - UTF16BE or UTF16LE */
+
+moo_oow_t moo_uc_to_utf16 (moo_uch_t uc, moo_bch_t* utf16, moo_oow_t size)
+{
+	moo_uint16_t* u16 = (moo_uint16_t*)utf16;
+
+	if (uc <= 0xFFFF) 
+	{
+		u16[0] = (moo_uint16_t)uc;
+		return 2;
+	}
+#if (MOO_SIZEOF_UCH_T > 2)
+	else if (uc <= 0x10FFFF) 
+	{
+		u16[0] = 0xD800 | (((uc >> 16) & 0x1F) - 1) | (uc >> 10);
+		u16[1] = 0xDC00 | (uc & 0x3FF);
+		return 4;
+	}
+#endif
+
+	return 0; /* illegal character */
+}
+
+moo_oow_t moo_utf16_to_uc (const moo_bch_t* utf16, moo_oow_t size, moo_uch_t* uc)
+{
+	const moo_uint16_t* u16 = (const moo_uint16_t*)utf16;
+
+	if (size < 2) return 0; /* incomplete sequence */
+
+	if (u16[0] <= 0xD7FF || u16[0] >= 0xE000) 
+	{
+		/* BMP - U+0000 - U+D7FF, U+E000 - U+FFFF */
+		*uc = u16[0];
+		return 2;
+	}
+#if (MOO_SIZEOF_UCH_T > 2)
+	else if (u16[0] >= 0xD800 && u16[0] <= 0xDBFF) /* high-surrogate */
+	{
+		if (size < 4) return 0; /* incomplete */
+		if (u16[1] >= 0xDC00 && u16[1] <= 0xDFFF) /* low-surrogate */
+		{
+			*uc = (((u16[0] & 0x3FF) << 10) | (u16[1] & 0x3FF)) + 0x10000;
+			return 4;
+		}
+	}
+#endif
+
+	return 0;
+}
diff --git a/moo/lib/utf8.c b/moo/lib/utf8.c
index c62a4a4..1ca1de4 100644
--- a/moo/lib/utf8.c
+++ b/moo/lib/utf8.c
@@ -178,6 +178,8 @@ moo_oow_t moo_utf8_to_uc (const moo_bch_t* utf8, moo_oow_t size, moo_uch_t* uc)
 }
 
 
+/* ----------------------------------------------------------------------- */
+
 /*
  * See http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c 
  */
diff --git a/moo/lib/utl.c b/moo/lib/utl.c
index de07132..a9e165c 100644
--- a/moo/lib/utl.c
+++ b/moo/lib/utl.c
@@ -731,6 +731,43 @@ int moo_conv_ucstr_to_utf8 (const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t*
 
 /* ----------------------------------------------------------------------- */
 
+static moo_cmgr_t utf16_cmgr =
+{
+	moo_utf16_to_uc,
+	moo_uc_to_utf16
+};
+
+moo_cmgr_t* moo_get_utf16_cmgr (void)
+{
+	return &utf16_cmgr;
+}
+
+int moo_conv_utf16_to_uchars (const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
+{
+	/* the source is length bound */
+	return moo_conv_bchars_to_uchars_with_cmgr(bcs, bcslen, ucs, ucslen, &utf16_cmgr, 0);
+}
+
+int moo_conv_uchars_to_utf16 (const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t* bcs, moo_oow_t* bcslen)
+{
+	/* length bound */
+	return moo_conv_uchars_to_bchars_with_cmgr(ucs, ucslen, bcs, bcslen, &utf16_cmgr);
+}
+
+int moo_conv_utf16_to_ucstr (const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
+{
+	/* null-terminated. */
+	return moo_conv_bcs_to_ucs_with_cmgr(bcs, bcslen, ucs, ucslen, &utf16_cmgr, 0);
+}
+
+int moo_conv_ucstr_to_utf16 (const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t* bcs, moo_oow_t* bcslen)
+{
+	/* null-terminated */
+	return moo_conv_ucs_to_bcs_with_cmgr(ucs, ucslen, bcs, bcslen, &utf16_cmgr);
+}
+
+/* ----------------------------------------------------------------------- */
+
 int moo_convbtouchars (moo_t* moo, const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
 {
 	/* length bound */