Fix displaying of wide (CJK) characters for Win32

diff --git a/common/libobjs.mif b/common/libobjs.mif
index a8f9dc6..ec26d72 100644
--- a/common/libobjs.mif
+++ b/common/libobjs.mif
@@ -15,7 +15,7 @@ getch.$(O) getstr.$(O) getyx.$(O) inch.$(O) inchstr.$(O) \
 initscr.$(O) inopts.$(O) insch.$(O) insstr.$(O) instr.$(O) kernel.$(O) \
 keyname.$(O) mouse.$(O) move.$(O) outopts.$(O) overlay.$(O) pad.$(O) \
 panel.$(O) printw.$(O) refresh.$(O) scanw.$(O) scr_dump.$(O) scroll.$(O) \
-slk.$(O) termattr.$(O) touch.$(O) util.$(O) window.$(O) debug.$(O)
+slk.$(O) termattr.$(O) touch.$(O) util.$(O) window.$(O) debug.$(O) wcwidth.$(O)
 
 PDCOBJS = pdcclip.$(O) pdcdisp.$(O) pdcgetsc.$(O) pdckbd.$(O) pdcscrn.$(O) \
 pdcsetsc.$(O) pdcutil.$(O)
diff --git a/curspriv.h b/curspriv.h
index 991b295..6e4ecfc 100644
--- a/curspriv.h
+++ b/curspriv.h
@@ -48,6 +48,11 @@ extern bool pdc_color_started;
 extern unsigned long pdc_key_modifiers;
 extern MOUSE_STATUS pdc_mouse_status;
 
+#ifdef PDC_WIDE
+# include <wchar.h> /* wchar_t */
+int compat_wcwidth(wchar_t ucs);
+#endif
+
 /*----------------------------------------------------------------------*/
 
 /* Platform implementation functions */
diff --git a/pdcurses/addch.c b/pdcurses/addch.c
index 5146871..47e3f90 100644
--- a/pdcurses/addch.c
+++ b/pdcurses/addch.c
@@ -225,25 +225,42 @@ int waddch(WINDOW *win, const chtype ch)
 
         text |= attr;
 
-        /* Only change _firstch/_lastch if the character to be added is
-           different from the character/attribute that is already in
-           that position in the window. */
-
-        if (win->_y[y][x] != text)
+#ifdef PDC_WIDE
+        /* Leave the rest "width - 1" character positions untouched, just jump
+         * over them.  Platform-specific code is expected to do something
+         * similar. */
+        int width = compat_wcwidth(ch & A_CHARTEXT);
+        if (width < 1) {
+            width = 1;
+        }
+        /* XXX: this might result in truncated character, might want to perform
+         *      the check before setting the character. */
+#else
+        int width = 1;
+#endif
+        while (width-- > 0)
         {
-            if (win->_firstch[y] == _NO_CHANGE)
-                win->_firstch[y] = win->_lastch[y] = x;
-            else
-                if (x < win->_firstch[y])
-                    win->_firstch[y] = x;
+            /* Only change _firstch/_lastch if the character to be added is
+               different from the character/attribute that is already in
+               that position in the window. */
+            if (win->_y[y][x] != text)
+            {
+                if (win->_firstch[y] == _NO_CHANGE)
+                    win->_firstch[y] = win->_lastch[y] = x;
                 else
-                    if (x > win->_lastch[y])
-                        win->_lastch[y] = x;
+                    if (x < win->_firstch[y])
+                        win->_firstch[y] = x;
+                    else
+                        if (x > win->_lastch[y])
+                            win->_lastch[y] = x;
 
-            win->_y[y][x] = text;
+                win->_y[y][x] = text;
+            }
+            ++x;
+            text &= ~A_CHARTEXT;
         }
 
-        if (++x >= win->_maxx)
+        if (x >= win->_maxx)
         {
             /* wrap around test */
 
diff --git a/pdcurses/wcwidth.c b/pdcurses/wcwidth.c
new file mode 100644
index 0000000..9d117bf
--- /dev/null
+++ b/pdcurses/wcwidth.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright (C) Markus Kuhn -- 2007-05-26 (Unicode 5.0)
+ * Copyright (C) xaizek      -- 2014       (Adapt for vifm)
+ * Copyright (C) xaizek      -- 2016       (Adapt for pdcurses)
+ *
+ * This is an implementation of wcwidth() and wcswidth() (defined in
+ * IEEE Std 1002.1-2001) for Unicode.
+ *
+ * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html
+ * http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html
+ *
+ * In fixed-width output devices, Latin characters all occupy a single
+ * "cell" position of equal width, whereas ideographic CJK characters
+ * occupy two such cells. Interoperability between terminal-line
+ * applications and (teletype-style) character terminals using the
+ * UTF-8 encoding requires agreement on which character should advance
+ * the cursor by how many cell positions. No established formal
+ * standards exist at present on which Unicode character shall occupy
+ * how many cell positions on character terminals. These routines are
+ * a first attempt of defining such behavior based on simple rules
+ * applied to data provided by the Unicode Consortium.
+ *
+ * For some graphical characters, the Unicode standard explicitly
+ * defines a character-cell width via the definition of the East Asian
+ * FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes.
+ * In all these cases, there is no ambiguity about which width a
+ * terminal shall use. For characters in the East Asian Ambiguous (A)
+ * class, the width choice depends purely on a preference of backward
+ * compatibility with either historic CJK or Western practice.
+ * Choosing single-width for these characters is easy to justify as
+ * the appropriate long-term solution, as the CJK practice of
+ * displaying these characters as double-width comes from historic
+ * implementation simplicity (8-bit encoded characters were displayed
+ * single-width and 16-bit ones double-width, even for Greek,
+ * Cyrillic, etc.) and not any typographic considerations.
+ *
+ * Much less clear is the choice of width for the Not East Asian
+ * (Neutral) class. Existing practice does not dictate a width for any
+ * of these characters. It would nevertheless make sense
+ * typographically to allocate two character cells to characters such
+ * as for instance EM SPACE or VOLUME INTEGRAL, which cannot be
+ * represented adequately with a single-width glyph. The following
+ * routines at present merely assign a single-cell width to all
+ * neutral characters, in the interest of simplicity. This is not
+ * entirely satisfactory and should be reconsidered before
+ * establishing a formal standard in this area. At the moment, the
+ * decision which Not East Asian (Neutral) characters should be
+ * represented by double-width glyphs cannot yet be answered by
+ * applying a simple rule from the Unicode database content. Setting
+ * up a proper standard for the behavior of UTF-8 character terminals
+ * will require a careful analysis not only of each Unicode character,
+ * but also of each presentation form, something the author of these
+ * routines has avoided to do so far.
+ *
+ * http://www.unicode.org/unicode/reports/tr11/
+ *
+ * Permission to use, copy, modify, and distribute this software
+ * for any purpose and without fee is hereby granted. The author
+ * disclaims all warranties with regard to this software.
+ *
+ * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
+ */
+
+#ifdef PDC_WIDE
+
+#include <curspriv.h>
+
+#include <wchar.h> /* wchar_t */
+
+typedef struct
+{
+	int first;
+	int last;
+}
+interval;
+
+static int bisearch(wchar_t ucs, const interval *table, int max);
+
+/* The following two functions define the column width of an ISO 10646
+ * character as follows:
+ *  - The null character (U+0000) has a column width of 0.
+ *  - Other C0/C1 control characters and DEL will lead to a return
+ *    value of -1.
+ *  - Non-spacing and enclosing combining characters (general
+ *    category code Mn or Me in the Unicode database) have a
+ *    column width of 0.
+ *  - SOFT HYPHEN (U+00AD) has a column width of 1.
+ *  - Other format characters (general category code Cf in the Unicode
+ *    database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
+ *  - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
+ *    have a column width of 0.
+ *  - Spacing characters in the East Asian Wide (W) or East Asian
+ *    Full-width (F) category as defined in Unicode Technical
+ *    Report #11 have a column width of 2.
+ *  - All remaining characters (including all printable
+ *    ISO 8859-1 and WGL4 characters, Unicode control characters,
+ *    etc.) have a column width of 1.
+ * This implementation assumes that wchar_t characters are encoded
+ * in ISO 10646.
+ */
+int
+compat_wcwidth(wchar_t ucs)
+{
+	/* Sorted list of non-overlapping intervals of non-spacing characters
+	 * generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c". */
+	static const interval combining[] =
+	{
+		{ 0x0300, 0x036F }, { 0x0483, 0x0486 }, { 0x0488, 0x0489 },
+		{ 0x0591, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
+		{ 0x05C4, 0x05C5 }, { 0x05C7, 0x05C7 }, { 0x0600, 0x0603 },
+		{ 0x0610, 0x0615 }, { 0x064B, 0x065E }, { 0x0670, 0x0670 },
+		{ 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
+		{ 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
+		{ 0x07A6, 0x07B0 }, { 0x07EB, 0x07F3 }, { 0x0901, 0x0902 },
+		{ 0x093C, 0x093C }, { 0x0941, 0x0948 }, { 0x094D, 0x094D },
+		{ 0x0951, 0x0954 }, { 0x0962, 0x0963 }, { 0x0981, 0x0981 },
+		{ 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD },
+		{ 0x09E2, 0x09E3 }, { 0x0A01, 0x0A02 }, { 0x0A3C, 0x0A3C },
+		{ 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D },
+		{ 0x0A70, 0x0A71 }, { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC },
+		{ 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD },
+		{ 0x0AE2, 0x0AE3 }, { 0x0B01, 0x0B01 }, { 0x0B3C, 0x0B3C },
+		{ 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 }, { 0x0B4D, 0x0B4D },
+		{ 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 }, { 0x0BC0, 0x0BC0 },
+		{ 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 }, { 0x0C46, 0x0C48 },
+		{ 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 }, { 0x0CBC, 0x0CBC },
+		{ 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD },
+		{ 0x0CE2, 0x0CE3 }, { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D },
+		{ 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 },
+		{ 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E },
+		{ 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC },
+		{ 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 },
+		{ 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E },
+		{ 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 },
+		{ 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 },
+		{ 0x1032, 0x1032 }, { 0x1036, 0x1037 }, { 0x1039, 0x1039 },
+		{ 0x1058, 0x1059 }, { 0x1160, 0x11FF }, { 0x135F, 0x135F },
+		{ 0x1712, 0x1714 }, { 0x1732, 0x1734 }, { 0x1752, 0x1753 },
+		{ 0x1772, 0x1773 }, { 0x17B4, 0x17B5 }, { 0x17B7, 0x17BD },
+		{ 0x17C6, 0x17C6 }, { 0x17C9, 0x17D3 }, { 0x17DD, 0x17DD },
+		{ 0x180B, 0x180D }, { 0x18A9, 0x18A9 }, { 0x1920, 0x1922 },
+		{ 0x1927, 0x1928 }, { 0x1932, 0x1932 }, { 0x1939, 0x193B },
+		{ 0x1A17, 0x1A18 }, { 0x1B00, 0x1B03 }, { 0x1B34, 0x1B34 },
+		{ 0x1B36, 0x1B3A }, { 0x1B3C, 0x1B3C }, { 0x1B42, 0x1B42 },
+		{ 0x1B6B, 0x1B73 }, { 0x1DC0, 0x1DCA }, { 0x1DFE, 0x1DFF },
+		{ 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x2060, 0x2063 },
+		{ 0x206A, 0x206F }, { 0x20D0, 0x20EF }, { 0x302A, 0x302F },
+		{ 0x3099, 0x309A }, { 0xA806, 0xA806 }, { 0xA80B, 0xA80B },
+		{ 0xA825, 0xA826 }, { 0xFB1E, 0xFB1E }, { 0xFE00, 0xFE0F },
+		{ 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF }, { 0xFFF9, 0xFFFB },
+		{ 0x10A01, 0x10A03 }, { 0x10A05, 0x10A06 }, { 0x10A0C, 0x10A0F },
+		{ 0x10A38, 0x10A3A }, { 0x10A3F, 0x10A3F }, { 0x1D167, 0x1D169 },
+		{ 0x1D173, 0x1D182 }, { 0x1D185, 0x1D18B }, { 0x1D1AA, 0x1D1AD },
+		{ 0x1D242, 0x1D244 }, { 0xE0001, 0xE0001 }, { 0xE0020, 0xE007F },
+		{ 0xE0100, 0xE01EF }
+	};
+
+	/* Test for 8-bit control characters. */
+	if(ucs == 0)
+	{
+		return 0;
+	}
+	if(ucs < 32 || (ucs >= 0x7f && ucs < 0xa0))
+	{
+		return -1;
+	}
+
+	/* Binary search in table of non-spacing characters. */
+	if(bisearch(ucs, combining, sizeof(combining)/sizeof(combining[0]) - 1))
+	{
+		return 0;
+	}
+
+	/* If we arrive here, ucs is not a combining or C0/C1 control character. */
+
+	return 1 +
+	  (ucs >= 0x1100 &&
+	   (ucs <= 0x115f ||                    /* Hangul Jamo init. consonants */
+	    ucs == 0x2329 || ucs == 0x232a ||
+	    (ucs >= 0x2e80 && ucs <= 0xa4cf &&
+	     ucs != 0x303f) ||                  /* CJK ... Yi */
+	    (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */
+	    (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */
+	    (ucs >= 0xfe10 && ucs <= 0xfe19) || /* Vertical forms */
+	    (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */
+	    (ucs >= 0xff00 && ucs <= 0xff60) || /* Fullwidth Forms */
+	    (ucs >= 0xffe0 && ucs <= 0xffe6) ||
+	    (ucs >= 0x20000 && ucs <= 0x2fffd) ||
+	    (ucs >= 0x30000 && ucs <= 0x3fffd)));
+}
+
+/* Auxiliary function for binary search in interval table. */
+static int
+bisearch(wchar_t ucs, const interval *table, int max)
+{
+	int min;
+
+	if(ucs < table[0].first || ucs > table[max].last)
+	{
+		return 0;
+	}
+
+	min = 0;
+	while(max >= min)
+	{
+		const int mid = (min + max)/2;
+		if(ucs > table[mid].last)
+		{
+			min = mid + 1;
+		}
+		else if(ucs < table[mid].first)
+		{
+			max = mid - 1;
+		}
+		else
+		{
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+#endif