1 files changed, 18 insertions, 1 deletions
diff --git a/newlib/libc/string/wcswidth.c b/newlib/libc/string/wcswidth.c
index 8a9670eb1..6c0efe63f 100644
--- a/newlib/libc/string/wcswidth.c
+++ b/newlib/libc/string/wcswidth.c
@@ -37,6 +37,7 @@ PORTABILITY
 
 #include <_ansi.h>
 #include <wchar.h>
+#include "local.h"
 
 int
 _DEFUN (wcswidth, (pwcs, n),
@@ -48,7 +49,23 @@ _DEFUN (wcswidth, (pwcs, n),
   if (!pwcs || n == 0)
     return 0;
   do {
-    if ((w = wcwidth (*pwcs)) < 0)
+    wint_t wi = *pwcs;
+
+#ifdef _MB_CAPABLE
+  wi = _jp2uc (wi);
+  /* First half of a surrogate pair? */
+  if (sizeof (wchar_t) == 2 && wi >= 0xd800 && wi <= 0xdbff)
+    {
+      wint_t wi2;
+
+      /* Extract second half and check for validity. */
+      if (--n == 0 || (wi2 = _jp2uc (*++pwcs)) < 0xdc00 || wi2 > 0xdfff)
+	return -1;
+      /* Compute actual unicode value to use in call to __wcwidth. */
+      wi = (((wi & 0x3ff) << 10) | (wi2 & 0x3ff)) + 0x10000;
+    }
+#endif /* _MB_CAPABLE */
+    if ((w = __wcwidth (wi)) < 0)
       return -1;
     len += w;
   } while (*pwcs++ && --n > 0);