From 564cedb49e758b212e4157df170ff4b729d3ce96 Mon Sep 17 00:00:00 2001
From: Rocco Rutte <pdmef@gmx.net>
Date: Fri, 28 Sep 2007 11:06:43 +0200
Subject: [PATCH] Make mutt_FormatString()'s string truncation multibyte aware

---
 curs_lib.c | 32 ++++++++++++++++++++++++++++++++
 muttlib.c  | 14 +++++++-------
 protos.h   |  1 +
 3 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/curs_lib.c b/curs_lib.c
index 8fdb6816..cb1947ab 100644
--- a/curs_lib.c
+++ b/curs_lib.c
@@ -822,6 +822,38 @@ void mutt_paddstr (int n, const char *s)
     addch (' ');
 }
 
+/* See how many bytes to copy from string so its at most maxlen bytes
+ * long and maxwid columns wide */
+int mutt_wstr_trunc (const char *src, size_t maxlen, size_t maxwid, size_t *width)
+{
+  wchar_t wc;
+  int w = 0, l = 0, cl;
+  size_t cw, n;
+  mbstate_t mbstate;
+
+  if (!src)
+    goto out;
+
+  n = mutt_strlen (src);
+
+  memset (&mbstate, 0, sizeof (mbstate));
+  for (w = 0; n && (cl = mbrtowc (&wc, src, n, &mbstate)); src += cl, n -= cl)
+  {
+    if (cl == (size_t)(-1) || cl == (size_t)(-2))
+      cw = cl = 1;
+    else
+      cw = wcwidth (wc);
+    if (cl + l > maxlen || cw + w > maxwid)
+      break;
+    l += cl;
+    w += cw;
+  }
+out:
+  if (width)
+    *width = w;
+  return l;
+}
+
 /*
  * returns the number of bytes the first (multibyte) character
  * of input consumes:
diff --git a/muttlib.c b/muttlib.c
index ca06d27c..2b7be974 100644
--- a/muttlib.c
+++ b/muttlib.c
@@ -1232,16 +1232,16 @@ void mutt_FormatString (char *dest,		/* output buffer */
 	  else if (soft && pad < 0)
 	  {
 	    /* set wptr and wlen back just enough bytes to make sure buf
-	     * fits on screen, col needs no adjustments as we skip more input
-	     * currently multibyte unaware */
+	     * fits on screen, \0-terminate dest so mutt_wstr_trunc()
+	     * can correctly compute string's length */
 	    if (pad < -wlen)
 	      pad = -wlen;
-	    wlen += pad;
-	    wptr += pad;
+	    *wptr = 0;
+	    wlen = mutt_wstr_trunc (dest, wlen + pad, col + pad, &col);
+	    wptr = dest + wlen;
 	  }
 	  if (len + wlen > destlen)
-	    len = destlen - wlen;
-	  /* copy as much of buf as possible: multibyte unaware */
+	    len = mutt_wstr_trunc (buf, destlen - wlen, COLS - col, NULL);
 	  memcpy (wptr, buf, len);
 	  wptr += len;
 	  wlen += len;
@@ -1304,7 +1304,7 @@ void mutt_FormatString (char *dest,		/* output buffer */
 	}
 	
 	if ((len = mutt_strlen (buf)) + wlen > destlen)
-	  len = (destlen - wlen > 0) ? (destlen - wlen) : 0;
+	  len = mutt_wstr_trunc (buf, destlen - wlen, COLS - col, NULL);
 
 	memcpy (wptr, buf, len);
 	wptr += len;
diff --git a/protos.h b/protos.h
index 210ef6e7..7a156b69 100644
--- a/protos.h
+++ b/protos.h
@@ -355,6 +355,7 @@ int mutt_search_command (int, int);
 int mutt_smtp_send (const ADDRESS *, const ADDRESS *, const ADDRESS *,
                     const ADDRESS *, const char *, int);
 #endif
+int mutt_wstr_trunc (const char *, size_t, size_t, size_t *);
 int mutt_charlen (const char *s, int *);
 int mutt_strwidth (const char *);
 int mutt_compose_menu (HEADER *, char *, size_t, HEADER *);
-- 
2.40.0