Use parm_left_cursor and parm_right_cursor for bulk cursor motions.

Fixes #1448

output.cpp

@@ -418,13 +418,6 @@ int writeb(tputs_arg_t b)
     return 0;
 }
 
-int writembs_internal(char *str)
-{
-    CHECK(str, 1);
-
-    return tputs(str,1,&writeb)==ERR?1:0;
-}
-
 int writech(wint_t ch)
 {
     mbstate_t state;
@@ -725,3 +718,20 @@ const wchar_t *output_get_term()
 {
     return current_term.empty() ? L"<unknown>" : current_term.c_str();
 }
+
+void writembs_check(char *mbs, const char *mbs_name, const char *file, long line)
+{
+    if (mbs != NULL)
+    {
+        tputs(mbs, 1, &writeb);
+    }
+    else
+    {
+        debug( 0, _(L"Tried to use terminfo string %s on line %ld of %s, which is undefined in terminal of type \"%ls\". Please report this error to %s"),
+              mbs_name,
+              line,
+              file,
+              output_get_term(),
+              PACKAGE_BUGREPORT);
+    }
+}

output.h

@@ -78,33 +78,8 @@ void set_color(rgb_color_t c, rgb_color_t c2);
 /**
    Write specified multibyte string
  */
-#define writembs( mbs )                         \
+void writembs_check(char *mbs, const char *mbs_name, const char *file, long line);
-        {                                       \
+#define writembs(mbs) writembs_check((mbs), #mbs, __FILE__, __LINE__)
-                char *tmp = mbs;                \
-                if( tmp )        \
-                {          \
-                        writembs_internal( tmp );      \
-                }              \
-                else              \
-                {              \
-                        debug( 0,          \
-             _(L"Tried to use terminfo string %s on line %d of %s, which is undefined in terminal of type \"%ls\". Please report this error to %s"), \
-             #mbs,          \
-             __LINE__,        \
-             __FILE__,        \
-             output_get_term(),      \
-             PACKAGE_BUGREPORT);      \
-    }                                                       \
-  }
-
-
-/**
-   Write a char * narrow string to FD 1, needed for the terminfo
-   strings. This is usually just a wrapper aound tputs, using writeb
-   as the sending function. But a weird bug on PPC Linux means that on
-   this platform, write is instead used directly.
-*/
-int writembs_internal(char *str);
 
 /**
    Write a wide character using the output method specified using output_set_writer().

screen.cpp

@@ -638,18 +638,32 @@ static void s_move(screen_t *s, data_buffer_t *b, int new_x, int new_y)
         x_steps = 0;
     }
 
+    char *multi_str = NULL;
     if (x_steps < 0)
     {
         str = cursor_left;
+        multi_str = parm_left_cursor;
     }
     else
     {
         str = cursor_right;
+        multi_str = parm_right_cursor;
     }
-
+    
-    for (i=0; i<abs(x_steps); i++)
+    // Use the bulk ('multi') output for cursor movement if it is supported and it would be shorter
+    // Note that this is required to avoid some visual glitches in iTerm (#1448)
+    bool use_multi = (multi_str != NULL && multi_str[0] != '\0' && abs(x_steps) * strlen(str) > strlen(multi_str));
+    if (use_multi)
     {
-        writembs(str);
+        char *multi_param = tparm(multi_str, abs(x_steps));
+        writembs(multi_param);
+    }
+    else
+    {
+        for (i=0; i<abs(x_steps); i++)
+        {
+            writembs(str);
+        }
     }