[PATCH] TUI: Expand TABs into spaces

[Eli Zaretskii <eliz at gnu dot org>]

"gdb -tui" relies on the curses library and the underlying terminal
driver to expand TAB characters into spaces.  But ncurses on Windows
doesn't do that, and instead displays an IBM graphics character.

The patches below fix that in the command window and in displaying the
registers.

OK to commit?

2015-01-03  Eli Zaretskii  <eliz@gnu.org>

	* tui/tui-regs.c (tui_register_format): Expand TABs into the
	appropriate number of spaces.

	* tui/tui-io.c (tui_puts, tui_redisplay_readline): Expand TABs
	into the appropriate number of spaces.


--- gdb/tui/tui-io.c~0	2014-10-29 21:45:50.000000000 +0200
+++ gdb/tui/tui-io.c	2015-01-03 11:12:52.187500000 +0200
@@ -179,7 +179,19 @@ tui_puts (const char *string)
       else if (tui_skip_line != 1)
         {
           tui_skip_line = -1;
-          waddch (w, c);
+	  if (c == '\t')
+	    {
+	      int line, col;
+
+	      getyx (w, line, col);
+	      do
+		{
+		  waddch (w, ' ');
+		  col++;
+		} while ((col % 8) != 0);
+	    }
+	  else
+	    waddch (w, c);
         }
       else if (c == '\n')
         tui_skip_line = -1;
@@ -254,6 +266,15 @@ tui_redisplay_readline (void)
           waddch (w, '^');
           waddch (w, CTRL_CHAR (c) ? UNCTRL (c) : '?');
 	}
+      else if (c == '\t')
+	{
+	  getyx (w, line, col);
+	  do
+	    {
+	      waddch (w, ' ');
+	      col++;
+	    } while ((col % 8) != 0);
+	}
       else
 	{
           waddch (w, c);


--- gdb/tui/tui-regs.c~0	2014-10-29 21:45:50.000000000 +0200
+++ gdb/tui/tui-regs.c	2015-01-03 12:52:42.062500000 +0200
@@ -676,8 +676,9 @@ tui_register_format (struct frame_info *
   struct ui_file *stream;
   struct ui_file *old_stdout;
   struct cleanup *cleanups;
-  char *p, *s;
+  char *p, *s, *q;
   char *ret;
+  int n_adjust, col;
 
   pagination_enabled = 0;
   old_stdout = gdb_stdout;
@@ -694,7 +695,47 @@ tui_register_format (struct frame_info *
   if (s && s[1] == 0)
     *s = 0;
 
-  ret = xstrdup (p);
+  /* Expand tabs into spaces.  */
+  /* 1. How many additional characters do we need?  */
+  for (col = n_adjust = 0, s = p; s; )
+    {
+      s = strpbrk (s, "\t");
+      if (s)
+	{
+	  col = (s - p) + n_adjust;
+	  /* Adjustment for the next tab stop, minus one for the TAB
+	     we replace with spaces.  */
+	  n_adjust += 8 - (col % 8) - 1;
+	  s++;
+	}
+    }
+
+  /* Allocate the copy.  */
+  ret = q = xmalloc (strlen (p) + n_adjust + 1);
+
+  /* 2. Copy the original string while replacing TABs with spaces.  */
+  for (col = 0, s = p; s; )
+    {
+      char *s1 = strpbrk (s, "\t");
+      if (s1)
+	{
+	  if (s1 > s)
+	    {
+	      strncpy (q, s, s1 - s);
+	      q += s1 - s;
+	      col += s1 - s;
+	    }
+	  do {
+	    *q++ = ' ';
+	    col++;
+	  } while ((col % 8) != 0);
+	  s1++;
+	}
+      else
+	strcpy (q, s);
+      s = s1;
+    }
+
   do_cleanups (cleanups);
 
   return ret;