From ab52d02963fcb0aecd8089ddc5cdc4d783092a4b Mon Sep 17 00:00:00 2001
From: Jonathan Clairembault <jonathan@clairembault.fr>
Date: Fri, 23 Nov 2012 09:24:53 +0100
Subject: expand: handle backspace.

---
 toys/posix/expand.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'toys/posix/expand.c')

diff --git a/toys/posix/expand.c b/toys/posix/expand.c
index 739c326d..bbe6fdf1 100644
--- a/toys/posix/expand.c
+++ b/toys/posix/expand.c
@@ -1,6 +1,4 @@
 /* expand.c - expands tabs to space
- *
- * FIXME: handle backspace.
  *
  * Copyright 2012 Jonathan Clairembault <jonathan at clairembault dot fr>
  *
@@ -116,7 +114,10 @@ static void expand_file(int fd, char *name)
         wrlinei += count;
       } else { /* copy input to output */
         wrbuf[wrbufi++] = rdbuf[rdbufi];
-        wrlinei += 1;
+        if (rdbuf[rdbufi] == '\b') /* go back one column on backspace */
+          wrlinei -= !!wrlinei; /* do not go below zero */
+        else
+          wrlinei += 1;
         /* flush expand buffer and reset tablist at newline */
         if (rdbuf[rdbufi] == '\n') {
           writeall(STDOUT_FILENO, wrbuf, wrbufi);
-- 
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