Valgrind pointed out a couple of places where we tried to access before

2007-01-24  Chris Wilson <chris@chris-wilson.co.uk>

	* src/vteaccess.c: (vte_terminal_accessible_text_modified):
		Valgrind pointed out a couple of places where we tried to
		access before the start of the string.


svn path=/trunk/; revision=1516

1 files changed, 20 insertions, 16 deletions

diff --git a/src/vteaccess.c b/src/vteaccess.c
index 4b6db012..097ea5aa 100644
--- a/src/vteaccess.c
+++ b/src/vteaccess.c
@@ -483,8 +483,9 @@ vte_terminal_accessible_text_modified(VteTerminal *terminal, gpointer data)
 	}
 
         /* Check if we just backspaced over a space. */
-	if ((olen == offset) && (old[caret_offset] == ' ') &&
-	    (old_snapshot_caret == (priv->snapshot_caret + 1))) {
+	if ((olen == offset) && 
+			(caret_offset < olen && old[caret_offset] == ' ') &&
+			(old_snapshot_caret == (priv->snapshot_caret + 1))) {
 		glong bsp_olen = caret_offset + 1;
 
                 priv->snapshot_text->str = old;
@@ -498,22 +499,25 @@ vte_terminal_accessible_text_modified(VteTerminal *terminal, gpointer data)
 
 	/* At least one of them had better have more data, right? */
 	if ((offset < olen) || (offset < clen)) {
-		gchar *op, *cp;
 		/* Back up from both end points until we find the *last* point
 		 * where they differed.
-		 * Start by looking at the terminating NUL byte */
-		op = old + olen;
-		cp = current + clen;
-		do {
-			op = g_utf8_prev_char (op);
-			cp = g_utf8_prev_char (cp);
-			if ((op <= old + offset) || (cp <= current + offset)) {
-				break;
-			}
-		} while (g_utf8_get_char (op) == g_utf8_get_char (cp));
-		/* recompute the respective lengths */
-		olen = op - old;
-		clen = cp - current;
+		 */
+		if (olen > offset && clen > offset) {
+			/* Start by looking at the terminating NUL byte */
+			gchar *op = old + olen;
+			gchar *cp = current + clen;
+			do {
+				op = g_utf8_prev_char (op);
+				cp = g_utf8_prev_char (cp);
+				if ((op <= old + offset) ||
+					       	(cp <= current + offset)) {
+					break;
+				}
+			} while (g_utf8_get_char (op) == g_utf8_get_char (cp));
+			/* recompute the respective lengths */
+			olen = op - old;
+			clen = cp - current;
+		}
 		/* At least one of them has to have text the other
 		 * doesn't. */
 		g_assert((clen > offset) || (olen > offset));