Added function register_duplicate(). Fixed possible segfault in register_get_string().

git-svn-id: https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk@108 b68d4a1b-bc3d-0410-92ed-d4ac073336b7

include/jtag/register.h

@@ -32,6 +32,7 @@ typedef struct tap_register {
 } tap_register;
 
 tap_register *register_alloc( int len );
+tap_register *register_duplicate( tap_register *tr );
 void register_free( tap_register *tr );
 tap_register *register_fill( tap_register *tr, int val );
 const char *register_get_string( tap_register *tr );

jtag/src/tap/register.c

@@ -58,6 +58,15 @@ register_alloc( int len )
 	return tr;
 }
 
+tap_register *
+register_duplicate( tap_register *tr )
+{
+ 	if (!tr)
+		return	NULL;
+
+	return register_init( register_alloc( tr->len ), register_get_string( tr ) );
+}
+
 void
 register_free( tap_register *tr )
 {
@@ -80,12 +89,13 @@ register_fill( tap_register *tr, int val )
 const char *
 register_get_string( tap_register *tr )
 {
-	if (tr) {
-		int i;
+	int i;
 
-		for (i = 0; i < tr->len; i++)
-			tr->string[tr->len - 1 - i] = (tr->data[i] & 1) ? '1' : '0';
-	}
+	if (!tr)
+		return NULL;
+
+	for (i = 0; i < tr->len; i++)
+		tr->string[tr->len - 1 - i] = (tr->data[i] & 1) ? '1' : '0';
 
 	return tr->string;
 }