}

    /* Set result to channel Id */
    Tcl_SetResult(interp, (char *) Tcl_GetChannelName(chan), TCL_VOLATILE);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Unstack Channel --
 *
 *	This function removes the stacked channel from the top of the
 *	channel stack if it is a digest channel.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Removes transform from channel or sets result to error message.
 *
 *----------------------------------------------------------------------
 */
static int DigestUnstackObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    Tcl_Channel chan;
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE  */
    (void) clientData;

    dprintf("Called");

    /* Validate arg count */
    if (objc != 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "channelId");
	return TCL_ERROR;
    }

    /* Get channel */
    chan = Tcl_GetChannel(interp, Tcl_GetString(objv[1]), &mode);
    if (chan == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }

    /* Make sure to operate on the topmost channel */
    chan = Tcl_GetTopChannel(chan);

    /* Check if digest channel */
    if (Tcl_GetChannelType(chan) != &digestChannelType) {
	Tcl_AppendResult(interp, "bad channel \"", Tcl_GetChannelName(chan),
	    "\": not a digest channel", (char *) NULL);
	Tcl_SetErrorCode(interp, "TLS", "UNSTACK", "CHANNEL", "INVALID", (char *) NULL);
	return TCL_ERROR;
    }

    /* Pop transform from channel */
    return Tcl_UnstackChannel(interp, chan);
}

/*******************************************************************/

/*
 *-------------------------------------------------------------------
 *
 * DigestInstanceObjCmd --
 *

    Tcl_CreateObjCommand(interp, "::tls::hmac", HMACObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::mac", MACObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::md4", MD4ObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::md5", MD5ObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::sha1", SHA1ObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::sha256", SHA256ObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::sha512", SHA512ObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateObjCommand(interp, "::tls::unstack", DigestUnstackObjCmd, (ClientData) NULL, (Tcl_CmdDeleteProc *) NULL);
    return TCL_OK;
}