/*
 * Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use
 * this file except in compliance with the License. A copy of the License is
 * located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing permissions and
 * limitations under the License.
 */

 /* 
 * File contains helper functions to reduce code bloat due to common subroutines. 
 */

module helper_functions where 

import type_def


//Helper function to update the state of the session only. 
advanceStateOnly : session_c_t -> state_size_t -> session_c_t
advanceStateOnly session_old new_state = {
                                        output_size_estimate = session_old.output_size_estimate,
                                        input_size_estimate = session_old.input_size_estimate,
                                        header_size = session_old.header_size,
                                        state = new_state,
                                        mode = session_old.mode,
                                        precise_size = session_old.precise_size,
                                        data_so_far = session_old.data_so_far,
                                        frame_size = session_old.frame_size,
                                        precise_size_known = session_old.precise_size_known,
                                        frame_seqno = session_old.frame_seqno, 
                                        alg_prop = session_old.alg_prop,
                                        header = session_old.header
                                        }

//Helper function to update the input and output size estimates only. 
updateOutputInputEstimates : session_c_t -> size_bits_t -> size_bits_t -> session_c_t
updateOutputInputEstimates session_old output_est input_est = {
                                                                output_size_estimate = output_est,
                                                                input_size_estimate = input_est,
                                                                header_size = session_old.header_size,
                                                                state = session_old.state,
                                                                mode = session_old.mode,
                                                                precise_size = session_old.precise_size,
                                                                data_so_far = session_old.data_so_far,
                                                                frame_size = session_old.frame_size,
                                                                precise_size_known = session_old.precise_size_known,
                                                                frame_seqno = session_old.frame_seqno, 
                                                                alg_prop = session_old.alg_prop,
                                                                header = session_old.header
                                                                }


//Helper function to update the frame_seqno of the session only. 
incrementFrameSeqno : session_c_t -> session_c_t
incrementFrameSeqno session_old = {
                                output_size_estimate = session_old.output_size_estimate,
                                input_size_estimate = session_old.input_size_estimate,
                                header_size = session_old.header_size,
                                state = session_old.state,
                                mode = session_old.mode,
                                precise_size = session_old.precise_size,
                                data_so_far = session_old.data_so_far,
                                frame_size = session_old.frame_size,
                                precise_size_known = session_old.precise_size_known,
                                frame_seqno = session_old.frame_seqno + 1, 
                                alg_prop = session_old.alg_prop,
                                header = session_old.header
                                  }


//Helper function to changed only the session of the state_t to a new state.        
advanceSessionByStateOnly : state_t -> state_size_t -> state_t
advanceSessionByStateOnly state_old new_state = {
                                                sess = advanceStateOnly state_old.sess new_state,
                                                output_buffer = state_old.output_buffer, 
                                                input_buffer = state_old.input_buffer
                                                }