/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License 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.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

#ifndef OPENAIRINTERFACE_DCI_PAYLOAD_UTILS_H
#define OPENAIRINTERFACE_DCI_PAYLOAD_UTILS_H
#include "nfapi/tests/nr_fapi_test.h"

void printbits(const uint64_t n, const uint8_t numBytesToPrint)
{
  uint64_t i;
  uint8_t counter = 0;
  if (numBytesToPrint == 0) {
    i = 1UL << (sizeof(n) * 8 - 1);
  } else {
    i = 1UL << (numBytesToPrint * 8 - 1);
  }
  while (i > 0) {
    if (n & i)
      printf("1");
    else
      printf("0");
    i >>= 1;
    counter++;
    if (counter % 8 == 0) {
      printf(" ");
    }
  }
}

/*! \brief Drops unwanted bits from a byte array, leaving only a specified number of payload bits
 *
 *  \param payloadSizeBits How many bits the payload is to have, from 1 to 64 (8 * DCI_PAYLOAD_BYTE_LEN)
 *  \param payload[] A uint8_t array containing the payload bytes with random data
 *  \details This function creates a bitmask of payloadSizeBits width to truncate the data in payload[] to only have the specified
 *  number of payload bits\n
 *  For example, a payload of 39 bits needs 5 bytes, but on the last byte, the last bit is unused, this function makes sure that
 *  last bit is set to 0, allowing the payload to be then packed and unpacked and successfully compared with the original payload
 */
void truncate_unwanted_bits(uint8_t payloadSizeBits, uint8_t payload[])
{
  uint8_t payloadSizeBytes = (payloadSizeBits + 7) / 8;
  printf("Original Value:\t");
  uint64_t t = 0;
  memcpy(&t, payload, payloadSizeBytes);
  printbits(t, payloadSizeBytes);
  printf("\n");
  uint64_t bitmask = 1;
  for (int i = 0; i < payloadSizeBits - 1; i++) {
    bitmask = bitmask << 1 | 1;
  }
  printf("Calculated Bitmask:\t");
  printbits(bitmask, payloadSizeBytes);
  printf("\n");
  t = t & bitmask;
  printf("Truncated Value:\t");
  printbits(t, payloadSizeBytes);
  printf("\n");
  memcpy(payload, &t, payloadSizeBytes);
}

/*! \brief Generates a random payload payloadSizeBits long into payload[]
 *
 *  \param payloadSizeBits How many bits the payload is to have, from 1 to 64 (8 * DCI_PAYLOAD_BYTE_LEN)
 *  \param payload[] A uint8_t array to contain the generated payload
 *  \details This function fills a uint8_t array with payloadSizeBits of random data, by first filling however many bytes are needed
 *  to contain payloadSizeBits with random data, and then truncating the excess bits
 */
void generate_payload(uint8_t payloadSizeBits, uint8_t payload[])
{
  for (int i = 0; i < (payloadSizeBits + 7) / 8; ++i) {
    payload[i] = rand8();
  }
  truncate_unwanted_bits(payloadSizeBits, payload);
}

#endif // OPENAIRINTERFACE_DCI_PAYLOAD_UTILS_H