Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2020 Project CHIP Authors
       4              :  *    Copyright (c) 2013-2017 Nest Labs, Inc.
       5              :  *
       6              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       7              :  *    you may not use this file except in compliance with the License.
       8              :  *    You may obtain a copy of the License at
       9              :  *
      10              :  *        http://www.apache.org/licenses/LICENSE-2.0
      11              :  *
      12              :  *    Unless required by applicable law or agreed to in writing, software
      13              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      14              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      15              :  *    See the License for the specific language governing permissions and
      16              :  *    limitations under the License.
      17              :  */
      18              : 
      19              : /**
      20              :  *    @file
      21              :  *      This file implements utility functions for deriving a fibonacci
      22              :  *      number from an index.
      23              :  *
      24              :  */
      25              : 
      26              : #include <stdint.h>
      27              : #include <stdlib.h>
      28              : 
      29              : #include "FibonacciUtils.h"
      30              : 
      31              : namespace chip {
      32              : 
      33           21 : uint32_t GetFibonacciForIndex(uint32_t inIndex)
      34              : {
      35           21 :     uint32_t retval = 0;
      36           21 :     uint32_t tmp    = 0;
      37              :     uint32_t vals[2];
      38           21 :     uint32_t index = 0;
      39              : 
      40           21 :     vals[0] = 0;
      41           21 :     vals[1] = 1;
      42              : 
      43           21 :     if (inIndex < 2)
      44              :     {
      45           12 :         retval = vals[inIndex];
      46              :     }
      47              :     else
      48              :     {
      49           54 :         for (index = 2; index <= inIndex; index++)
      50              :         {
      51           45 :             tmp = vals[0] + vals[1];
      52              : 
      53           45 :             vals[0] = vals[1];
      54           45 :             vals[1] = tmp;
      55              :         }
      56              : 
      57            9 :         retval = tmp;
      58              :     }
      59              : 
      60           21 :     return retval;
      61              : }
      62              : 
      63              : } // namespace chip