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