import json
import sys
if 'esp' in sys.platform:
    from urandom import getrandbits
else:
    import random

def save_object_to_file(obj, filename):
    with open(filename, 'w', encoding='utf-8') as f:
      f.write(json.dumps(obj))

def load_object_from_file(filename):
    try:
      with open(filename, 'r', encoding='utf-8') as f:
          return json.loads(f.read())
    except Exception as e:
        print('Error opening file: ' + filename)
        print(e)
        return None

def randrange(start, stop=None):
    if 'esp' in sys.platform:
        if start == 1:
            return 0
        if stop is None:
            stop = start
            start = 0
        upper = stop - start
        bits = 0
        pwr2 = 1
        while upper > pwr2:
            pwr2 <<= 1
            bits += 1
        while True:
            r = getrandbits(bits)
            if r < upper:
                break
        return r + start
    else:
        return random.randrange(start)