/
indexes.py
41 lines (33 loc) · 871 Bytes
/
indexes.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
from math import *
def calc(max):
return pow2(max+1)-1
def pow2(n):
return 1<<n
def log2(n):
power = 31
while n and not (n & 0x80000000):
n <<= 1
power -= 1
return power
def findchunk(index, maxexp = 4):
p = int(log(index, 2))
if p <= maxexp:
si = index - pow2(p)
else:
index = index - calc(maxexp) - 1
dist = index / pow2(maxexp)
p = maxexp + 1 + dist
si = index - pow2(maxexp) * dist
return p, si
def findchunk2(index, maxexp = 4):
#maximum index for exponential growth
maxexpi = pow2(maxexp+1) - 1
if index < maxexpi:
p = log2(index + 1)
si = index - pow2(p) + 1
else:
index -= maxexpi
dist = index / pow2(maxexp)
p = maxexp + 1 + dist
si = index - pow2(maxexp) * dist
return p, si