-
Notifications
You must be signed in to change notification settings - Fork 5
/
entropy.c
46 lines (40 loc) · 1.06 KB
/
entropy.c
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
42
43
44
45
46
void main() {
unsigned long long cs[256] = {0};
unsigned long long pops[256] = {0};
unsigned long long expops[256] = {0};
unsigned long long sum = 0;
unsigned char c[2048];
int rv;
int i;
while ((rv = read(0, c, 2048)))
{
for (i = 0; i < rv; i++) {
cs[c[i]]++;
c[i] = ((c[i] & 0xAA) >> 1) + (c[i] & 0x55);
c[i] = ((c[i] & 0xCC) >> 2) + (c[i] & 0x33);
c[i] = ((c[i] & 0xF0) >> 4) + (c[i] & 0x0F);
pops[c[i]]++;
}
sum += rv;
}
printf("total bytes: %llu\n", sum);
for (i = 0; i < 256; i++)
{
float f = (double)cs[i] / (double)sum;
printf("%02x: %1.3f\n", i, f);
}
for (i = 0; i < 256; i++) {
c[i] = i;
c[i] = ((c[i] & 0xAA) >> 1) + (c[i] & 0x55);
c[i] = ((c[i] & 0xCC) >> 2) + (c[i] & 0x33);
c[i] = ((c[i] & 0xF0) >> 4) + (c[i] & 0x0F);
expops[c[i]]++;
}
for (i = 0; i < 9; i++)
{
float f = (double)pops[i] / (double)sum;
float f2 = (double)expops[i] / 256.0;
printf("pop%d: %1.3f, ex %1.3f, norm %1.3f\n", i, f, f2, f/f2);
pops[i] = 0;
}
}