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#include "os.h"
#include <mp.h>
#include "dat.h"
/* convert a big-endian byte array (most significant byte first) to an mpint */
mpint*
betomp(uchar *p, uint n, mpint *b)
{
int m, s;
mpdigit x;
if(b == nil)
b = mpnew(0);
/* dump leading zeros */
while(*p == 0 && n > 1){
p++;
n--;
}
/* get the space */
mpbits(b, n*8);
b->top = DIGITS(n*8);
m = b->top-1;
/* first digit might not be Dbytes long */
s = ((n-1)*8)%Dbits;
x = 0;
for(; n > 0; n--){
x |= ((mpdigit)(*p++)) << s;
s -= 8;
if(s < 0){
b->p[m--] = x;
s = Dbits-8;
x = 0;
}
}
return b;
}
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