jehanne/sys/src/lib/mp/port/mptole.c

30 lines
570 B
C

#include "os.h"
#include <mp.h>
#include "dat.h"
// convert an mpint into a little endian byte array (least significant byte first)
// return number of bytes converted
// if p == nil, allocate and result array
int
mptole(mpint *b, uint8_t *p, uint32_t n, uint8_t **pp)
{
int m;
assert((p == nil) != (pp == nil));
m = (mpsignif(b)+7)/8;
if(m == 0)
m++;
if(p == nil){
n = m;
p = malloc(n);
if(p == nil)
sysfatal("mptole: %r");
setmalloctag(p, getcallerpc());
} else if(n < m)
return -1;
if(pp != nil)
*pp = p;
mptolel(b, p, n);
return m;
}