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#include "sc25519.h"
#include "index_heap.h"
/* caller's responsibility to ensure hlen>=3 */
void heap_init(unsigned long long *h, unsigned long long hlen, sc25519 *scalars)
{
h[0] = 0;
unsigned long long i=1;
while(i<hlen)
heap_push(h, &i, i, scalars);
}
void heap_extend(unsigned long long *h, unsigned long long oldlen, unsigned long long newlen, sc25519 *scalars)
{
unsigned long long i=oldlen;
while(i<newlen)
heap_push(h, &i, i, scalars);
}
void heap_push(unsigned long long *h, unsigned long long *hlen, unsigned long long elem, sc25519 *scalars)
{
/* Move up towards the root */
/* XXX: Check size of hlen, whether cast to signed value is ok */
signed long long pos = *hlen;
signed long long ppos = (pos-1)/2;
unsigned long long t;
h[*hlen] = elem;
while(pos > 0)
{
/* if(sc25519_lt_vartime(&scalars[h[ppos]], &scalars[h[pos]])) */
if(sc25519_lt(&scalars[h[ppos]], &scalars[h[pos]]))
{
t = h[ppos];
h[ppos] = h[pos];
h[pos] = t;
pos = ppos;
ppos = (pos-1)/2;
}
else break;
}
(*hlen)++;
}
/* Put the largest value in the heap in max1, the second largest in max2 */
void heap_get2max(unsigned long long *h, unsigned long long *max1, unsigned long long *max2, sc25519 *scalars)
{
*max1 = h[0];
*max2 = h[1];
if(sc25519_lt(&scalars[h[1]],&scalars[h[2]]))
*max2 = h[2];
}
/* After the root has been replaced, restore heap property */
/* extern void heap_rootreplaced(unsigned long long *h, unsigned long long hlen, sc25519 *scalars);
*/
/* extern void heap_rootreplaced_shortscalars(unsigned long long *h, unsigned long long hlen, sc25519 *scalars);
*/
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