#include <string.h>
#include <assert.h>
-#define INDEX_BITS ((sizeof(shachain_index_t)) * CHAR_BIT)
-
static void change_bit(unsigned char *arr, size_t index)
{
arr[index / CHAR_BIT] ^= (1 << (index % CHAR_BIT));
static unsigned int count_trailing_zeroes(shachain_index_t index)
{
#if HAVE_BUILTIN_CTZLL
- return index ? (unsigned int)__builtin_ctzll(index) : INDEX_BITS;
+ return index ? (unsigned int)__builtin_ctzll(index) : SHACHAIN_BITS;
#else
unsigned int i;
- for (i = 0; i < INDEX_BITS; i++) {
+ for (i = 0; i < SHACHAIN_BITS; i++) {
if (index & (1ULL << i))
break;
}
derive(0, index, seed, hash);
}
+shachain_index_t shachain_next_index(const struct shachain *chain)
+{
+ return chain->min_index - 1;
+}
+
void shachain_init(struct shachain *chain)
{
chain->num_valid = 0;
- chain->min_index = 0;
+ /* This is 0 in the case where SHACHAIN_BITS is 64. */
+ chain->min_index = (shachain_index_t)((UINT64_MAX >> (64 - SHACHAIN_BITS)) + 1);
}
bool shachain_add_hash(struct shachain *chain,
unsigned int i, pos;
/* You have to insert them in order! */
- assert(index == chain->min_index - 1 ||
- (index == (shachain_index_t)(-1ULL) && chain->num_valid == 0));
+ assert(index == shachain_next_index(chain));
pos = count_trailing_zeroes(index);