132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
// Copyright (c) 2012-2013 The Cryptonote developers
|
|
// Distributed under the MIT/X11 software license, see the accompanying
|
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
#include <alloca.h>
|
|
#include <assert.h>
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
|
|
#include "hash-ops.h"
|
|
|
|
void tree_hash(const char (*hashes)[HASH_SIZE], size_t count, char *root_hash) {
|
|
assert(count > 0);
|
|
if (count == 1) {
|
|
memcpy(root_hash, hashes, HASH_SIZE);
|
|
} else if (count == 2) {
|
|
cn_fast_hash(hashes, 2 * HASH_SIZE, root_hash);
|
|
} else {
|
|
size_t i, j;
|
|
size_t cnt = count - 1;
|
|
char (*ints)[HASH_SIZE];
|
|
for (i = 1; i < sizeof(size_t) << 3; i <<= 1) {
|
|
cnt |= cnt >> i;
|
|
}
|
|
cnt &= ~(cnt >> 1);
|
|
ints = alloca(cnt * HASH_SIZE);
|
|
memcpy(ints, hashes, (2 * cnt - count) * HASH_SIZE);
|
|
for (i = 2 * cnt - count, j = 2 * cnt - count; j < cnt; i += 2, ++j) {
|
|
cn_fast_hash(hashes[i], 2 * HASH_SIZE, ints[j]);
|
|
}
|
|
assert(i == count);
|
|
while (cnt > 2) {
|
|
cnt >>= 1;
|
|
for (i = 0, j = 0; j < cnt; i += 2, ++j) {
|
|
cn_fast_hash(ints[i], 64, ints[j]);
|
|
}
|
|
}
|
|
cn_fast_hash(ints[0], 2 * HASH_SIZE, root_hash);
|
|
}
|
|
}
|
|
|
|
size_t tree_depth(size_t count)
|
|
{
|
|
size_t i;
|
|
size_t depth = 0;
|
|
assert(count > 0);
|
|
for (i = sizeof(size_t) << 2; i > 0; i >>= 1)
|
|
{
|
|
if (count >> i > 0)
|
|
{
|
|
count >>= i;
|
|
depth += i;
|
|
}
|
|
}
|
|
return depth;
|
|
}
|
|
|
|
void tree_branch(const char (*hashes)[HASH_SIZE], size_t count, char (*branch)[HASH_SIZE])
|
|
{
|
|
size_t i, j;
|
|
size_t cnt = 1;
|
|
size_t depth = 0;
|
|
char (*ints)[HASH_SIZE];
|
|
assert(count > 0);
|
|
for (i = sizeof(size_t) << 2; i > 0; i >>= 1)
|
|
{
|
|
if (cnt << i <= count)
|
|
{
|
|
cnt <<= i;
|
|
depth += i;
|
|
}
|
|
}
|
|
assert(cnt == 1ULL << depth);
|
|
assert(depth == tree_depth(count));
|
|
ints = alloca((cnt - 1) * HASH_SIZE);
|
|
memcpy(ints, hashes + 1, (2 * cnt - count - 1) * HASH_SIZE);
|
|
for (i = 2 * cnt - count, j = 2 * cnt - count - 1; j < cnt - 1; i += 2, ++j)
|
|
{
|
|
cn_fast_hash(hashes[i], 2 * HASH_SIZE, ints[j]);
|
|
}
|
|
assert(i == count);
|
|
while (depth > 0)
|
|
{
|
|
assert(cnt == 1ULL << depth);
|
|
cnt >>= 1;
|
|
--depth;
|
|
memcpy(branch[depth], ints[0], HASH_SIZE);
|
|
for (i = 1, j = 0; j < cnt - 1; i += 2, ++j)
|
|
{
|
|
cn_fast_hash(ints[i], 2 * HASH_SIZE, ints[j]);
|
|
}
|
|
}
|
|
}
|
|
|
|
void tree_hash_from_branch(const char (*branch)[HASH_SIZE], size_t depth, const char* leaf, const void* path, char* root_hash)
|
|
{
|
|
if (depth == 0)
|
|
{
|
|
memcpy(root_hash, leaf, HASH_SIZE);
|
|
}
|
|
else
|
|
{
|
|
char buffer[2][HASH_SIZE];
|
|
int from_leaf = 1;
|
|
char *leaf_path, *branch_path;
|
|
while (depth > 0)
|
|
{
|
|
--depth;
|
|
if (path && (((const char*) path)[depth >> 3] & (1 << (depth & 7))) != 0)
|
|
{
|
|
leaf_path = buffer[1];
|
|
branch_path = buffer[0];
|
|
}
|
|
else
|
|
{
|
|
leaf_path = buffer[0];
|
|
branch_path = buffer[1];
|
|
}
|
|
if (from_leaf)
|
|
{
|
|
memcpy(leaf_path, leaf, HASH_SIZE);
|
|
from_leaf = 0;
|
|
}
|
|
else
|
|
{
|
|
cn_fast_hash(buffer, 2 * HASH_SIZE, leaf_path);
|
|
}
|
|
memcpy(branch_path, branch[depth], HASH_SIZE);
|
|
}
|
|
cn_fast_hash(buffer, 2 * HASH_SIZE, root_hash);
|
|
}
|
|
} |