--- /dev/null
+#ifndef KHASH_HPP
+#define KHASH_HPP
+
+#include <memory>
+#include <functional>
+#include <cstdlib> // for malloc() etc
+#include <cstring> // for memset()
+
+#include <stdint.h> // for uint32_t
+
+namespace klib {
+
+#ifndef kroundup32 // FIXME: doesn't work for 64-bit integers
+#define kroundup32(x) (--(x), (x)|=(x)>>1, (x)|=(x)>>2, (x)|=(x)>>4, (x)|=(x)>>8, (x)|=(x)>>16, ++(x))
+#endif
+
+#define __ac_isempty(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&2)
+#define __ac_isdel(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&1)
+#define __ac_isempty(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&2)
+#define __ac_isdel(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&1)
+#define __ac_iseither(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&3)
+#define __ac_set_isdel_false(flag, i) (flag[i>>4]&=~(1ul<<((i&0xfU)<<1)))
+#define __ac_set_isempty_false(flag, i) (flag[i>>4]&=~(2ul<<((i&0xfU)<<1)))
+#define __ac_set_isboth_false(flag, i) (flag[i>>4]&=~(3ul<<((i&0xfU)<<1)))
+#define __ac_set_isdel_true(flag, i) (flag[i>>4]|=1ul<<((i&0xfU)<<1))
+
+#define __ac_fsize(m) ((m) < 16? 1 : (m)>>4)
+
+template<class T, class Hash, class Eq = std::equal_to<T>, typename khint_t = uint32_t>
+class KHash {
+ khint_t n_buckets, count, n_occupied, upper_bound;
+ uint32_t *flags;
+ T *keys;
+public:
+ KHash() : n_buckets(0), count(0), n_occupied(0), upper_bound(0), flags(NULL), keys(NULL) {};
+ ~KHash() { std::free(flags); std::free(keys); };
+ khint_t capacity(void) const { return n_buckets; };
+ khint_t size(void) const { return count; };
+ khint_t begin(void) const { return 0; };
+ khint_t end(void) const { return n_buckets; };
+
+ void exist(khint_t x) const { return !__ac_iseither(flags, x); };
+ T &at(khint_t x) { return keys[x]; };
+
+ khint_t get(const T &key) const {
+ if (n_buckets) {
+ khint_t k, i, last, mask, step = 0;
+ mask = n_buckets - 1;
+ k = Hash()(key); i = k & mask;
+ last = i;
+ while (!__ac_isempty(flags, i) && (__ac_isdel(flags, i) || !Eq()(keys[i], key))) {
+ i = (i + (++step)) & mask;
+ if (i == last) return n_buckets;
+ }
+ return __ac_iseither(flags, i)? n_buckets : i;
+ } else return 0;
+ };
+
+ int resize(khint_t new_n_buckets) {
+ uint32_t *new_flags = 0;
+ khint_t j = 1;
+ {
+ kroundup32(new_n_buckets);
+ if (new_n_buckets < 4) new_n_buckets = 4;
+ if (count >= (new_n_buckets>>1) + (new_n_buckets>>2)) j = 0; /* requested count is too small */
+ else { /* hash table count to be changed (shrink or expand); rehash */
+ new_flags = (uint32_t*)std::malloc(__ac_fsize(new_n_buckets) * sizeof(uint32_t));
+ if (!new_flags) return -1;
+ ::memset(new_flags, 0xaa, __ac_fsize(new_n_buckets) * sizeof(uint32_t));
+ if (n_buckets < new_n_buckets) { /* expand */
+ T *new_keys = (T*)std::realloc((void *)keys, new_n_buckets * sizeof(T));
+ if (!new_keys) { std::free(new_flags); return -1; }
+ keys = new_keys;
+ } /* otherwise shrink */
+ }
+ }
+ if (j) { /* rehashing is needed */
+ for (j = 0; j != n_buckets; ++j) {
+ if (__ac_iseither(flags, j) == 0) {
+ T key = keys[j];
+ khint_t new_mask;
+ new_mask = new_n_buckets - 1;
+ __ac_set_isdel_true(flags, j);
+ while (1) { /* kick-out process; sort of like in Cuckoo hashing */
+ khint_t k, i, step = 0;
+ k = Hash()(key);
+ i = k & new_mask;
+ while (!__ac_isempty(new_flags, i)) i = (i + (++step)) & new_mask;
+ __ac_set_isempty_false(new_flags, i);
+ if (i < n_buckets && __ac_iseither(flags, i) == 0) { /* kick out the existing element */
+ { T tmp = keys[i]; keys[i] = key; key = tmp; }
+ __ac_set_isdel_true(flags, i); /* mark it as deleted in the old hash table */
+ } else { /* write the element and jump out of the loop */
+ keys[i] = key;
+ break;
+ }
+ }
+ }
+ }
+ if (n_buckets > new_n_buckets) /* shrink the hash table */
+ keys = (T*)std::realloc((void *)keys, new_n_buckets * sizeof(T));
+ std::free(flags); /* free the working space */
+ flags = new_flags;
+ n_buckets = new_n_buckets;
+ n_occupied = count;
+ upper_bound = (n_buckets>>1) + (n_buckets>>2);
+ }
+ return 0;
+ };
+
+ khint_t put(const T &key, int *ret) {
+ khint_t x;
+ if (n_occupied >= upper_bound) { /* update the hash table */
+ if (n_buckets > (count<<1)) {
+ if (resize(n_buckets - 1) < 0) { /* clear "deleted" elements */
+ *ret = -1; return n_buckets;
+ }
+ } else if (resize(n_buckets + 1) < 0) { /* expand the hash table */
+ *ret = -1; return n_buckets;
+ }
+ } /* TODO: to implement automatically shrinking; resize() already support shrinking */
+ {
+ khint_t k, i, site, last, mask = n_buckets - 1, step = 0;
+ x = site = n_buckets; k = Hash()(key); i = k & mask;
+ if (__ac_isempty(flags, i)) x = i; /* for speed up */
+ else {
+ last = i;
+ while (!__ac_isempty(flags, i) && (__ac_isdel(flags, i) || !Eq()(keys[i], key))) {
+ if (__ac_isdel(flags, i)) site = i;
+ i = (i + (++step)) & mask;
+ if (i == last) { x = site; break; }
+ }
+ if (x == n_buckets) {
+ if (__ac_isempty(flags, i) && site != n_buckets) x = site;
+ else x = i;
+ }
+ }
+ }
+ if (__ac_isempty(flags, x)) { /* not present at all */
+ keys[x] = key;
+ __ac_set_isboth_false(flags, x);
+ ++count; ++n_occupied;
+ *ret = 1;
+ } else if (__ac_isdel(flags, x)) { /* deleted */
+ keys[x] = key;
+ __ac_set_isboth_false(flags, x);
+ ++count;
+ *ret = 2;
+ } else *ret = 0; /* Don't touch keys[x] if present and not deleted */
+ return x;
+ };
+
+ void del(khint_t x) {
+ if (x != n_buckets && !__ac_iseither(flags, x)) {
+ __ac_set_isdel_true(flags, x);
+ --count;
+ }
+ };
+};
+
+} // end of namespace klib
+
+#endif
projects / klib.git / commitdiff