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khash: update to klib f28c067
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Edward Thomson
Edward Thomson
parent
190b76a698
commit
1ad48c8a08
57
src/khash.h
57
src/khash.h
@ -46,6 +46,19 @@ int main() {
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*/
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/*
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2013-05-02 (0.2.8):
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* Use quadratic probing. When the capacity is power of 2, stepping function
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i*(i+1)/2 guarantees to traverse each bucket. It is better than double
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hashing on cache performance and is more robust than linear probing.
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In theory, double hashing should be more robust than quadratic probing.
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However, my implementation is probably not for large hash tables, because
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the second hash function is closely tied to the first hash function,
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which reduce the effectiveness of double hashing.
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Reference: http://research.cs.vt.edu/AVresearch/hashing/quadratic.php
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2011-12-29 (0.2.7):
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* Minor code clean up; no actual effect.
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@ -110,13 +123,13 @@ int main() {
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Generic hash table library.
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*/
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#define AC_VERSION_KHASH_H "0.2.6"
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#define AC_VERSION_KHASH_H "0.2.8"
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#include <stdlib.h>
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#include <string.h>
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#include <limits.h>
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/* compipler specific configuration */
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/* compiler specific configuration */
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#if UINT_MAX == 0xffffffffu
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typedef unsigned int khint32_t;
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@ -130,11 +143,13 @@ typedef unsigned long khint64_t;
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typedef unsigned long long khint64_t;
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#endif
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#ifndef kh_inline
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#ifdef _MSC_VER
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#define kh_inline __inline
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#else
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#define kh_inline inline
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#endif
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#endif /* kh_inline */
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typedef khint32_t khint_t;
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typedef khint_t khiter_t;
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@ -147,12 +162,6 @@ typedef khint_t khiter_t;
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#define __ac_set_isboth_false(flag, i) (flag[i>>4]&=~(3ul<<((i&0xfU)<<1)))
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#define __ac_set_isdel_true(flag, i) (flag[i>>4]|=1ul<<((i&0xfU)<<1))
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#ifdef KHASH_LINEAR
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#define __ac_inc(k, m) 1
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#else
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#define __ac_inc(k, m) (((k)>>3 ^ (k)<<3) | 1) & (m)
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#endif
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#define __ac_fsize(m) ((m) < 16? 1 : (m)>>4)
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#ifndef kroundup32
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@ -175,7 +184,7 @@ typedef khint_t khiter_t;
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static const double __ac_HASH_UPPER = 0.77;
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#define __KHASH_TYPE(name, khkey_t, khval_t) \
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typedef struct { \
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typedef struct kh_##name##_s { \
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khint_t n_buckets, size, n_occupied, upper_bound; \
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khint32_t *flags; \
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khkey_t *keys; \
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@ -213,19 +222,19 @@ static const double __ac_HASH_UPPER = 0.77;
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SCOPE khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key) \
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{ \
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if (h->n_buckets) { \
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khint_t inc, k, i, last, mask; \
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khint_t k, i, last, mask, step = 0; \
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mask = h->n_buckets - 1; \
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k = __hash_func(key); i = k & mask; \
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inc = __ac_inc(k, mask); last = i; /* inc==1 for linear probing */ \
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last = i; \
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while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
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i = (i + inc) & mask; \
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i = (i + (++step)) & mask; \
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if (i == last) return h->n_buckets; \
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} \
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return __ac_iseither(h->flags, i)? h->n_buckets : i; \
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} else return 0; \
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} \
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SCOPE int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
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{ /* This function uses 0.25*n_bucktes bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
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{ /* This function uses 0.25*n_buckets bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
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khint32_t *new_flags = 0; \
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khint_t j = 1; \
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{ \
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@ -238,11 +247,11 @@ static const double __ac_HASH_UPPER = 0.77;
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memset(new_flags, 0xaa, __ac_fsize(new_n_buckets) * sizeof(khint32_t)); \
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if (h->n_buckets < new_n_buckets) { /* expand */ \
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khkey_t *new_keys = (khkey_t*)krealloc((void *)h->keys, new_n_buckets * sizeof(khkey_t)); \
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if (!new_keys) return -1; \
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if (!new_keys) { kfree(new_flags); return -1; } \
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h->keys = new_keys; \
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if (kh_is_map) { \
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khval_t *new_vals = (khval_t*)krealloc((void *)h->vals, new_n_buckets * sizeof(khval_t)); \
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if (!new_vals) return -1; \
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if (!new_vals) { kfree(new_flags); return -1; } \
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h->vals = new_vals; \
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} \
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} /* otherwise shrink */ \
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@ -258,11 +267,10 @@ static const double __ac_HASH_UPPER = 0.77;
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if (kh_is_map) val = h->vals[j]; \
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__ac_set_isdel_true(h->flags, j); \
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while (1) { /* kick-out process; sort of like in Cuckoo hashing */ \
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khint_t inc, k, i; \
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khint_t k, i, step = 0; \
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k = __hash_func(key); \
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i = k & new_mask; \
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inc = __ac_inc(k, new_mask); \
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while (!__ac_isempty(new_flags, i)) i = (i + inc) & new_mask; \
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while (!__ac_isempty(new_flags, i)) i = (i + (++step)) & new_mask; \
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__ac_set_isempty_false(new_flags, i); \
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if (i < h->n_buckets && __ac_iseither(h->flags, i) == 0) { /* kick out the existing element */ \
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{ khkey_t tmp = h->keys[i]; h->keys[i] = key; key = tmp; } \
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@ -301,14 +309,14 @@ static const double __ac_HASH_UPPER = 0.77;
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} \
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} /* TODO: to implement automatically shrinking; resize() already support shrinking */ \
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{ \
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khint_t inc, k, i, site, last, mask = h->n_buckets - 1; \
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khint_t k, i, site, last, mask = h->n_buckets - 1, step = 0; \
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x = site = h->n_buckets; k = __hash_func(key); i = k & mask; \
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if (__ac_isempty(h->flags, i)) x = i; /* for speed up */ \
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else { \
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inc = __ac_inc(k, mask); last = i; \
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last = i; \
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while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
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if (__ac_isdel(h->flags, i)) site = i; \
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i = (i + inc) & mask; \
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i = (i + (++step)) & mask; \
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if (i == last) { x = site; break; } \
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} \
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if (x == h->n_buckets) { \
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@ -449,7 +457,8 @@ static kh_inline khint_t __ac_Wang_hash(khint_t key)
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@param name Name of the hash table [symbol]
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@param h Pointer to the hash table [khash_t(name)*]
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@param k Key [type of keys]
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@param r Extra return code: 0 if the key is present in the hash table;
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@param r Extra return code: -1 if the operation failed;
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0 if the key is present in the hash table;
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1 if the bucket is empty (never used); 2 if the element in
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the bucket has been deleted [int*]
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@return Iterator to the inserted element [khint_t]
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@ -461,7 +470,7 @@ static kh_inline khint_t __ac_Wang_hash(khint_t key)
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@param name Name of the hash table [symbol]
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@param h Pointer to the hash table [khash_t(name)*]
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@param k Key [type of keys]
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@return Iterator to the found element, or kh_end(h) is the element is absent [khint_t]
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@return Iterator to the found element, or kh_end(h) if the element is absent [khint_t]
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*/
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#define kh_get(name, h, k) kh_get_##name(h, k)
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@ -607,4 +616,4 @@ typedef const char *kh_cstr_t;
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#define KHASH_MAP_INIT_STR(name, khval_t) \
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KHASH_INIT(name, kh_cstr_t, khval_t, 1, kh_str_hash_func, kh_str_hash_equal)
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#endif /* __AC_KHASH_H */
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#endif /* __AC_KHASH_H */
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