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039dc71a7c
Copying the first bytes of a SHA1 is duplicated in six places, however, the implications (the actual value would depend on the endianness of the platform) is documented only once. Add a properly documented API for this. Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
331 lines
13 KiB
C
331 lines
13 KiB
C
/* The MIT License
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Copyright (c) 2008, 2009, 2011 by Attractive Chaos <attractor@live.co.uk>
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#ifndef __AC_KHASH_H
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#define __AC_KHASH_H
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#define AC_VERSION_KHASH_H "0.2.8"
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typedef uint32_t khint32_t;
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typedef uint64_t khint64_t;
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typedef khint32_t khint_t;
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typedef khint_t khiter_t;
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#define __ac_isempty(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&2)
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#define __ac_isdel(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&1)
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#define __ac_iseither(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&3)
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#define __ac_set_isdel_false(flag, i) (flag[i>>4]&=~(1ul<<((i&0xfU)<<1)))
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#define __ac_set_isempty_false(flag, i) (flag[i>>4]&=~(2ul<<((i&0xfU)<<1)))
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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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#define __ac_fsize(m) ((m) < 16? 1 : (m)>>4)
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#define kroundup32(x) (--(x), (x)|=(x)>>1, (x)|=(x)>>2, (x)|=(x)>>4, (x)|=(x)>>8, (x)|=(x)>>16, ++(x))
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static inline khint_t __ac_X31_hash_string(const char *s)
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{
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khint_t h = (khint_t)*s;
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if (h) for (++s ; *s; ++s) h = (h << 5) - h + (khint_t)*s;
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return h;
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}
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#define kh_str_hash_func(key) __ac_X31_hash_string(key)
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#define kh_str_hash_equal(a, b) (strcmp(a, b) == 0)
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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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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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khval_t *vals; \
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} kh_##name##_t;
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#define __KHASH_PROTOTYPES(name, khkey_t, khval_t) \
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extern kh_##name##_t *kh_init_##name(void); \
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extern void kh_destroy_##name(kh_##name##_t *h); \
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extern void kh_clear_##name(kh_##name##_t *h); \
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extern khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key); \
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extern int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
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extern khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret); \
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extern void kh_del_##name(kh_##name##_t *h, khint_t x);
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#define __KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
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SCOPE kh_##name##_t *kh_init_##name(void) { \
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return (kh_##name##_t*)xcalloc(1, sizeof(kh_##name##_t)); \
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} \
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SCOPE void kh_destroy_##name(kh_##name##_t *h) \
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{ \
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if (h) { \
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free((void *)h->keys); free(h->flags); \
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free((void *)h->vals); \
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free(h); \
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} \
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} \
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SCOPE void kh_clear_##name(kh_##name##_t *h) \
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{ \
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if (h && h->flags) { \
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memset(h->flags, 0xaa, __ac_fsize(h->n_buckets) * sizeof(khint32_t)); \
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h->size = h->n_occupied = 0; \
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} \
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} \
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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 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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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 + (++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_buckets bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
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khint32_t *new_flags = NULL; \
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khint_t j = 1; \
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{ \
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kroundup32(new_n_buckets); \
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if (new_n_buckets < 4) new_n_buckets = 4; \
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if (h->size >= (khint_t)(new_n_buckets * __ac_HASH_UPPER + 0.5)) j = 0; /* requested size is too small */ \
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else { /* hash table size to be changed (shrink or expand); rehash */ \
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new_flags = (khint32_t*)xmalloc(__ac_fsize(new_n_buckets) * sizeof(khint32_t)); \
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if (!new_flags) return -1; \
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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*)xrealloc((void *)h->keys, new_n_buckets * sizeof(khkey_t)); \
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if (!new_keys) 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*)xrealloc((void *)h->vals, new_n_buckets * sizeof(khval_t)); \
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if (!new_vals) return -1; \
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h->vals = new_vals; \
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} \
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} /* otherwise shrink */ \
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} \
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} \
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if (j) { /* rehashing is needed */ \
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for (j = 0; j != h->n_buckets; ++j) { \
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if (__ac_iseither(h->flags, j) == 0) { \
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khkey_t key = h->keys[j]; \
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khval_t val; \
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khint_t new_mask; \
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new_mask = new_n_buckets - 1; \
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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 k, i, step = 0; \
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k = __hash_func(key); \
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i = k & 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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if (kh_is_map) { khval_t tmp = h->vals[i]; h->vals[i] = val; val = tmp; } \
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__ac_set_isdel_true(h->flags, i); /* mark it as deleted in the old hash table */ \
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} else { /* write the element and jump out of the loop */ \
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h->keys[i] = key; \
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if (kh_is_map) h->vals[i] = val; \
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break; \
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} \
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} \
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} \
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} \
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if (h->n_buckets > new_n_buckets) { /* shrink the hash table */ \
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h->keys = (khkey_t*)xrealloc((void *)h->keys, new_n_buckets * sizeof(khkey_t)); \
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if (kh_is_map) h->vals = (khval_t*)xrealloc((void *)h->vals, new_n_buckets * sizeof(khval_t)); \
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} \
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free(h->flags); /* free the working space */ \
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h->flags = new_flags; \
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h->n_buckets = new_n_buckets; \
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h->n_occupied = h->size; \
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h->upper_bound = (khint_t)(h->n_buckets * __ac_HASH_UPPER + 0.5); \
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} \
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return 0; \
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} \
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SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret) \
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{ \
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khint_t x; \
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if (h->n_occupied >= h->upper_bound) { /* update the hash table */ \
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if (h->n_buckets > (h->size<<1)) { \
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if (kh_resize_##name(h, h->n_buckets - 1) < 0) { /* clear "deleted" elements */ \
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*ret = -1; return h->n_buckets; \
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} \
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} else if (kh_resize_##name(h, h->n_buckets + 1) < 0) { /* expand the hash table */ \
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*ret = -1; return h->n_buckets; \
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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 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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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 + (++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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if (__ac_isempty(h->flags, i) && site != h->n_buckets) x = site; \
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else x = i; \
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} \
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} \
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} \
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if (__ac_isempty(h->flags, x)) { /* not present at all */ \
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h->keys[x] = key; \
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__ac_set_isboth_false(h->flags, x); \
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++h->size; ++h->n_occupied; \
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*ret = 1; \
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} else if (__ac_isdel(h->flags, x)) { /* deleted */ \
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h->keys[x] = key; \
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__ac_set_isboth_false(h->flags, x); \
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++h->size; \
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*ret = 2; \
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} else *ret = 0; /* Don't touch h->keys[x] if present and not deleted */ \
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return x; \
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} \
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SCOPE void kh_del_##name(kh_##name##_t *h, khint_t x) \
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{ \
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if (x != h->n_buckets && !__ac_iseither(h->flags, x)) { \
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__ac_set_isdel_true(h->flags, x); \
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--h->size; \
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} \
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}
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#define KHASH_DECLARE(name, khkey_t, khval_t) \
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__KHASH_TYPE(name, khkey_t, khval_t) \
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__KHASH_PROTOTYPES(name, khkey_t, khval_t)
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#define KHASH_INIT2(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
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__KHASH_TYPE(name, khkey_t, khval_t) \
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__KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
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#define KHASH_INIT(name, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
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KHASH_INIT2(name, static inline, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
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/* Other convenient macros... */
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/*! @function
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@abstract Test whether a bucket contains data.
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@param h Pointer to the hash table [khash_t(name)*]
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@param x Iterator to the bucket [khint_t]
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@return 1 if containing data; 0 otherwise [int]
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*/
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#define kh_exist(h, x) (!__ac_iseither((h)->flags, (x)))
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/*! @function
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@abstract Get key given an iterator
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@param h Pointer to the hash table [khash_t(name)*]
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@param x Iterator to the bucket [khint_t]
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@return Key [type of keys]
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*/
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#define kh_key(h, x) ((h)->keys[x])
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/*! @function
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@abstract Get value given an iterator
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@param h Pointer to the hash table [khash_t(name)*]
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@param x Iterator to the bucket [khint_t]
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@return Value [type of values]
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@discussion For hash sets, calling this results in segfault.
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*/
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#define kh_val(h, x) ((h)->vals[x])
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/*! @function
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@abstract Alias of kh_val()
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*/
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#define kh_value(h, x) ((h)->vals[x])
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/*! @function
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@abstract Get the start iterator
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@param h Pointer to the hash table [khash_t(name)*]
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@return The start iterator [khint_t]
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*/
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#define kh_begin(h) (khint_t)(0)
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/*! @function
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@abstract Get the end iterator
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@param h Pointer to the hash table [khash_t(name)*]
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@return The end iterator [khint_t]
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*/
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#define kh_end(h) ((h)->n_buckets)
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/*! @function
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@abstract Get the number of elements in the hash table
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@param h Pointer to the hash table [khash_t(name)*]
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@return Number of elements in the hash table [khint_t]
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*/
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#define kh_size(h) ((h)->size)
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/*! @function
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@abstract Get the number of buckets in the hash table
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@param h Pointer to the hash table [khash_t(name)*]
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@return Number of buckets in the hash table [khint_t]
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*/
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#define kh_n_buckets(h) ((h)->n_buckets)
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/*! @function
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@abstract Iterate over the entries in the hash table
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@param h Pointer to the hash table [khash_t(name)*]
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@param kvar Variable to which key will be assigned
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@param vvar Variable to which value will be assigned
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@param code Block of code to execute
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*/
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#define kh_foreach(h, kvar, vvar, code) { khint_t __i; \
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for (__i = kh_begin(h); __i != kh_end(h); ++__i) { \
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if (!kh_exist(h,__i)) continue; \
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(kvar) = kh_key(h,__i); \
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(vvar) = kh_val(h,__i); \
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code; \
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} }
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/*! @function
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@abstract Iterate over the values in the hash table
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@param h Pointer to the hash table [khash_t(name)*]
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@param vvar Variable to which value will be assigned
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@param code Block of code to execute
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*/
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#define kh_foreach_value(h, vvar, code) { khint_t __i; \
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for (__i = kh_begin(h); __i != kh_end(h); ++__i) { \
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if (!kh_exist(h,__i)) continue; \
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(vvar) = kh_val(h,__i); \
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code; \
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} }
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#define __kh_oid_cmp(a, b) (hashcmp(a, b) == 0)
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KHASH_INIT(sha1, const unsigned char *, void *, 1, sha1hash, __kh_oid_cmp)
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typedef kh_sha1_t khash_sha1;
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KHASH_INIT(sha1_pos, const unsigned char *, int, 1, sha1hash, __kh_oid_cmp)
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typedef kh_sha1_pos_t khash_sha1_pos;
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#endif /* __AC_KHASH_H */
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