141 lines
9.5 KiB
PHP
141 lines
9.5 KiB
PHP
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//-*- mode:c -*-
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/*
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include this file and call HTIMPL to generate an implementation
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*/
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#define hash_size(h) ((h)->size/2)
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// compute empirical max-probe for a given size
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#define max_probe(size) ((size)>>5)
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#define HTIMPL(HTNAME, HFUNC, EQFUNC) \
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static void **HTNAME##_lookup_bp(htable_t *h, void *key) \
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{ \
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uint_t hv; \
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size_t i, orig, index, iter; \
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size_t newsz, sz = hash_size(h); \
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size_t maxprobe = max_probe(sz); \
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void **tab = h->table; \
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void **ol; \
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\
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hv = HFUNC((uptrint_t)key); \
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retry_bp: \
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iter = 0; \
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index = (index_t)(hv & (sz-1)) * 2; \
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sz *= 2; \
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orig = index; \
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\
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do { \
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if (tab[index+1] == HT_NOTFOUND) { \
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tab[index] = key; \
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return &tab[index+1]; \
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} \
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\
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if (EQFUNC(key, tab[index])) \
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return &tab[index+1]; \
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\
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index = (index+2) & (sz-1); \
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iter++; \
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if (iter > maxprobe) \
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break; \
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} while (index != orig); \
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\
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/* table full */ \
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/* quadruple size, rehash, retry the insert */ \
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/* it's important to grow the table really fast; otherwise we waste */ \
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/* lots of time rehashing all the keys over and over. */ \
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sz = h->size; \
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ol = h->table; \
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if (sz >= (1<<19)) \
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newsz = sz<<1; \
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else \
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newsz = sz<<2; \
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/*printf("trying to allocate %d words.\n", newsz); fflush(stdout);*/ \
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tab = (void**)malloc(newsz*sizeof(void*)); \
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if (tab == NULL) \
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return NULL; \
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for(i=0; i < newsz; i++) \
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tab[i] = HT_NOTFOUND; \
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h->table = tab; \
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h->size = newsz; \
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for(i=0; i < sz; i+=2) { \
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if (ol[i] != HT_NOTFOUND && ol[i+1] != HT_NOTFOUND) { \
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(*HTNAME##_lookup_bp(h, ol[i])) = ol[i+1]; \
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} \
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} \
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free(ol); \
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\
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sz = hash_size(h); \
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maxprobe = max_probe(sz); \
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\
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goto retry_bp; \
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\
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return NULL; \
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} \
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\
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void HTNAME##_put(htable_t *h, void *key, void *val) \
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{ \
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void **bp = HTNAME##_lookup_bp(h, key); \
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\
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*bp = val; \
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} \
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\
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void **HTNAME##_bp(htable_t *h, void *key) \
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{ \
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return HTNAME##_lookup_bp(h, key); \
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} \
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\
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/* returns bp if key is in hash, otherwise NULL */ \
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static void **HTNAME##_peek_bp(htable_t *h, void *key) \
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{ \
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size_t sz = hash_size(h); \
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size_t maxprobe = max_probe(sz); \
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void **tab = h->table; \
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size_t index = (index_t)(HFUNC((uptrint_t)key) & (sz-1)) * 2; \
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sz *= 2; \
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size_t orig = index; \
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size_t iter = 0; \
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\
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do { \
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if (tab[index] == HT_NOTFOUND) \
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return NULL; \
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if (EQFUNC(key, tab[index]) && tab[index+1] != HT_NOTFOUND) \
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return &tab[index+1]; \
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\
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index = (index+2) & (sz-1); \
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iter++; \
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if (iter > maxprobe) \
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break; \
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} while (index != orig); \
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\
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return NULL; \
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} \
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\
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void *HTNAME##_get(htable_t *h, void *key) \
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{ \
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void **bp = HTNAME##_peek_bp(h, key); \
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if (bp == NULL) \
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return HT_NOTFOUND; \
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return *bp; \
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} \
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\
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int HTNAME##_has(htable_t *h, void *key) \
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{ \
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return (HTNAME##_get(h,key) != HT_NOTFOUND); \
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} \
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\
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void HTNAME##_remove(htable_t *h, void *key) \
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{ \
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void **bp = HTNAME##_peek_bp(h, key); \
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if (bp != NULL) \
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*bp = HT_NOTFOUND; \
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} \
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\
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void HTNAME##_adjoin(htable_t *h, void *key, void *val) \
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{ \
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void **bp = HTNAME##_lookup_bp(h, key); \
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if (*bp == HT_NOTFOUND) \
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*bp = val; \
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}
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