| /* Copyright 2002 Christopher Clark */ |
| /* Copyright 2005-2012 Nick Mathewson */ |
| /* Copyright 2009-2012 Niels Provos and Nick Mathewson */ |
| /* See license at end. */ |
| |
| /* Based on ideas by Christopher Clark and interfaces from Niels Provos. */ |
| |
| #ifndef HT_INTERNAL_H_INCLUDED_ |
| #define HT_INTERNAL_H_INCLUDED_ |
| |
| #define HT_HEAD(name, type) \ |
| struct name { \ |
| /* The hash table itself. */ \ |
| struct type **hth_table; \ |
| /* How long is the hash table? */ \ |
| unsigned hth_table_length; \ |
| /* How many elements does the table contain? */ \ |
| unsigned hth_n_entries; \ |
| /* How many elements will we allow in the table before resizing it? */ \ |
| unsigned hth_load_limit; \ |
| /* Position of hth_table_length in the primes table. */ \ |
| int hth_prime_idx; \ |
| } |
| |
| #define HT_INITIALIZER() \ |
| { NULL, 0, 0, 0, -1 } |
| |
| #ifdef HT_NO_CACHE_HASH_VALUES |
| #define HT_ENTRY(type) \ |
| struct { \ |
| struct type *hte_next; \ |
| } |
| #else |
| #define HT_ENTRY(type) \ |
| struct { \ |
| struct type *hte_next; \ |
| unsigned hte_hash; \ |
| } |
| #endif |
| |
| #define HT_EMPTY(head) \ |
| ((head)->hth_n_entries == 0) |
| |
| /* How many elements in 'head'? */ |
| #define HT_SIZE(head) \ |
| ((head)->hth_n_entries) |
| |
| /* Return memory usage for a hashtable (not counting the entries themselves) */ |
| #define HT_MEM_USAGE(head) \ |
| (sizeof(*head) + (head)->hth_table_length * sizeof(void*)) |
| |
| #define HT_FIND(name, head, elm) name##_HT_FIND((head), (elm)) |
| #define HT_INSERT(name, head, elm) name##_HT_INSERT((head), (elm)) |
| #define HT_REPLACE(name, head, elm) name##_HT_REPLACE((head), (elm)) |
| #define HT_REMOVE(name, head, elm) name##_HT_REMOVE((head), (elm)) |
| #define HT_START(name, head) name##_HT_START(head) |
| #define HT_NEXT(name, head, elm) name##_HT_NEXT((head), (elm)) |
| #define HT_NEXT_RMV(name, head, elm) name##_HT_NEXT_RMV((head), (elm)) |
| #define HT_CLEAR(name, head) name##_HT_CLEAR(head) |
| #define HT_INIT(name, head) name##_HT_INIT(head) |
| /* Helper: */ |
| static inline unsigned |
| ht_improve_hash_(unsigned h) |
| { |
| /* Aim to protect against poor hash functions by adding logic here |
| * - logic taken from java 1.4 hashtable source */ |
| h += ~(h << 9); |
| h ^= ((h >> 14) | (h << 18)); /* >>> */ |
| h += (h << 4); |
| h ^= ((h >> 10) | (h << 22)); /* >>> */ |
| return h; |
| } |
| |
| #if 0 |
| /** Basic string hash function, from Java standard String.hashCode(). */ |
| static inline unsigned |
| ht_string_hash_(const char *s) |
| { |
| unsigned h = 0; |
| int m = 1; |
| while (*s) { |
| h += ((signed char)*s++)*m; |
| m = (m<<5)-1; /* m *= 31 */ |
| } |
| return h; |
| } |
| #endif |
| |
| /** Basic string hash function, from Python's str.__hash__() */ |
| static inline unsigned |
| ht_string_hash_(const char *s) |
| { |
| unsigned h; |
| const unsigned char *cp = (const unsigned char *)s; |
| h = *cp << 7; |
| while (*cp) { |
| h = (1000003*h) ^ *cp++; |
| } |
| /* This conversion truncates the length of the string, but that's ok. */ |
| h ^= (unsigned)(cp-(const unsigned char*)s); |
| return h; |
| } |
| |
| #ifndef HT_NO_CACHE_HASH_VALUES |
| #define HT_SET_HASH_(elm, field, hashfn) \ |
| do { (elm)->field.hte_hash = hashfn(elm); } while (0) |
| #define HT_SET_HASHVAL_(elm, field, val) \ |
| do { (elm)->field.hte_hash = (val); } while (0) |
| #define HT_ELT_HASH_(elm, field, hashfn) \ |
| ((elm)->field.hte_hash) |
| #else |
| #define HT_SET_HASH_(elm, field, hashfn) \ |
| ((void)0) |
| #define HT_ELT_HASH_(elm, field, hashfn) \ |
| (hashfn(elm)) |
| #define HT_SET_HASHVAL_(elm, field, val) \ |
| ((void)0) |
| #endif |
| |
| /* Helper: alias for the bucket containing 'elm'. */ |
| #define HT_BUCKET_(head, field, elm, hashfn) \ |
| ((head)->hth_table[HT_ELT_HASH_(elm,field,hashfn) % head->hth_table_length]) |
| |
| #define HT_FOREACH(x, name, head) \ |
| for ((x) = HT_START(name, head); \ |
| (x) != NULL; \ |
| (x) = HT_NEXT(name, head, x)) |
| |
| #define HT_PROTOTYPE(name, type, field, hashfn, eqfn) \ |
| int name##_HT_GROW(struct name *ht, unsigned min_capacity); \ |
| void name##_HT_CLEAR(struct name *ht); \ |
| int name##_HT_REP_IS_BAD_(const struct name *ht); \ |
| static inline void \ |
| name##_HT_INIT(struct name *head) { \ |
| head->hth_table_length = 0; \ |
| head->hth_table = NULL; \ |
| head->hth_n_entries = 0; \ |
| head->hth_load_limit = 0; \ |
| head->hth_prime_idx = -1; \ |
| } \ |
| /* Helper: returns a pointer to the right location in the table \ |
| * 'head' to find or insert the element 'elm'. */ \ |
| static inline struct type ** \ |
| name##_HT_FIND_P_(struct name *head, struct type *elm) \ |
| { \ |
| struct type **p; \ |
| if (!head->hth_table) \ |
| return NULL; \ |
| p = &HT_BUCKET_(head, field, elm, hashfn); \ |
| while (*p) { \ |
| if (eqfn(*p, elm)) \ |
| return p; \ |
| p = &(*p)->field.hte_next; \ |
| } \ |
| return p; \ |
| } \ |
| /* Return a pointer to the element in the table 'head' matching 'elm', \ |
| * or NULL if no such element exists */ \ |
| static inline struct type * \ |
| name##_HT_FIND(const struct name *head, struct type *elm) \ |
| { \ |
| struct type **p; \ |
| struct name *h = (struct name *) head; \ |
| HT_SET_HASH_(elm, field, hashfn); \ |
| p = name##_HT_FIND_P_(h, elm); \ |
| return p ? *p : NULL; \ |
| } \ |
| /* Insert the element 'elm' into the table 'head'. Do not call this \ |
| * function if the table might already contain a matching element. */ \ |
| static inline void \ |
| name##_HT_INSERT(struct name *head, struct type *elm) \ |
| { \ |
| struct type **p; \ |
| if (!head->hth_table || head->hth_n_entries >= head->hth_load_limit) \ |
| name##_HT_GROW(head, head->hth_n_entries+1); \ |
| ++head->hth_n_entries; \ |
| HT_SET_HASH_(elm, field, hashfn); \ |
| p = &HT_BUCKET_(head, field, elm, hashfn); \ |
| elm->field.hte_next = *p; \ |
| *p = elm; \ |
| } \ |
| /* Insert the element 'elm' into the table 'head'. If there already \ |
| * a matching element in the table, replace that element and return \ |
| * it. */ \ |
| static inline struct type * \ |
| name##_HT_REPLACE(struct name *head, struct type *elm) \ |
| { \ |
| struct type **p, *r; \ |
| if (!head->hth_table || head->hth_n_entries >= head->hth_load_limit) \ |
| name##_HT_GROW(head, head->hth_n_entries+1); \ |
| HT_SET_HASH_(elm, field, hashfn); \ |
| p = name##_HT_FIND_P_(head, elm); \ |
| r = *p; \ |
| *p = elm; \ |
| if (r && (r!=elm)) { \ |
| elm->field.hte_next = r->field.hte_next; \ |
| r->field.hte_next = NULL; \ |
| return r; \ |
| } else { \ |
| ++head->hth_n_entries; \ |
| return NULL; \ |
| } \ |
| } \ |
| /* Remove any element matching 'elm' from the table 'head'. If such \ |
| * an element is found, return it; otherwise return NULL. */ \ |
| static inline struct type * \ |
| name##_HT_REMOVE(struct name *head, struct type *elm) \ |
| { \ |
| struct type **p, *r; \ |
| HT_SET_HASH_(elm, field, hashfn); \ |
| p = name##_HT_FIND_P_(head,elm); \ |
| if (!p || !*p) \ |
| return NULL; \ |
| r = *p; \ |
| *p = r->field.hte_next; \ |
| r->field.hte_next = NULL; \ |
| --head->hth_n_entries; \ |
| return r; \ |
| } \ |
| /* Invoke the function 'fn' on every element of the table 'head', \ |
| * using 'data' as its second argument. If the function returns \ |
| * nonzero, remove the most recently examined element before invoking \ |
| * the function again. */ \ |
| static inline void \ |
| name##_HT_FOREACH_FN(struct name *head, \ |
| int (*fn)(struct type *, void *), \ |
| void *data) \ |
| { \ |
| unsigned idx; \ |
| struct type **p, **nextp, *next; \ |
| if (!head->hth_table) \ |
| return; \ |
| for (idx=0; idx < head->hth_table_length; ++idx) { \ |
| p = &head->hth_table[idx]; \ |
| while (*p) { \ |
| nextp = &(*p)->field.hte_next; \ |
| next = *nextp; \ |
| if (fn(*p, data)) { \ |
| --head->hth_n_entries; \ |
| *p = next; \ |
| } else { \ |
| p = nextp; \ |
| } \ |
| } \ |
| } \ |
| } \ |
| /* Return a pointer to the first element in the table 'head', under \ |
| * an arbitrary order. This order is stable under remove operations, \ |
| * but not under others. If the table is empty, return NULL. */ \ |
| static inline struct type ** \ |
| name##_HT_START(struct name *head) \ |
| { \ |
| unsigned b = 0; \ |
| while (b < head->hth_table_length) { \ |
| if (head->hth_table[b]) \ |
| return &head->hth_table[b]; \ |
| ++b; \ |
| } \ |
| return NULL; \ |
| } \ |
| /* Return the next element in 'head' after 'elm', under the arbitrary \ |
| * order used by HT_START. If there are no more elements, return \ |
| * NULL. If 'elm' is to be removed from the table, you must call \ |
| * this function for the next value before you remove it. \ |
| */ \ |
| static inline struct type ** \ |
| name##_HT_NEXT(struct name *head, struct type **elm) \ |
| { \ |
| if ((*elm)->field.hte_next) { \ |
| return &(*elm)->field.hte_next; \ |
| } else { \ |
| unsigned b = (HT_ELT_HASH_(*elm, field, hashfn) % head->hth_table_length)+1; \ |
| while (b < head->hth_table_length) { \ |
| if (head->hth_table[b]) \ |
| return &head->hth_table[b]; \ |
| ++b; \ |
| } \ |
| return NULL; \ |
| } \ |
| } \ |
| static inline struct type ** \ |
| name##_HT_NEXT_RMV(struct name *head, struct type **elm) \ |
| { \ |
| unsigned h = HT_ELT_HASH_(*elm, field, hashfn); \ |
| *elm = (*elm)->field.hte_next; \ |
| --head->hth_n_entries; \ |
| if (*elm) { \ |
| return elm; \ |
| } else { \ |
| unsigned b = (h % head->hth_table_length)+1; \ |
| while (b < head->hth_table_length) { \ |
| if (head->hth_table[b]) \ |
| return &head->hth_table[b]; \ |
| ++b; \ |
| } \ |
| return NULL; \ |
| } \ |
| } |
| |
| #define HT_GENERATE(name, type, field, hashfn, eqfn, load, mallocfn, \ |
| reallocfn, freefn) \ |
| static unsigned name##_PRIMES[] = { \ |
| 53, 97, 193, 389, \ |
| 769, 1543, 3079, 6151, \ |
| 12289, 24593, 49157, 98317, \ |
| 196613, 393241, 786433, 1572869, \ |
| 3145739, 6291469, 12582917, 25165843, \ |
| 50331653, 100663319, 201326611, 402653189, \ |
| 805306457, 1610612741 \ |
| }; \ |
| static unsigned name##_N_PRIMES = \ |
| (unsigned)(sizeof(name##_PRIMES)/sizeof(name##_PRIMES[0])); \ |
| /* Expand the internal table of 'head' until it is large enough to \ |
| * hold 'size' elements. Return 0 on success, -1 on allocation \ |
| * failure. */ \ |
| int \ |
| name##_HT_GROW(struct name *head, unsigned size) \ |
| { \ |
| unsigned new_len, new_load_limit; \ |
| int prime_idx; \ |
| struct type **new_table; \ |
| if (head->hth_prime_idx == (int)name##_N_PRIMES - 1) \ |
| return 0; \ |
| if (head->hth_load_limit > size) \ |
| return 0; \ |
| prime_idx = head->hth_prime_idx; \ |
| do { \ |
| new_len = name##_PRIMES[++prime_idx]; \ |
| new_load_limit = (unsigned)(load*new_len); \ |
| } while (new_load_limit <= size && \ |
| prime_idx < (int)name##_N_PRIMES); \ |
| if ((new_table = mallocfn(new_len*sizeof(struct type*)))) { \ |
| unsigned b; \ |
| memset(new_table, 0, new_len*sizeof(struct type*)); \ |
| for (b = 0; b < head->hth_table_length; ++b) { \ |
| struct type *elm, *next; \ |
| unsigned b2; \ |
| elm = head->hth_table[b]; \ |
| while (elm) { \ |
| next = elm->field.hte_next; \ |
| b2 = HT_ELT_HASH_(elm, field, hashfn) % new_len; \ |
| elm->field.hte_next = new_table[b2]; \ |
| new_table[b2] = elm; \ |
| elm = next; \ |
| } \ |
| } \ |
| if (head->hth_table) \ |
| freefn(head->hth_table); \ |
| head->hth_table = new_table; \ |
| } else { \ |
| unsigned b, b2; \ |
| new_table = reallocfn(head->hth_table, new_len*sizeof(struct type*)); \ |
| if (!new_table) return -1; \ |
| memset(new_table + head->hth_table_length, 0, \ |
| (new_len - head->hth_table_length)*sizeof(struct type*)); \ |
| for (b=0; b < head->hth_table_length; ++b) { \ |
| struct type *e, **pE; \ |
| for (pE = &new_table[b], e = *pE; e != NULL; e = *pE) { \ |
| b2 = HT_ELT_HASH_(e, field, hashfn) % new_len; \ |
| if (b2 == b) { \ |
| pE = &e->field.hte_next; \ |
| } else { \ |
| *pE = e->field.hte_next; \ |
| e->field.hte_next = new_table[b2]; \ |
| new_table[b2] = e; \ |
| } \ |
| } \ |
| } \ |
| head->hth_table = new_table; \ |
| } \ |
| head->hth_table_length = new_len; \ |
| head->hth_prime_idx = prime_idx; \ |
| head->hth_load_limit = new_load_limit; \ |
| return 0; \ |
| } \ |
| /* Free all storage held by 'head'. Does not free 'head' itself, or \ |
| * individual elements. */ \ |
| void \ |
| name##_HT_CLEAR(struct name *head) \ |
| { \ |
| if (head->hth_table) \ |
| freefn(head->hth_table); \ |
| name##_HT_INIT(head); \ |
| } \ |
| /* Debugging helper: return false iff the representation of 'head' is \ |
| * internally consistent. */ \ |
| int \ |
| name##_HT_REP_IS_BAD_(const struct name *head) \ |
| { \ |
| unsigned n, i; \ |
| struct type *elm; \ |
| if (!head->hth_table_length) { \ |
| if (!head->hth_table && !head->hth_n_entries && \ |
| !head->hth_load_limit && head->hth_prime_idx == -1) \ |
| return 0; \ |
| else \ |
| return 1; \ |
| } \ |
| if (!head->hth_table || head->hth_prime_idx < 0 || \ |
| !head->hth_load_limit) \ |
| return 2; \ |
| if (head->hth_n_entries > head->hth_load_limit) \ |
| return 3; \ |
| if (head->hth_table_length != name##_PRIMES[head->hth_prime_idx]) \ |
| return 4; \ |
| if (head->hth_load_limit != (unsigned)(load*head->hth_table_length)) \ |
| return 5; \ |
| for (n = i = 0; i < head->hth_table_length; ++i) { \ |
| for (elm = head->hth_table[i]; elm; elm = elm->field.hte_next) { \ |
| if (HT_ELT_HASH_(elm, field, hashfn) != hashfn(elm)) \ |
| return 1000 + i; \ |
| if ((HT_ELT_HASH_(elm, field, hashfn) % head->hth_table_length) != i) \ |
| return 10000 + i; \ |
| ++n; \ |
| } \ |
| } \ |
| if (n != head->hth_n_entries) \ |
| return 6; \ |
| return 0; \ |
| } |
| |
| /** Implements an over-optimized "find and insert if absent" block; |
| * not meant for direct usage by typical code, or usage outside the critical |
| * path.*/ |
| #define HT_FIND_OR_INSERT_(name, field, hashfn, head, eltype, elm, var, y, n) \ |
| { \ |
| struct name *var##_head_ = head; \ |
| struct eltype **var; \ |
| if (!var##_head_->hth_table || \ |
| var##_head_->hth_n_entries >= var##_head_->hth_load_limit) \ |
| name##_HT_GROW(var##_head_, var##_head_->hth_n_entries+1); \ |
| HT_SET_HASH_((elm), field, hashfn); \ |
| var = name##_HT_FIND_P_(var##_head_, (elm)); \ |
| if (*var) { \ |
| y; \ |
| } else { \ |
| n; \ |
| } \ |
| } |
| #define HT_FOI_INSERT_(field, head, elm, newent, var) \ |
| { \ |
| HT_SET_HASHVAL_(newent, field, (elm)->field.hte_hash); \ |
| newent->field.hte_next = NULL; \ |
| *var = newent; \ |
| ++((head)->hth_n_entries); \ |
| } |
| |
| /* |
| * Copyright 2005, Nick Mathewson. Implementation logic is adapted from code |
| * by Christopher Clark, retrofit to allow drop-in memory management, and to |
| * use the same interface as Niels Provos's tree.h. This is probably still |
| * a derived work, so the original license below still applies. |
| * |
| * Copyright (c) 2002, Christopher Clark |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * * Neither the name of the original author; nor the names of any contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER |
| * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #endif |
| |
