kc3-lang/libevent/ht-internal.h
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Hash : 78eb3059
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Date : 2024-11-02T21:41:32
Fix unlikely (for libevent) UB in HT_GROW() The reason it is not possible for libevent is that: a) it is unlikely to have 1610612741 elements b) growing is done incrementally (i.e. only internally by HT_INSERT) and in this case the UB is not possible Fixes: https://github.com/libevent/libevent/issues/1312
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ht-internal.h
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/* 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])) - 1; \ /* 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) \ 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