/* Fixed size hash table with internal linking. Copyright (C) 2000, 2001, 2002, 2004, 2005 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper , 2000. This file is free software; you can redistribute it and/or modify it under the terms of either * the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version or * the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version or both in parallel, as here. elfutils is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received copies of the GNU General Public License and the GNU Lesser General Public License along with this program. If not, see . */ #include #include #include #include #include #ifdef __CONCAT #define CONCAT(t1,t2) __CONCAT (t1,t2) #else #define STROF(t2) t2 #define CONCAT_EXPANDED(t1,t2) t1 ## t2 #define CONCAT(t1,t2) CONCAT_EXPANDED(t1,t2) #endif /* Before including this file the following macros must be defined: TYPE data type of the hash table entries HASHFCT name of the hashing function to use HASHTYPE type used for the hashing value COMPARE comparison function taking two pointers to TYPE objects CLASS can be defined to `static' to avoid exporting the functions PREFIX prefix to be used for function and data type names STORE_POINTER if defined the table stores a pointer and not an element of type TYPE INSERT_HASH if defined alternate insert function which takes a hash value is defined NO_FINI_FCT if defined the fini function is not defined */ /* Defined separately. */ extern size_t next_prime (size_t seed); /* Set default values. */ #ifndef HASHTYPE # define HASHTYPE size_t #endif #ifndef CLASS # define CLASS #endif #ifndef PREFIX # define PREFIX #endif /* The data structure. */ struct CONCAT(PREFIX,fshash) { size_t nslots; struct CONCAT(PREFIX,fshashent) { HASHTYPE hval; #ifdef STORE_POINTER # define ENTRYP(el) (el).entry TYPE *entry; #else # define ENTRYP(el) &(el).entry TYPE entry; #endif } table[0]; }; /* Constructor for the hashing table. */ CLASS struct CONCAT(PREFIX,fshash) * CONCAT(PREFIX,fshash_init) (size_t nelems) { struct CONCAT(PREFIX,fshash) *result; /* We choose a size for the hashing table 150% over the number of entries. This will guarantee short medium search lengths. */ const size_t max_size_t = ~((size_t) 0); if (nelems >= (max_size_t / 3) * 2) { errno = EINVAL; return NULL; } /* Adjust the size to be used for the hashing table. */ nelems = next_prime (MAX ((nelems * 3) / 2, 10)); /* Allocate the data structure for the result. */ result = (struct CONCAT(PREFIX,fshash) *) xcalloc (sizeof (struct CONCAT(PREFIX,fshash)) + (nelems + 1) * sizeof (struct CONCAT(PREFIX,fshashent)), 1); if (result == NULL) return NULL; result->nslots = nelems; return result; } #ifndef NO_FINI_FCT CLASS void CONCAT(PREFIX,fshash_fini) (struct CONCAT(PREFIX,fshash) *htab) { free (htab); } #endif static struct CONCAT(PREFIX,fshashent) * CONCAT(PREFIX,fshash_lookup) (struct CONCAT(PREFIX,fshash) *htab, HASHTYPE hval, TYPE *data) { size_t idx = 1 + hval % htab->nslots; if (htab->table[idx].hval != 0) { HASHTYPE hash; /* See whether this is the same entry. */ if (htab->table[idx].hval == hval && COMPARE (data, ENTRYP (htab->table[idx])) == 0) return &htab->table[idx]; /* Second hash function as suggested in [Knuth]. */ hash = 1 + hval % (htab->nslots - 2); do { if (idx <= hash) idx = htab->nslots + idx - hash; else idx -= hash; if (htab->table[idx].hval == hval && COMPARE (data, ENTRYP(htab->table[idx])) == 0) return &htab->table[idx]; } while (htab->table[idx].hval != 0); } return &htab->table[idx]; } CLASS int __attribute__ ((unused)) CONCAT(PREFIX,fshash_insert) (struct CONCAT(PREFIX,fshash) *htab, const char *str, size_t len __attribute__ ((unused)), TYPE *data) { HASHTYPE hval = HASHFCT (str, len ?: strlen (str)); struct CONCAT(PREFIX,fshashent) *slot; slot = CONCAT(PREFIX,fshash_lookup) (htab, hval, data); if (slot->hval != 0) /* We don't want to overwrite the old value. */ return -1; slot->hval = hval; #ifdef STORE_POINTER slot->entry = data; #else slot->entry = *data; #endif return 0; } #ifdef INSERT_HASH CLASS int __attribute__ ((unused)) CONCAT(PREFIX,fshash_insert_hash) (struct CONCAT(PREFIX,fshash) *htab, HASHTYPE hval, TYPE *data) { struct CONCAT(PREFIX,fshashent) *slot; slot = CONCAT(PREFIX,fshash_lookup) (htab, hval, data); if (slot->hval != 0) /* We don't want to overwrite the old value. */ return -1; slot->hval = hval; #ifdef STORE_POINTER slot->entry = data; #else slot->entry = *data; #endif return 0; } #endif CLASS int __attribute__ ((unused)) CONCAT(PREFIX,fshash_overwrite) (struct CONCAT(PREFIX,fshash) *htab, const char *str, size_t len __attribute__ ((unused)), TYPE *data) { HASHTYPE hval = HASHFCT (str, len ?: strlen (str)); struct CONCAT(PREFIX,fshashent) *slot; slot = CONCAT(PREFIX,fshash_lookup) (htab, hval, data); slot->hval = hval; #ifdef STORE_POINTER slot->entry = data; #else slot->entry = *data; #endif return 0; } CLASS const TYPE * CONCAT(PREFIX,fshash_find) (const struct CONCAT(PREFIX,fshash) *htab, const char *str, size_t len __attribute__ ((unused)), TYPE *data) { HASHTYPE hval = HASHFCT (str, len ?: strlen (str)); struct CONCAT(PREFIX,fshashent) *slot; slot = CONCAT(PREFIX,fshash_lookup) ((struct CONCAT(PREFIX,fshash) *) htab, hval, data); if (slot->hval == 0) /* Not found. */ return NULL; return ENTRYP(*slot); } /* Unset the macros we expect. */ #undef TYPE #undef HASHFCT #undef HASHTYPE #undef COMPARE #undef CLASS #undef PREFIX #undef INSERT_HASH #undef STORE_POINTER #undef NO_FINI_FCT