#ifndef HASH_H #define HASH_H /* Hash table implementation from the GIT project. */ /* Copyright 2008 (C) Linus Torvalds, GPL version 2 */ /* * These are some simple generic hash table helper functions. * Not necessarily suitable for all users, but good for things * where you want to just keep track of a list of things, and * have a good hash to use on them. * * It keeps the hash table at roughly 50-75% free, so the memory * cost of the hash table itself is roughly * * 3 * 2*sizeof(void *) * nr_of_objects * * bytes. * * FIXME: on 64-bit architectures, we waste memory. It would be * good to have just 32-bit pointers, requiring a special allocator * for hashed entries or something. */ #include #define alloc_nr(x) (((x) + 16) * 3 / 2) #define INSERT_HASH_PROTOS(ops, table) \ do { \ void **pos = insert_hash((ops).key, &(ops), &(table)); \ /* We already had an entry there? */ \ if (pos) { \ (ops).next = *pos; \ *pos = &(ops); \ } \ } while (0) struct hash_table_entry { unsigned int hash; void *ptr; }; struct hash_table { unsigned int size, nr; struct hash_table_entry *array; }; extern void *lookup_hash(unsigned int hash, const struct hash_table *table); extern void **insert_hash(unsigned int hash, void *ptr, struct hash_table *table); extern void *remove_hash(unsigned int hash, void *ptr, void *ptr_next, struct hash_table *table); extern int for_each_hash(const struct hash_table *table, int (*fn)(void *)); extern int for_each_hash_int(const struct hash_table *table, int (*fn)(void *, int), int arg); extern void free_hash(struct hash_table *table); static inline void init_hash(struct hash_table *table) { table->size = 0; table->nr = 0; table->array = NULL; } static inline unsigned char icase_hash(unsigned char c) { return c & ~((c & 0x40) >> 1); } static inline unsigned int hash_name(const char *name, int namelen) { unsigned int hash = 0x123; do { unsigned char c = *name++; c = icase_hash(c); hash = hash * 101 + c; } while (--namelen); return hash; } #endif /* HASH_H */ 74613fb18dfd0a5aa99270ee2e72d5c808d7'>commitdiff

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