Merge pull request #59 from electronjoe/graceful-SIGTERM-handling
[netsniff-ng-old.git] / hash.h
blob8e261743ea29ddae48fb1136a626770ced155172
1 /*
2 * netsniff-ng - the packet sniffing beast
3 * Copyright 2009, 2010 Daniel Borkmann.
4 * Subject to the GPL, version 2.
5 */
7 #ifndef HASH_H
8 #define HASH_H
10 /* Hash table implementation from the GIT project. */
11 /* Copyright 2008 (C) Linus Torvalds, GPL version 2 */
13 * These are some simple generic hash table helper functions.
14 * Not necessarily suitable for all users, but good for things
15 * where you want to just keep track of a list of things, and
16 * have a good hash to use on them.
18 * It keeps the hash table at roughly 50-75% free, so the memory
19 * cost of the hash table itself is roughly
21 * 3 * 2*sizeof(void *) * nr_of_objects
23 * bytes.
25 * FIXME: on 64-bit architectures, we waste memory. It would be
26 * good to have just 32-bit pointers, requiring a special allocator
27 * for hashed entries or something.
30 #include <stdio.h>
32 #define alloc_nr(x) (((x) + 16) * 3 / 2)
33 #define INSERT_HASH_PROTOS(ops, table) \
34 do { \
35 void **pos = insert_hash((ops).key, &(ops), &(table)); \
36 /* We already had an entry there? */ \
37 if (pos) { \
38 (ops).next = *pos; \
39 *pos = &(ops); \
40 } \
41 } while (0)
43 struct hash_table_entry {
44 unsigned int hash;
45 void *ptr;
48 struct hash_table {
49 unsigned int size, nr;
50 struct hash_table_entry *array;
53 extern void *lookup_hash(unsigned int hash, const struct hash_table *table);
54 extern void **insert_hash(unsigned int hash, void *ptr,
55 struct hash_table *table);
56 extern void *remove_hash(unsigned int hash, void *ptr, void *ptr_next,
57 struct hash_table *table);
58 extern int for_each_hash(const struct hash_table *table, int (*fn)(void *));
59 extern int for_each_hash_int(const struct hash_table *table,
60 int (*fn)(void *, int), int arg);
61 extern void free_hash(struct hash_table *table);
63 static inline void init_hash(struct hash_table *table)
65 table->size = 0;
66 table->nr = 0;
67 table->array = NULL;
70 static inline unsigned char icase_hash(unsigned char c)
72 return c & ~((c & 0x40) >> 1);
75 static inline unsigned int hash_name(const char *name, int namelen)
77 unsigned int hash = 0x123;
78 do {
79 unsigned char c = *name++;
80 c = icase_hash(c);
81 hash = hash * 101 + c;
82 } while (--namelen);
83 return hash;
86 #endif