radare2/libr/util/ht.c

262 lines
7.3 KiB
C

/*
* Copyright © 2009 Intel Corporation
* Copyright © 1988-2004 Keith Packard and Bart Massey.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Except as contained in this notice, the names of the authors
* or their institutions shall not be used in advertising or
* otherwise to promote the sale, use or other dealings in this
* Software without prior written authorization from the
* authors.
*
* Authors:
* Eric Anholt <eric@anholt.net>
* Keith Packard <keithp@keithp.com>
* Integration in r2 core api
* pancake <nopcode.org>
*/
#include <r_util.h>
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
/*
* From Knuth -- a good choice for hash/rehash values is p, p-2 where
* p and p-2 are both prime. These tables are sized to have an extra 10%
* free to avoid exponential performance degradation as the hash table fills
*/
#if HT64
#define utH ut64
#define ht_(name) r_hashtable64_##name
#define RHT RHashTable64
#define RHTE RHashTable64Entry
#else
#define utH ut32
#define ht_(name) r_hashtable_##name
#define RHT RHashTable
#define RHTE RHashTableEntry
#endif
//static const utH deleted_data;
// HACK :D .. but.. use magic instead?
#define deleted_data hash_sizes
static const struct {
// XXX: this can be ut32 ...
//ut32 max_entries, size, rehash;
#if HT64
ut64
#else
ut32
#endif
max_entries, size, rehash;
} hash_sizes[] = {
{ 2, 5, 3 },
{ 4, 7, 5 },
{ 8, 13, 11 },
{ 16, 19, 17 },
{ 32, 43, 41 },
{ 64, 73, 71 },
{ 128, 151, 149 },
{ 256, 283, 281 },
{ 512, 571, 569 },
{ 1024, 1153, 1151 },
{ 2048, 2269, 2267 },
{ 4096, 4519, 4517 },
{ 8192, 9013, 9011 },
{ 16384, 18043, 18041 },
{ 32768, 36109, 36107 },
{ 65536, 72091, 72089 },
{ 131072, 144409, 144407 },
{ 262144, 288361, 288359 },
{ 524288, 576883, 576881 },
{ 1048576, 1153459, 1153457 },
{ 2097152, 2307163, 2307161 },
{ 4194304, 4613893, 4613891 },
{ 8388608, 9227641, 9227639 },
{ 16777216, 18455029, 18455027 },
{ 33554432, 36911011, 36911009 },
{ 67108864, 73819861, 73819859 },
{ 134217728, 147639589, 147639587 },
{ 268435456, 295279081, 295279079 },
{ 536870912, 590559793, 590559791 },
{ 1073741824, 1181116273, 1181116271},
{ 2147483648ul, 2362232233ul, 2362232231ul}
};
#define entry_is_free(x) (!x || !x->data)
#define entry_is_deleted(x) x->data==&deleted_data
#define entry_is_present(x) (x->data && x->data != &deleted_data)
/**
* Finds a hash table entry with the given key and hash of that key.
*
* Returns NULL if no entry is found. Note that the data pointer may be
* modified by the user.
*/
static RHTE* ht_(search)(RHT *ht, utH hash) {
utH double_hash, hash_address;
if (ht == NULL)
return NULL;
hash_address = hash % ht->size;
do {
RHTE *entry = ht->table + hash_address;
if (entry_is_free (entry))
return NULL;
if (entry_is_present (entry) && entry->hash == hash)
return entry;
double_hash = hash % ht->rehash;
if (double_hash == 0)
double_hash = 1;
hash_address = (hash_address + double_hash) % ht->size;
} while (hash_address != hash % ht->size);
return NULL;
}
static void ht_(rehash)(RHT *ht, int new_size_index) {
RHT old_ht = *ht;
RHTE *e;
if (new_size_index >= ARRAY_SIZE (hash_sizes))
return;
// XXX: This code is redupped! fuck't
ht->table = calloc (hash_sizes[new_size_index].size, sizeof (*ht->table));
if (!ht->table)
return;
ht->size_index = new_size_index;
ht->size = hash_sizes[ht->size_index].size;
ht->rehash = hash_sizes[ht->size_index].rehash;
ht->max_entries = hash_sizes[ht->size_index].max_entries;
ht->entries = 0;
ht->deleted_entries = 0;
for (e = old_ht.table; e != old_ht.table + old_ht.size; e++) {
if (entry_is_present (e))
ht_(insert) (ht, e->hash, e->data);
}
free (old_ht.table);
}
R_API RHT* ht_(new)(void) {
RHT *ht = R_NEW (RHT);
if (!ht) return NULL;
// TODO: use slices here
ht->size = hash_sizes[0].size;
ht->table = calloc (ht->size, sizeof (*ht->table));
if (!ht->table) {
free (ht);
return NULL;
}
ht->size_index = 0;
ht->entries = 0;
ht->deleted_entries = 0;
ht->rehash = hash_sizes[ht->size_index].rehash;
ht->max_entries = hash_sizes[ht->size_index].max_entries;
return ht;
}
R_API void ht_(free)(RHT *ht) {
if (ht) {
free (ht->table);
free (ht);
}
}
R_API void *ht_(lookup)(RHT *ht, utH hash) {
if (ht) {
RHTE *entry = ht_(search) (ht, hash);
return entry? entry->data : NULL;
}
return NULL;
}
/**
* Inserts the data with the given hash into the table.
*
* Note that insertion may rearrange the table on a resize or rehash,
* so previously found hash_entries are no longer valid after this function.
*/
R_API bool ht_(insert) (RHT *ht, utH hash, void *data) {
utH hash_address;
if (ht->entries >= ht->max_entries)
ht_(rehash) (ht, ht->size_index + 1);
else if (ht->deleted_entries + ht->entries >= ht->max_entries)
ht_(rehash) (ht, ht->size_index);
hash_address = hash % ht->size;
do {
RHTE *entry = ht->table + hash_address;
utH double_hash;
if (!entry_is_present (entry)) {
if (entry_is_deleted (entry))
ht->deleted_entries--;
entry->hash = hash;
entry->data = data;
ht->entries++;
return R_TRUE;
}
double_hash = hash % ht->rehash;
if (double_hash == 0)
double_hash = 1;
hash_address = (hash_address + double_hash) % ht->size;
} while (hash_address != hash % ht->size);
/* We could hit here if a required resize failed. An unchecked-malloc
* application could ignore this result.
*/
return R_FALSE;
}
R_API void ht_(remove) (RHT *ht, utH hash) {
RHTE *entry = ht_(search) (ht, hash);
if (entry) {
entry->data = (void *) &deleted_data;
ht->entries--;
ht->deleted_entries++;
}
}
#if TEST
int main () {
const char *str;
int ret;
RHT *ht = ht_(new) ();
#define HASH 268453705
ret = ht_(insert) (ht, HASH, "patata");
if (!ret)
printf ("Cannot reinsert !!1\n");
str = ht_(lookup) (ht, HASH);
if (str) printf ("String is (%s)\n", str);
else printf ("Cannot find string\n");
ht_(remove) (ht, HASH);
str = ht_(lookup) (ht, HASH);
if (str) printf ("String is (%s)\n", str);
else printf("Cannot find string which is ok :)\n");
ht_(search) (ht, HASH);
ht_(free) (ht);
}
#endif