147 lines
5.2 KiB
C++
147 lines
5.2 KiB
C++
/*
|
|
* Copyright (c) 2010-2013 BitTorrent, Inc.
|
|
*
|
|
* 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 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.
|
|
*/
|
|
|
|
#ifndef __UTP_HASH_H__
|
|
#define __UTP_HASH_H__
|
|
|
|
#include <string.h> // memset
|
|
#include <stdlib.h> // malloc
|
|
|
|
#include "utp_types.h"
|
|
#include "utp_templates.h"
|
|
|
|
// TODO: make utp_link_t a template parameter to HashTable
|
|
typedef uint32 utp_link_t;
|
|
|
|
#ifdef _MSC_VER
|
|
// Silence the warning about the C99-compliant zero-length array at the end of the structure
|
|
#pragma warning (disable: 4200)
|
|
#endif
|
|
|
|
typedef uint32 (*utp_hash_compute_t)(const void *keyp, size_t keysize);
|
|
typedef uint (*utp_hash_equal_t)(const void *key_a, const void *key_b, size_t keysize);
|
|
|
|
// In memory the HashTable is laid out as follows:
|
|
// ---------------------------- low
|
|
// | hash table data members |
|
|
// ---------------------------- _
|
|
// | indices | ^
|
|
// | . | | utp_link_t indices into the key-values.
|
|
// | . | .
|
|
// ---------------------------- - <----- bep
|
|
// | keys and values | each key-value pair has size total_size
|
|
// | . |
|
|
// | . |
|
|
// ---------------------------- high
|
|
//
|
|
// The code depends on the ability of the compiler to pad the length
|
|
// of the hash table data members structure to
|
|
// a length divisible by 32-bits with no remainder.
|
|
//
|
|
// Since the number of hash buckets (indices) should be odd, the code
|
|
// asserts this and adds one to the hash bucket count to ensure that the
|
|
// following key-value pairs array starts on a 32-bit boundary.
|
|
//
|
|
// The key-value pairs array should start on a 32-bit boundary, otherwise
|
|
// processors like the ARM will silently mangle 32-bit data in these structures
|
|
// (e.g., turning 0xABCD into 0XCDAB when moving a value from memory to register
|
|
// when the memory address is 16 bits offset from a 32-bit boundary),
|
|
// also, the value will be stored at an address two bytes lower than the address
|
|
// value would ordinarily indicate.
|
|
//
|
|
// The key-value pair is of type T. The first field in T must
|
|
// be the key, i.e., the first K bytes of T contains the key.
|
|
// total_size = sizeof(T) and thus sizeof(T) >= sizeof(K)
|
|
//
|
|
// N is the number of buckets.
|
|
//
|
|
struct utp_hash_t {
|
|
utp_link_t N;
|
|
byte K;
|
|
byte E;
|
|
size_t count;
|
|
utp_hash_compute_t hash_compute;
|
|
utp_hash_equal_t hash_equal;
|
|
utp_link_t allocated;
|
|
utp_link_t used;
|
|
utp_link_t free;
|
|
utp_link_t inits[0];
|
|
};
|
|
|
|
#ifdef _MSC_VER
|
|
#pragma warning (default: 4200)
|
|
#endif
|
|
|
|
struct utp_hash_iterator_t {
|
|
utp_link_t bucket;
|
|
utp_link_t elem;
|
|
|
|
utp_hash_iterator_t() : bucket(0xffffffff), elem(0xffffffff) {}
|
|
};
|
|
|
|
uint utp_hash_mem(const void *keyp, size_t keysize);
|
|
uint utp_hash_comp(const void *key_a, const void *key_b, size_t keysize);
|
|
|
|
utp_hash_t *utp_hash_create(int N, int key_size, int total_size, int initial, utp_hash_compute_t hashfun = utp_hash_mem, utp_hash_equal_t eqfun = NULL);
|
|
void *utp_hash_lookup(utp_hash_t *hash, const void *key);
|
|
void *utp_hash_add(utp_hash_t **hashp, const void *key);
|
|
void *utp_hash_del(utp_hash_t *hash, const void *key);
|
|
|
|
void *utp_hash_iterate(utp_hash_t *hash, utp_hash_iterator_t *iter);
|
|
void utp_hash_free_mem(utp_hash_t *hash);
|
|
|
|
/*
|
|
This HashTable requires that T have at least sizeof(K)+sizeof(utp_link_t) bytes.
|
|
Usually done like this:
|
|
|
|
struct K {
|
|
int whatever;
|
|
};
|
|
|
|
struct T {
|
|
K wtf;
|
|
utp_link_t link; // also wtf
|
|
};
|
|
*/
|
|
|
|
template<typename K, typename T> class utpHashTable {
|
|
utp_hash_t *hash;
|
|
public:
|
|
static uint compare(const void *k1, const void *k2, size_t ks) {
|
|
return *((K*)k1) == *((K*)k2);
|
|
}
|
|
static uint32 compute_hash(const void *k, size_t ks) {
|
|
return ((K*)k)->compute_hash();
|
|
}
|
|
void Init() { hash = NULL; }
|
|
bool Allocated() { return (hash != NULL); }
|
|
void Free() { utp_hash_free_mem(hash); hash = NULL; }
|
|
void Create(int N, int initial) { hash = utp_hash_create(N, sizeof(K), sizeof(T), initial, &compute_hash, &compare); }
|
|
T *Lookup(const K &key) { return (T*)utp_hash_lookup(hash, &key); }
|
|
T *Add(const K &key) { return (T*)utp_hash_add(&hash, &key); }
|
|
T *Delete(const K &key) { return (T*)utp_hash_del(hash, &key); }
|
|
T *Iterate(utp_hash_iterator_t &iterator) { return (T*)utp_hash_iterate(hash, &iterator); }
|
|
size_t GetCount() { return hash->count; }
|
|
};
|
|
|
|
#endif //__UTP_HASH_H__
|