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much better hash for address map
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@gafferongames
gafferongames committed Jan 9, 2024
1 parent 268ca89 commit e70745e
Showing 1 changed file with 84 additions and 50 deletions.
134 changes: 84 additions & 50 deletions netcode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3774,10 +3774,83 @@ struct netcode_address_map_t
struct netcode_address_map_bucket_t buckets[NETCODE_ADDRESS_MAP_BUCKETS];
};

static void netcode_address_map_reset( struct netcode_address_map_t * map );

struct netcode_address_map_t * netcode_address_map_create( void * allocator_context,
void * (*allocate_function)(void*,size_t),
void (*free_function)(void*,void*) )
{
if ( allocate_function == NULL )
{
allocate_function = netcode_default_allocate_function;
}

if ( free_function == NULL )
{
free_function = netcode_default_free_function;
}

struct netcode_address_map_t * map = (struct netcode_address_map_t*)
allocate_function( allocator_context, sizeof( struct netcode_address_map_t ) );

netcode_assert( map );

netcode_address_map_reset( map );

map->allocator_context = allocator_context;
map->allocate_function = allocate_function;
map->free_function = free_function;

return map;
}

void netcode_address_map_destroy( struct netcode_address_map_t * map )
{
netcode_assert( map );
netcode_assert( map->free_function );
map->free_function( map->allocator_context, map );
}

typedef uint64_t netcode_fnv_t;

void netcode_fnv_init( netcode_fnv_t * fnv )
{
*fnv = 0xCBF29CE484222325;
}

void netcode_fnv_write( netcode_fnv_t * fnv, const uint8_t * data, size_t size )
{
for ( size_t i = 0; i < size; i++ )
{
(*fnv) ^= data[i];
(*fnv) *= 0x00000100000001B3;
}
}

uint64_t netcode_fnv_finalize( netcode_fnv_t * fnv )
{
return *fnv;
}

uint64_t netcode_hash_string( const char * string )
{
netcode_fnv_t fnv;
netcode_fnv_init( &fnv );
netcode_fnv_write( &fnv, (uint8_t *)( string ), strlen( string ) );
return netcode_fnv_finalize( &fnv );
}

uint64_t netcode_hash_data( const uint8_t * data, size_t size )
{
netcode_fnv_t fnv;
netcode_fnv_init( &fnv );
netcode_fnv_write( &fnv, (uint8_t *)( data ), size );
return netcode_fnv_finalize( &fnv );
}

static int netcode_address_hash( struct netcode_address_t * address )
{
// todo: this is a really bad hash. let's make it better
return address->port % NETCODE_ADDRESS_MAP_BUCKETS;
return netcode_hash_data( (const uint8_t*) address, sizeof(struct netcode_address_t) ) % NETCODE_ADDRESS_MAP_BUCKETS;
}

static void netcode_address_map_element_reset( struct netcode_address_map_element_t * element )
Expand All @@ -3793,7 +3866,7 @@ static void netcode_address_map_bucket_reset( struct netcode_address_map_bucket_
for ( i = 0; i < NETCODE_MAX_CLIENTS; i++ )
{
struct netcode_address_map_element_t * element = bucket->elements + i;
netcode_address_map_element_reset(element);
netcode_address_map_element_reset( element );
}
}

Expand Down Expand Up @@ -3883,43 +3956,6 @@ static int netcode_address_map_delete( struct netcode_address_map_t * map,
return 1;
}

// todo: while this method is defined, it is not used anywhere
struct netcode_address_map_t * netcode_address_map_create( void * allocator_context,
void * (*allocate_function)(void*,size_t),
void (*free_function)(void*,void*) )
{
if ( allocate_function == NULL )
{
allocate_function = netcode_default_allocate_function;
}

if ( free_function == NULL )
{
free_function = netcode_default_free_function;
}

struct netcode_address_map_t * map = (struct netcode_address_map_t*)
allocate_function( allocator_context, sizeof( struct netcode_address_map_t ) );

netcode_assert( map );

netcode_address_map_reset( map );

map->allocator_context = allocator_context;
map->allocate_function = allocate_function;
map->free_function = free_function;

return map;
}

// todo: this method is defined but not used anywhere
void netcode_address_map_destroy( struct netcode_address_map_t * map )
{
netcode_assert( map );
netcode_assert( map->free_function );
map->free_function( map->allocator_context, map );
}

// ----------------------------------------------------------------

#define NETCODE_SERVER_FLAG_IGNORE_CONNECTION_REQUEST_PACKETS 1
Expand Down Expand Up @@ -9086,11 +9122,11 @@ void test_address_map()
const char * str_address_3 = "fe80::202:b3ff:fe1e:8329";
const char * str_address_4 = "fe80::202:b3ff:fe1e:8330";

// todo: test should use the create methods w. allocator
struct netcode_address_map_t * map = (struct netcode_address_map_t *) malloc( sizeof( struct netcode_address_map_t ) );
struct netcode_address_map_t * map = netcode_address_map_create( NULL, NULL, NULL );

struct netcode_address_t address_set;
struct netcode_address_t address_get;
struct netcode_address_t address_del;
struct netcode_address_t address_delete;

netcode_address_map_reset( map );

Expand Down Expand Up @@ -9119,17 +9155,16 @@ void test_address_map()
check( netcode_address_map_get( map, &address_get ) == -1);

// Try to delete key, after that, the key should be disappear
netcode_parse_address( str_address_1, &address_del );
netcode_parse_address( str_address_1, &address_delete );
netcode_parse_address( str_address_1, &address_get );
check( netcode_address_map_delete( map, &address_del ) == 1 );
check( netcode_address_map_delete( map, &address_delete ) == 1 );
check( netcode_address_map_get( map, &address_get ) == -1 );

// Try to delete non-existent key
netcode_parse_address( str_address_2, &address_del );
check ( netcode_address_map_delete( map, &address_del ) == 0 );
netcode_parse_address( str_address_2, &address_delete );
check ( netcode_address_map_delete( map, &address_delete ) == 0 );

// todo: should use netcode_address_map_destroy
free( map );
netcode_address_map_destroy( map );
}

#define RUN_TEST( test_function ) \
Expand Down Expand Up @@ -9183,4 +9218,3 @@ void netcode_test()
}

#endif // #if NETCODE_ENABLE_TESTS

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