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Optimize binary_search function

master
Dirk Engling 11 years ago
parent
commit
842a3db5d9
1 changed files with 18 additions and 42 deletions
  1. +18
    -42
      ot_vector.c

+ 18
- 42
ot_vector.c View File

@@ -6,6 +6,7 @@
/* System */
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <stdint.h>

/* Opentracker */
@@ -26,51 +27,26 @@ static int vector_compare_peer(const void *peer1, const void *peer2 ) {
*/
void *binary_search( const void * const key, const void * base, const size_t member_count, const size_t member_size,
size_t compare_size, int *exactmatch ) {
size_t mc = member_count;
int8_t *lookat = ((int8_t*)base) + member_size * (mc >> 1);
*exactmatch = 1;

while( mc ) {
int32_t cmp = memcmp( lookat, key, compare_size );
if( cmp == 0 )
return (void *)lookat;

if (cmp < 0) {
base = (void*)(lookat + member_size);
--mc;
size_t interval = member_count * member_size;

while( interval ) {
uint8_t *lookat = ((uint8_t*)base) + interval / 2;
int cmp = memcmp( lookat, key, compare_size );
if(cmp == 0 ) {
base = lookat;
break;
}

mc >>= 1;
lookat = ((int8_t*)base) + member_size * (mc >> 1);
}

*exactmatch = 0;
return (void*)lookat;
}

ot_peer *binary_search_peer( const ot_peer * const peer, const ot_peer * base, const size_t member_count, int *exactmatch ) {
size_t mc = member_count;
const ot_peer *lookat = base + (mc >> 1);
*exactmatch = 1;

while( mc ) {
int32_t cmp = memcmp(lookat,peer,OT_PEER_COMPARE_SIZE );
if(cmp == 0) return (ot_peer*)lookat;

if (cmp < 0) {
base = lookat + 1;
--mc;
if(cmp < 0) {
base = lookat + member_size;
interval -= member_size;
}

mc >>= 1;
lookat = base + (mc >> 1);
interval /= 2;
}

*exactmatch = 0;
return (ot_peer*)lookat;
*exactmatch = interval;
return (void*)base;
}


static uint8_t vector_hash_peer( ot_peer *peer, int bucket_count ) {
unsigned int hash = 5381, i = OT_PEER_COMPARE_SIZE;
uint8_t *p = (uint8_t*)peer;
@@ -112,7 +88,7 @@ ot_peer *vector_find_or_insert_peer( ot_vector *vector, ot_peer *peer, int *exac
/* If space is zero but size is set, we're dealing with a list of vector->size buckets */
if( vector->space < vector->size )
vector = ((ot_vector*)vector->data) + vector_hash_peer(peer, vector->size );
match = binary_search_peer( peer, vector->data, vector->size, exactmatch );
match = (ot_peer*)binary_search( peer, vector->data, vector->size, sizeof(ot_peer), OT_PEER_COMPARE_SIZE, exactmatch );

if( *exactmatch ) return match;

@@ -148,7 +124,7 @@ int vector_remove_peer( ot_vector *vector, ot_peer *peer ) {
vector = ((ot_vector*)vector->data) + vector_hash_peer(peer, vector->size );

end = ((ot_peer*)vector->data) + vector->size;
match = binary_search_peer( peer, vector->data, vector->size, &exactmatch );
match = (ot_peer*)binary_search( peer, vector->data, vector->size, sizeof(ot_peer), OT_PEER_COMPARE_SIZE, &exactmatch );
if( !exactmatch ) return 0;

exactmatch = ( OT_PEERFLAG( match ) & PEER_FLAG_SEEDING ) ? 2 : 1;
@@ -287,4 +263,4 @@ void vector_fixup_peers( ot_vector * vector ) {
vector->data = realloc( vector->data, vector->space * sizeof( ot_peer ) );
}

const char *g_version_vector_c = "$Source: /home/cvsroot/opentracker/ot_vector.c,v $: $Revision: 1.16 $\n";
const char *g_version_vector_c = "$Source: /home/cvsroot/opentracker/ot_vector.c,v $: $Revision: 1.17 $\n";

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