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/*
* This file is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2,
* as published by the Free Software Foundation.
*
* In addition to the permissions in the GNU General Public License,
* the authors give you unlimited permission to link the compiled
* version of this file into combinations with other programs,
* and to distribute those combinations without any restriction
* coming from the use of this file. (The General Public License
* restrictions do apply in other respects; for example, they cover
* modification of the file, and distribution when not linked into
* a combined executable.)
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "common.h"
#include "revobject.h"
const float max_load_factor = 0.65;
unsigned int git_revpool_table__hash(const git_oid *id)
{
const unsigned int m = 0x5bd1e995;
const int r = 24;
unsigned int h = 0xA8A3D5;
int i;
for (i = 0; i < GIT_OID_RAWSZ / 4; ++i)
{
unsigned int k = ((unsigned int *)id->id)[i];
k *= m;
k ^= k >> r;
k *= m;
h *= m;
h ^= k;
}
h ^= h >> 13;
h *= m;
h ^= h >> 15;
return h;
}
git_revpool_table *git_revpool_table_create(unsigned int min_size)
{
git_revpool_table *table;
int i;
table = git__malloc(sizeof(table));
if (table == NULL)
return NULL;
// round up size to closest power of 2
min_size--;
min_size |= min_size >> 1;
min_size |= min_size >> 2;
min_size |= min_size >> 4;
min_size |= min_size >> 8;
min_size |= min_size >> 16;
table->size_mask = min_size;
table->count = 0;
table->max_count = (min_size + 1) * max_load_factor;
table->nodes = git__malloc((min_size + 1) * sizeof(git_revpool_node *));
if (table->nodes == NULL)
{
free(table);
return NULL;
}
for (i = 0; i <= min_size; ++i)
table->nodes[i] = NULL;
return table;
}
int git_revpool_table_insert(git_revpool_table *table, git_revpool_object *object)
{
git_revpool_node *node;
unsigned int index, hash;
if (table == NULL)
return -1;
if (table->count + 1 > table->max_count)
git_revpool_table_resize(table);
node = git__malloc(sizeof(git_revpool_node));
if (node == NULL)
return -1;
hash = git_revpool_table__hash(&object->id);
index = (hash & table->size_mask);
node->object = object;
node->hash = hash;
node->next = table->nodes[index];
table->nodes[index] = node;
table->count++;
return 0;
}
git_revpool_object *git_revpool_table_lookup(git_revpool_table *table, const git_oid *id)
{
git_revpool_node *node;
unsigned int index, hash;
if (table == NULL)
return NULL;
hash = git_revpool_table__hash(id);
index = (hash & table->size_mask);
node = table->nodes[index];
while (node != NULL)
{
if (node->hash == hash && git_oid_cmp(id, &node->object->id) == 0)
return node->object;
node = node->next;
}
return NULL;
}
void git_revpool_table_resize(git_revpool_table *table)
{
git_revpool_node **new_nodes;
unsigned int new_size, i;
new_size = (table->size_mask + 1) * 2;
new_nodes = git__malloc(new_size * sizeof(git_revpool_node *));
if (new_nodes == NULL)
return;
memset(new_nodes, 0x0, new_size * sizeof(git_revpool_node *));
for (i = 0; i <= table->size_mask; ++i)
{
git_revpool_node *n;
unsigned int index;
while ((n = table->nodes[i]) != NULL)
{
table->nodes[i] = n->next;
index = n->hash & (new_size - 1);
n->next = new_nodes[index];
new_nodes[index] = n;
}
}
free(table->nodes);
table->nodes = new_nodes;
table->size_mask = (new_size - 1);
table->max_count = new_size * max_load_factor;
}
void git_revpool_table_free(git_revpool_table *table)
{
}
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