thodg/libgit2/src/revobject.c

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• Hash : f2924934
  Author :
  Date : 2010-06-01T19:41:55
  

  Style: Do not use (C99) // comments Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Andreas Ericsson <ae@op5.se>

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• src/revobject.c

• /*
   * 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"
  
  static const double max_load_factor = 0.65;
  
  static unsigned int git_revpool_table__hash(const git_oid *id)
  {
  	unsigned int r;
  	memcpy(&r, id->id, sizeof(r));
  	return r;
  }
  
  git_revpool_table *git_revpool_table_create(unsigned int min_size)
  {
  	git_revpool_table *table;
  	unsigned 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 = (unsigned int)((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 GIT_ERROR;
  
  	if (table->count + 1 > table->max_count)
  		git_revpool_table_resize(table);
  
  	node = git__malloc(sizeof(git_revpool_node));
  	if (node == NULL)
  		return GIT_ENOMEM;
  
  	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 = (unsigned int)(new_size * max_load_factor);
  }
  
  
  void git_revpool_table_free(git_revpool_table *table)
  {
  	unsigned int index;
  
  	for (index = 0; index <= table->size_mask; ++index) {
  		git_revpool_node *node, *next_node;
  
  		node = table->nodes[index];
  		while (node != NULL) {
  			next_node = node->next;
  			free(node);
  			node = next_node;
  		}
  	}
  
  	free(table->nodes);
  	free(table);
  }
  
  void git_revpool_tableit_init(git_revpool_table *table, git_revpool_tableit *it)
  {
  	memset(it, 0x0, sizeof(git_revpool_tableit));
  
  	it->nodes = table->nodes;
  	it->current_node = NULL;
  	it->current_pos = 0;
  	it->size = table->size_mask + 1;
  }
  
  git_revpool_object *git_revpool_tableit_next(git_revpool_tableit *it)
  {
  	git_revpool_node *next = NULL;
  
  	while (it->current_node == NULL) {
  		if (it->current_pos >= it->size)
  			return NULL;
  
  		it->current_node = it->nodes[it->current_pos++];
  	}
  
  	next = it->current_node;
  	it->current_node = it->current_node->next;
  
  	return next->object;
  }
  

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