minetest/src/objdef.cpp

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/*
Minetest
Copyright (C) 2010-2015 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "objdef.h"
#include "util/numeric.h"
#include "log.h"
#include "gamedef.h"
ObjDefManager::ObjDefManager(IGameDef *gamedef, ObjDefType type)
{
m_objtype = type;
m_ndef = gamedef ? gamedef->getNodeDefManager() : NULL;
}
ObjDefManager::~ObjDefManager()
{
for (size_t i = 0; i != m_objects.size(); i++)
delete m_objects[i];
}
ObjDefHandle ObjDefManager::add(ObjDef *obj)
{
assert(obj);
if (obj->name.length() && getByName(obj->name))
return OBJDEF_INVALID_HANDLE;
u32 index = addRaw(obj);
if (index == OBJDEF_INVALID_INDEX)
return OBJDEF_INVALID_HANDLE;
obj->handle = createHandle(index, m_objtype, obj->uid);
return obj->handle;
}
ObjDef *ObjDefManager::get(ObjDefHandle handle) const
{
u32 index = validateHandle(handle);
return (index != OBJDEF_INVALID_INDEX) ? getRaw(index) : NULL;
}
ObjDef *ObjDefManager::set(ObjDefHandle handle, ObjDef *obj)
{
u32 index = validateHandle(handle);
if (index == OBJDEF_INVALID_INDEX)
return NULL;
ObjDef *oldobj = setRaw(index, obj);
obj->uid = oldobj->uid;
obj->index = oldobj->index;
obj->handle = oldobj->handle;
return oldobj;
}
u32 ObjDefManager::addRaw(ObjDef *obj)
{
size_t nobjects = m_objects.size();
if (nobjects >= OBJDEF_MAX_ITEMS)
return -1;
obj->index = nobjects;
// Ensure UID is nonzero so that a valid handle == OBJDEF_INVALID_HANDLE
// is not possible. The slight randomness bias isn't very significant.
obj->uid = myrand() & OBJDEF_UID_MASK;
if (obj->uid == 0)
obj->uid = 1;
m_objects.push_back(obj);
infostream << "ObjDefManager: added " << getObjectTitle()
<< ": name=\"" << obj->name
<< "\" index=" << obj->index
<< " uid=" << obj->uid
<< std::endl;
return nobjects;
}
ObjDef *ObjDefManager::getRaw(u32 index) const
{
return m_objects[index];
}
ObjDef *ObjDefManager::setRaw(u32 index, ObjDef *obj)
{
ObjDef *old_obj = m_objects[index];
m_objects[index] = obj;
return old_obj;
}
ObjDef *ObjDefManager::getByName(const std::string &name) const
{
for (size_t i = 0; i != m_objects.size(); i++) {
ObjDef *obj = m_objects[i];
if (obj && !strcasecmp(name.c_str(), obj->name.c_str()))
return obj;
}
return NULL;
}
void ObjDefManager::clear()
{
for (size_t i = 0; i != m_objects.size(); i++)
delete m_objects[i];
m_objects.clear();
}
u32 ObjDefManager::validateHandle(ObjDefHandle handle) const
{
ObjDefType type;
u32 index;
u32 uid;
bool is_valid =
(handle != OBJDEF_INVALID_HANDLE) &&
decodeHandle(handle, &index, &type, &uid) &&
(type == m_objtype) &&
(index < m_objects.size()) &&
(m_objects[index]->uid == uid);
return is_valid ? index : -1;
}
ObjDefHandle ObjDefManager::createHandle(u32 index, ObjDefType type, u32 uid)
{
ObjDefHandle handle = 0;
set_bits(&handle, 0, 18, index);
set_bits(&handle, 18, 6, type);
set_bits(&handle, 24, 7, uid);
u32 parity = calc_parity(handle);
set_bits(&handle, 31, 1, parity);
return handle ^ OBJDEF_HANDLE_SALT;
}
bool ObjDefManager::decodeHandle(ObjDefHandle handle, u32 *index,
ObjDefType *type, u32 *uid)
{
handle ^= OBJDEF_HANDLE_SALT;
u32 parity = get_bits(handle, 31, 1);
set_bits(&handle, 31, 1, 0);
if (parity != calc_parity(handle))
return false;
*index = get_bits(handle, 0, 18);
*type = (ObjDefType)get_bits(handle, 18, 6);
*uid = get_bits(handle, 24, 7);
return true;
}