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/* $Id$ */
/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file newgrf_storage.h Functionality related to the temporary and persistent storage arrays for NewGRFs. */
#ifndef NEWGRF_STORAGE_H
#define NEWGRF_STORAGE_H
#include "core/alloc_func.hpp"
/**
* Base class for all NewGRF storage arrays. Nothing fancy, only here
* so we have a generalised class to use.
*/
struct BaseStorageArray
{
virtual ~BaseStorageArray();
/**
* Clear the changes made since the last ClearChanges.
* This can be done in two ways:
* - saving the changes permanently
* - reverting to the previous version
* @param keep_changes do we save or revert the changes since the last ClearChanges?
*/
virtual void ClearChanges(bool keep_changes) = 0;
/**
* Stores some value at a given position.
* @param pos the position to write at
* @param value the value to write
*/
virtual void Store(uint pos, int32 value) = 0;
};
/**
* Class for persistent storage of data.
* On ClearChanges that data is either reverted or saved.
* @param TYPE the type of variable to store.
* @param SIZE the size of the array.
*/
template <typename TYPE, uint SIZE>
struct PersistentStorageArray : BaseStorageArray {
TYPE storage[SIZE]; ///< Memory to for the storage array
TYPE *prev_storage; ///< Memory to store "old" states so we can revert them on the performance of test cases for commands etc.
/** Simply construct the array */
PersistentStorageArray() : prev_storage(NULL)
{
memset(this->storage, 0, sizeof(this->storage));
}
/** And free all data related to it */
~PersistentStorageArray()
{
free(this->prev_storage);
}
/** Resets all values to zero. */
void ResetToZero()
{
memset(this->storage, 0, sizeof(this->storage));
}
/**
* Stores some value at a given position.
* If there is no backup of the data that backup is made and then
* we write the data.
* @param pos the position to write at
* @param value the value to write
*/
void Store(uint pos, int32 value)
{
/* Out of the scope of the array */
if (pos >= SIZE) return;
/* The value hasn't changed, so we pretend nothing happened.
* Saves a few cycles and such and it's pretty easy to check. */
if (this->storage[pos] == value) return;
/* We do not have made a backup; lets do so */
if (this->prev_storage != NULL) {
this->prev_storage = MallocT<TYPE>(SIZE);
memcpy(this->prev_storage, this->storage, sizeof(this->storage));
/* We only need to register ourselves when we made the backup
* as that is the only time something will have changed */
AddChangedStorage(this);
}
this->storage[pos] = value;
}
/**
* Gets the value from a given position.
* @param pos the position to get the data from
* @return the data from that position
*/
TYPE Get(uint pos) const
{
/* Out of the scope of the array */
if (pos >= SIZE) return 0;
return this->storage[pos];
}
/**
* Clear the changes, or assign them permanently to the storage.
* @param keep_changes Whether to assign or ditch the changes.
*/
void ClearChanges(bool keep_changes)
{
assert(this->prev_storage != NULL);
if (!keep_changes) {
memcpy(this->storage, this->prev_storage, sizeof(this->storage));
}
free(this->prev_storage);
}
};
/**
* Class for temporary storage of data.
* On ClearChanges that data is always zero-ed.
* @param TYPE the type of variable to store.
* @param SIZE the size of the array.
*/
template <typename TYPE, uint SIZE>
struct TemporaryStorageArray : BaseStorageArray {
TYPE storage[SIZE]; ///< Memory to for the storage array
/** Simply construct the array */
TemporaryStorageArray()
{
memset(this->storage, 0, sizeof(this->storage));
}
/**
* Stores some value at a given position.
* @param pos the position to write at
* @param value the value to write
*/
void Store(uint pos, int32 value)
{
/* Out of the scope of the array */
if (pos >= SIZE) return;
this->storage[pos] = value;
AddChangedStorage(this);
}
/**
* Gets the value from a given position.
* @param pos the position to get the data from
* @return the data from that position
*/
TYPE Get(uint pos) const
{
/* Out of the scope of the array */
if (pos >= SIZE) return 0;
return this->storage[pos];
}
void ClearChanges(bool keep_changes)
{
memset(this->storage, 0, sizeof(this->storage));
}
};
void AddChangedStorage(BaseStorageArray *storage);
void ClearStorageChanges(bool keep_changes);
#endif /* NEWGRF_STORAGE_H */
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