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/*
* 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/pool_type.hpp"
#include "tile_type.h"
/**
* Mode switches to the behaviour of persistent storage array.
*/
enum PersistentStorageMode {
PSM_ENTER_GAMELOOP, ///< Enter the gameloop, changes will be permanent.
PSM_LEAVE_GAMELOOP, ///< Leave the gameloop, changes will be temporary.
PSM_ENTER_COMMAND, ///< Enter command scope, changes will be permanent.
PSM_LEAVE_COMMAND, ///< Leave command scope, revert to previous mode.
PSM_ENTER_TESTMODE, ///< Enter command test mode, changes will be tempoary.
PSM_LEAVE_TESTMODE, ///< Leave command test mode, revert to previous mode.
};
/**
* Base class for all persistent NewGRF storage arrays. Nothing fancy, only here
* so we have a generalised access to the virtual methods.
*/
struct BasePersistentStorageArray {
uint32 grfid; ///< GRFID associated to this persistent storage. A value of zero means "default".
byte feature; ///< NOSAVE: Used to identify in the owner of the array in debug output.
TileIndex tile; ///< NOSAVE: Used to identify in the owner of the array in debug output.
virtual ~BasePersistentStorageArray();
static void SwitchMode(PersistentStorageMode mode, bool ignore_prev_mode = false);
protected:
/**
* Discard temporary changes.
*/
virtual void ClearChanges() = 0;
/**
* Check whether currently changes to the storage shall be persistent or
* temporary till the next call to ClearChanges().
*/
static bool AreChangesPersistent() { return (gameloop || command) && !testmode; }
private:
static bool gameloop;
static bool command;
static bool testmode;
};
/**
* Class for persistent storage of data.
* On #ClearChanges that data is either reverted or saved.
* @tparam TYPE the type of variable to store.
* @tparam SIZE the size of the array.
*/
template <typename TYPE, uint SIZE>
struct PersistentStorageArray : BasePersistentStorageArray {
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(nullptr)
{
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 StoreValue(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 (AreChangesPersistent()) {
assert(this->prev_storage == nullptr);
} else if (this->prev_storage == nullptr) {
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 */
AddChangedPersistentStorage(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 GetValue(uint pos) const
{
/* Out of the scope of the array */
if (pos >= SIZE) return 0;
return this->storage[pos];
}
void ClearChanges()
{
if (this->prev_storage != nullptr) {
memcpy(this->storage, this->prev_storage, sizeof(this->storage));
free(this->prev_storage);
this->prev_storage = nullptr;
}
}
};
/**
* Class for temporary storage of data.
* On #ClearChanges that data is always zero-ed.
* @tparam TYPE the type of variable to store.
* @tparam SIZE the size of the array.
*/
template <typename TYPE, uint SIZE>
struct TemporaryStorageArray {
TYPE storage[SIZE]; ///< Memory to for the storage array
uint16 init[SIZE]; ///< Storage has been assigned, if this equals 'init_key'.
uint16 init_key; ///< Magic key to 'init'.
/** Simply construct the array */
TemporaryStorageArray()
{
memset(this->storage, 0, sizeof(this->storage)); // not exactly needed, but makes code analysers happy
memset(this->init, 0, sizeof(this->init));
this->init_key = 1;
}
/**
* Stores some value at a given position.
* @param pos the position to write at
* @param value the value to write
*/
void StoreValue(uint pos, int32 value)
{
/* Out of the scope of the array */
if (pos >= SIZE) return;
this->storage[pos] = value;
this->init[pos] = this->init_key;
}
/**
* Gets the value from a given position.
* @param pos the position to get the data from
* @return the data from that position
*/
TYPE GetValue(uint pos) const
{
/* Out of the scope of the array */
if (pos >= SIZE) return 0;
if (this->init[pos] != this->init_key) {
/* Unassigned since last call to ClearChanges */
return 0;
}
return this->storage[pos];
}
void ClearChanges()
{
/* Increment init_key to invalidate all storage */
this->init_key++;
if (this->init_key == 0) {
/* When init_key wraps around, we need to reset everything */
memset(this->init, 0, sizeof(this->init));
this->init_key = 1;
}
}
};
void AddChangedPersistentStorage(BasePersistentStorageArray *storage);
typedef PersistentStorageArray<int32, 16> OldPersistentStorage;
typedef uint32 PersistentStorageID;
struct PersistentStorage;
typedef Pool<PersistentStorage, PersistentStorageID, 1, 0xFF000> PersistentStoragePool;
extern PersistentStoragePool _persistent_storage_pool;
/**
* Class for pooled persistent storage of data.
*/
struct PersistentStorage : PersistentStorageArray<int32, 256>, PersistentStoragePool::PoolItem<&_persistent_storage_pool> {
/** We don't want GCC to zero our struct! It already is zeroed and has an index! */
PersistentStorage(const uint32 new_grfid, byte feature, TileIndex tile)
{
this->grfid = new_grfid;
this->feature = feature;
this->tile = tile;
}
};
static_assert(cpp_lengthof(OldPersistentStorage, storage) <= cpp_lengthof(PersistentStorage, storage));
#endif /* NEWGRF_STORAGE_H */
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