/* $Id$ */ /** @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 { /** The needed destructor */ 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, uint32 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); } /** * 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, uint32 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); if (this->prev_storage == NULL) return; 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]; } 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, uint32 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)); } }; /** * Add the changed storage array to the list of changed arrays. * This is done so we only have to revert/save the changed * arrays, which saves quite a few clears, etc. after callbacks. * @param storage the array that has changed */ void AddChangedStorage(BaseStorageArray *storage); /** * Clear the changes made since the last ClearStorageChanges. * This is done for *all* storages that have been registered to with * AddChangedStorage since the previous ClearStorageChanges. * * 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? */ void ClearStorageChanges(bool keep_changes); #endif /* NEWGRF_STORAGE_H */