tornavis/source/blender/blenlib/BLI_array_store.h

103 lines
3.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once
/** \file
* \ingroup bli
* \brief Efficient in-memory storage of multiple similar arrays.
*/
#ifdef __cplusplus
extern "C" {
#endif
typedef struct BArrayState BArrayState;
typedef struct BArrayStore BArrayStore;
/**
* Create a new array store, which can store any number of arrays
* as long as their stride matches.
*
* \param stride: `sizeof()` each element,
*
* \note while a stride of `1` will always work,
* its less efficient since duplicate chunks of memory will be searched
* at positions unaligned with the array data.
*
* \param chunk_count: Number of elements to split each chunk into.
* - A small value increases the ability to de-duplicate chunks,
* but adds overhead by increasing the number of chunks to look up when searching for duplicates,
* as well as some overhead constructing the original array again, with more calls to `memcpy`.
* - Larger values reduce the *book keeping* overhead,
* but increase the chance a small,
* isolated change will cause a larger amount of data to be duplicated.
*
* \return A new array store, to be freed with #BLI_array_store_destroy.
*/
BArrayStore *BLI_array_store_create(unsigned int stride, unsigned int chunk_count);
/**
* Free the #BArrayStore, including all states and chunks.
*/
void BLI_array_store_destroy(BArrayStore *bs);
/**
* Clear all contents, allowing reuse of \a bs.
*/
void BLI_array_store_clear(BArrayStore *bs);
/**
* Find the memory used by all states (expanded & real).
*
* \return the total amount of memory that would be used by getting the arrays for all states.
*/
size_t BLI_array_store_calc_size_expanded_get(const BArrayStore *bs);
/**
* \return the amount of memory used by all #BChunk.data
* (duplicate chunks are only counted once).
*/
size_t BLI_array_store_calc_size_compacted_get(const BArrayStore *bs);
/**
* \param data: Data used to create
* \param state_reference: The state to use as a reference when adding the new state,
* typically this is the previous state,
* however it can be any previously created state from this \a bs.
*
* \return The new state,
* which is used by the caller as a handle to get back the contents of \a data.
* This may be removed using #BLI_array_store_state_remove,
* otherwise it will be removed with #BLI_array_store_destroy.
*/
BArrayState *BLI_array_store_state_add(BArrayStore *bs,
const void *data,
size_t data_len,
const BArrayState *state_reference);
/**
* Remove a state and free any unused #BChunk data.
*
* The states can be freed in any order.
*/
void BLI_array_store_state_remove(BArrayStore *bs, BArrayState *state);
/**
* \return the expanded size of the array,
* use this to know how much memory to allocate #BLI_array_store_state_data_get's argument.
*/
size_t BLI_array_store_state_size_get(BArrayState *state);
/**
* Fill in existing allocated memory with the contents of \a state.
*/
void BLI_array_store_state_data_get(BArrayState *state, void *data);
/**
* Allocate an array for \a state and return it.
*/
void *BLI_array_store_state_data_get_alloc(BArrayState *state, size_t *r_data_len);
/**
* \note Only for tests.
*/
bool BLI_array_store_is_valid(BArrayStore *bs);
#ifdef __cplusplus
}
#endif