src/common/index-allocator.hpp

   1 /*
   2  * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef _COMMON_INDEX_ALLOCATOR_H
   9 #define _COMMON_INDEX_ALLOCATOR_H
  10
  11 #include <lttng/lttng-export.h>
  12
  13 #include <inttypes.h>
  14
  15 struct lttng_index_allocator;
  16
  17 enum lttng_index_allocator_status {
  18         LTTNG_INDEX_ALLOCATOR_STATUS_OK,
  19         LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY,
  20         LTTNG_INDEX_ALLOCATOR_STATUS_ERROR,
  21 };
  22
  23 /*
  24  * Create an index allocator of `index_count` slots.
  25  */
  26 extern "C" LTTNG_EXPORT struct lttng_index_allocator *
  27 lttng_index_allocator_create(uint64_t index_count);
  28
  29 /*
  30  * Get the number of indexes currently in use.
  31  */
  32 extern "C" LTTNG_EXPORT uint64_t
  33 lttng_index_allocator_get_index_count(struct lttng_index_allocator *allocator);
  34
  35 /*
  36  * Allocate (i.e. reserve) a slot.
  37  */
  38 extern "C" LTTNG_EXPORT enum lttng_index_allocator_status
  39 lttng_index_allocator_alloc(struct lttng_index_allocator *allocator, uint64_t *index);
  40
  41 /*
  42  * Release a slot by index. The slot will be re-used by the index allocator
  43  * in future 'alloc' calls.
  44  */
  45 extern "C" LTTNG_EXPORT enum lttng_index_allocator_status
  46 lttng_index_allocator_release(struct lttng_index_allocator *allocator, uint64_t index);
  47
  48 /*
  49  * Destroy an index allocator.
  50  */
  51 extern "C" LTTNG_EXPORT void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator);
  52
  53 #endif /* _COMMON_INDEX_ALLOCATOR_H */