src/common/index-allocator.h

   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 <inttypes.h>
  12
  13 struct lttng_index_allocator;
  14
  15 enum lttng_index_allocator_status {
  16         LTTNG_INDEX_ALLOCATOR_STATUS_OK,
  17         LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY,
  18         LTTNG_INDEX_ALLOCATOR_STATUS_ERROR,
  19 };
  20
  21 /*
  22  * Create an index allocator of `index_count` slots.
  23  */
  24 struct lttng_index_allocator *lttng_index_allocator_create(
  25                 uint64_t index_count);
  26
  27 /*
  28  * Get the number of indexes currently in use.
  29  */
  30 uint64_t lttng_index_allocator_get_index_count(
  31         struct lttng_index_allocator *allocator);
  32
  33 /*
  34  * Allocate (i.e. reserve) a slot.
  35  */
  36 enum lttng_index_allocator_status lttng_index_allocator_alloc(
  37                 struct lttng_index_allocator *allocator,
  38                 uint64_t *index);
  39
  40 /*
  41  * Release a slot by index. The slot will be re-used by the index allocator
  42  * in future 'alloc' calls.
  43  */
  44 enum lttng_index_allocator_status lttng_index_allocator_release(
  45                 struct lttng_index_allocator *allocator, uint64_t index);
  46
  47 /*
  48  * Destroy an index allocator.
  49  */
  50 void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator);
  51
  52 #endif /* _COMMON_INDEX_ALLOCATOR_H */