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 #include <lttng/lttng-export.h>
  13
  14 #ifdef __cplusplus
  15 extern "C" {
  16 #endif
  17
  18 struct lttng_index_allocator;
  19
  20 enum lttng_index_allocator_status {
  21         LTTNG_INDEX_ALLOCATOR_STATUS_OK,
  22         LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY,
  23         LTTNG_INDEX_ALLOCATOR_STATUS_ERROR,
  24 };
  25
  26 /*
  27  * Create an index allocator of `index_count` slots.
  28  */
  29 LTTNG_EXPORT struct lttng_index_allocator *lttng_index_allocator_create(
  30                 uint64_t index_count);
  31
  32 /*
  33  * Get the number of indexes currently in use.
  34  */
  35 LTTNG_EXPORT uint64_t lttng_index_allocator_get_index_count(
  36         struct lttng_index_allocator *allocator);
  37
  38 /*
  39  * Allocate (i.e. reserve) a slot.
  40  */
  41 LTTNG_EXPORT enum lttng_index_allocator_status lttng_index_allocator_alloc(
  42                 struct lttng_index_allocator *allocator,
  43                 uint64_t *index);
  44
  45 /*
  46  * Release a slot by index. The slot will be re-used by the index allocator
  47  * in future 'alloc' calls.
  48  */
  49 LTTNG_EXPORT enum lttng_index_allocator_status lttng_index_allocator_release(
  50                 struct lttng_index_allocator *allocator, uint64_t index);
  51
  52 /*
  53  * Destroy an index allocator.
  54  */
  55 LTTNG_EXPORT void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator);
  56
  57 #ifdef __cplusplus
  58 }
  59 #endif
  60
  61 #endif /* _COMMON_INDEX_ALLOCATOR_H */