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