src/common/buffer-view.h

   1 /*
   2  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_BUFFER_VIEW_H
   9 #define LTTNG_BUFFER_VIEW_H
  10
  11 #include <stddef.h>
  12 #include <stdint.h>
  13 #include <common/macros.h>
  14
  15 struct lttng_dynamic_buffer;
  16
  17 struct lttng_buffer_view {
  18         const char *data;
  19         size_t size;
  20 };
  21
  22 /**
  23  * Return a buffer view referencing a subset of the memory referenced by a raw
  24  * pointer.
  25  *
  26  * @src         Source buffer to reference
  27  * @offset      Offset to apply to the source memory buffer
  28  * @len         Length of the memory contents to reference.
  29  *
  30  * Note that a buffer view never assumes the ownership of the memory it
  31  * references.
  32  */
  33 LTTNG_HIDDEN
  34 struct lttng_buffer_view lttng_buffer_view_init(
  35                 const char *src, size_t offset, ptrdiff_t len);
  36
  37 /**
  38  * Return a buffer view referencing a subset of the memory referenced by another
  39  * view.
  40  *
  41  * @src         Source view to reference
  42  * @offset      Offset to apply to the source memory content
  43  * @len         Length of the memory contents to reference. Passing -1 will
  44  *              cause the view to reference the whole view from the offset
  45  *              provided.
  46  *
  47  * Note that a buffer view never assumes the ownership of the memory it
  48  * references.
  49  */
  50 LTTNG_HIDDEN
  51 struct lttng_buffer_view lttng_buffer_view_from_view(
  52                 const struct lttng_buffer_view *src, size_t offset,
  53                 ptrdiff_t len);
  54
  55 /**
  56  * Return a buffer view referencing a subset of the memory referenced by a
  57  * dynamic buffer.
  58  *
  59  * @src         Source dynamic buffer to reference
  60  * @offset      Offset to apply to the source memory content
  61  * @len         Length of the memory contents to reference. Passing -1 will
  62  *              cause the view to reference the whole dynamic buffer from the
  63  *              offset provided.
  64  *
  65  * Note that a buffer view never assumes the ownership of the memory it
  66  * references.
  67  */
  68 LTTNG_HIDDEN
  69 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  70                 const struct lttng_dynamic_buffer *src, size_t offset,
  71                 ptrdiff_t len);
  72
  73 #endif /* LTTNG_BUFFER_VIEW_H */