src/common/buffer-view.h

   1 /*
   2  * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this program; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18 #ifndef LTTNG_BUFFER_VIEW_H
  19 #define LTTNG_BUFFER_VIEW_H
  20
  21 #include <stddef.h>
  22 #include <stdint.h>
  23 #include <common/macros.h>
  24
  25 struct lttng_dynamic_buffer;
  26
  27 struct lttng_buffer_view {
  28         const char *data;
  29         size_t size;
  30 };
  31
  32 /**
  33  * Return a buffer view referencing a subset of the memory referenced by another
  34  * view.
  35  *
  36  * @src         Source view to reference
  37  * @offset      Offset to apply to the source memory content
  38  * @len         Length of the memory contents to reference. Passing -1 will
  39  *              cause the view to reference the whole view from the offset
  40  *              provided.
  41  *
  42  * Note that a buffer view never assumes the ownership of the memory it
  43  * references.
  44  */
  45 LTTNG_HIDDEN
  46 struct lttng_buffer_view lttng_buffer_view_from_view(
  47                 const struct lttng_buffer_view *src, size_t offset,
  48                 ptrdiff_t len);
  49
  50 /**
  51  * Return a buffer view referencing a subset of the memory referenced by a
  52  * dynamic buffer.
  53  *
  54  * @src         Source dynamic buffer to reference
  55  * @offset      Offset to apply to the source memory content
  56  * @len         Length of the memory contents to reference. Passing -1 will
  57  *              cause the view to reference the whole dynamic buffer from the
  58  *              offset provided.
  59  *
  60  * Note that a buffer view never assumes the ownership of the memory it
  61  * references.
  62  */
  63 LTTNG_HIDDEN
  64 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  65                 const struct lttng_dynamic_buffer *src, size_t offset,
  66                 ptrdiff_t len);
  67
  68 #endif /* LTTNG_BUFFER_VIEW_H */