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 a raw
  34  * pointer.
  35  *
  36  * @src         Source buffer to reference
  37  * @offset      Offset to apply to the source memory buffer
  38  * @len         Length of the memory contents to reference.
  39  *
  40  * Note that a buffer view never assumes the ownership of the memory it
  41  * references.
  42  */
  43 LTTNG_HIDDEN
  44 struct lttng_buffer_view lttng_buffer_view_init(
  45                 const char *src, size_t offset, ptrdiff_t len);
  46
  47 /**
  48  * Return a buffer view referencing a subset of the memory referenced by another
  49  * view.
  50  *
  51  * @src         Source view to reference
  52  * @offset      Offset to apply to the source memory content
  53  * @len         Length of the memory contents to reference. Passing -1 will
  54  *              cause the view to reference the whole view from the offset
  55  *              provided.
  56  *
  57  * Note that a buffer view never assumes the ownership of the memory it
  58  * references.
  59  */
  60 LTTNG_HIDDEN
  61 struct lttng_buffer_view lttng_buffer_view_from_view(
  62                 const struct lttng_buffer_view *src, size_t offset,
  63                 ptrdiff_t len);
  64
  65 /**
  66  * Return a buffer view referencing a subset of the memory referenced by a
  67  * dynamic buffer.
  68  *
  69  * @src         Source dynamic buffer to reference
  70  * @offset      Offset to apply to the source memory content
  71  * @len         Length of the memory contents to reference. Passing -1 will
  72  *              cause the view to reference the whole dynamic buffer from the
  73  *              offset provided.
  74  *
  75  * Note that a buffer view never assumes the ownership of the memory it
  76  * references.
  77  */
  78 LTTNG_HIDDEN
  79 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  80                 const struct lttng_dynamic_buffer *src, size_t offset,
  81                 ptrdiff_t len);
  82
  83 #endif /* LTTNG_BUFFER_VIEW_H */