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 <common/macros.h>
  12 #include <stdbool.h>
  13 #include <stddef.h>
  14 #include <stdint.h>
  15
  16 struct lttng_dynamic_buffer;
  17
  18 struct lttng_buffer_view {
  19         const char *data;
  20         size_t size;
  21 };
  22
  23 /**
  24  * Return a buffer view referencing a subset of the memory referenced by a raw
  25  * pointer.
  26  *
  27  * @src         Source buffer to reference
  28  * @offset      Offset to apply to the source memory buffer
  29  * @len         Length of the memory contents to reference.
  30  *
  31  * Note that a buffer view never assumes the ownership of the memory it
  32  * references.
  33  */
  34 LTTNG_HIDDEN
  35 struct lttng_buffer_view lttng_buffer_view_init(
  36                 const char *src, size_t offset, ptrdiff_t len);
  37
  38 /**
  39  * Return a buffer view referencing a subset of the memory referenced by another
  40  * view.
  41  *
  42  * @src         Source view to reference
  43  * @offset      Offset to apply to the source memory content
  44  * @len         Length of the memory contents to reference. Passing -1 will
  45  *              cause the view to reference the whole view from the offset
  46  *              provided.
  47  *
  48  * Note that a buffer view never assumes the ownership of the memory it
  49  * references.
  50  */
  51 LTTNG_HIDDEN
  52 struct lttng_buffer_view lttng_buffer_view_from_view(
  53                 const struct lttng_buffer_view *src, size_t offset,
  54                 ptrdiff_t len);
  55
  56 /**
  57  * Return a buffer view referencing a subset of the memory referenced by a
  58  * dynamic buffer.
  59  *
  60  * @src         Source dynamic buffer to reference
  61  * @offset      Offset to apply to the source memory content
  62  * @len         Length of the memory contents to reference. Passing -1 will
  63  *              cause the view to reference the whole dynamic buffer from the
  64  *              offset provided.
  65  *
  66  * Note that a buffer view never assumes the ownership of the memory it
  67  * references.
  68  */
  69 LTTNG_HIDDEN
  70 struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
  71                 const struct lttng_dynamic_buffer *src, size_t offset,
  72                 ptrdiff_t len);
  73
  74 /**
  75  * Verify that `buf` contains a string starting at `str` of length
  76  * `len_with_null_terminator`.
  77  *
  78  * @buf                         The buffer view
  79  * @str                         The start of the string
  80  * @len_with_null_terminator    Expected length of the string, including the
  81  *                              NULL terminator.
  82  */
  83 LTTNG_HIDDEN
  84 bool lttng_buffer_view_contains_string(const struct lttng_buffer_view *buf,
  85                 const char *str,
  86                 size_t len_with_null_terminator);
  87
  88 #endif /* LTTNG_BUFFER_VIEW_H */