[lttng-tools.git] / src / common / buffer-view.hpp

/*
 * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */

#ifndef LTTNG_BUFFER_VIEW_H
#define LTTNG_BUFFER_VIEW_H

#include <common/macros.hpp>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

struct lttng_dynamic_buffer;

struct lttng_buffer_view {
	const char *data;
	size_t size;
};

/**
 * Return a buffer view referencing a subset of the memory referenced by a raw
 * pointer.
 *
 * @src		Source buffer to reference
 * @offset	Offset to apply to the source memory buffer
 * @len		Length of the memory contents to reference.
 *
 * Note that a buffer view never assumes the ownership of the memory it
 * references.
 */
struct lttng_buffer_view lttng_buffer_view_init(
		const char *src, size_t offset, ptrdiff_t len);

/**
 * Checks if a buffer view is safe to access.
 *
 * After calling the buffer view creation functions, callers should verify
 * if the resquested length (if any is explicitly provided) could be mapped
 * to a new view.
 *
 * @view	Buffer view to validate
 */
bool lttng_buffer_view_is_valid(const struct lttng_buffer_view *view);

/**
 * Return a buffer view referencing a subset of the memory referenced by another
 * view.
 *
 * @src		Source view to reference
 * @offset	Offset to apply to the source memory content
 * @len		Length of the memory contents to reference. Passing -1 will
 *		cause the view to reference the whole view from the offset
 *		provided.
 *
 * Note that a buffer view never assumes the ownership of the memory it
 * references.
 */
struct lttng_buffer_view lttng_buffer_view_from_view(
		const struct lttng_buffer_view *src, size_t offset,
		ptrdiff_t len);

/**
 * Return a buffer view referencing a subset of the memory referenced by a
 * dynamic buffer.
 *
 * @src		Source dynamic buffer to reference
 * @offset	Offset to apply to the source memory content
 * @len		Length of the memory contents to reference. Passing -1 will
 *		cause the view to reference the whole dynamic buffer from the
 *		offset provided.
 *
 * Note that a buffer view never assumes the ownership of the memory it
 * references.
 */
struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
		const struct lttng_dynamic_buffer *src, size_t offset,
		ptrdiff_t len);

/**
 * Verify that `buf` contains a string starting at `str` of length
 * `len_with_null_terminator`.
 *
 * @buf				The buffer view
 * @str				The start of the string
 * @len_with_null_terminator	Expected length of the string, including the
 * 				NULL terminator.
 */
bool lttng_buffer_view_contains_string(const struct lttng_buffer_view *buf,
		const char *str,
		size_t len_with_null_terminator);

#endif /* LTTNG_BUFFER_VIEW_H */
Commit	Line	Data
	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.hpp>
	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	struct lttng_buffer_view lttng_buffer_view_init(
	35	const char *src, size_t offset, ptrdiff_t len);
	36
	37	/**
	38	* Checks if a buffer view is safe to access.
	39	*
	40	* After calling the buffer view creation functions, callers should verify
	41	* if the resquested length (if any is explicitly provided) could be mapped
	42	* to a new view.
	43	*
	44	* @view Buffer view to validate
	45	*/
	46	bool lttng_buffer_view_is_valid(const struct lttng_buffer_view *view);
	47
	48	/**
	49	* Return a buffer view referencing a subset of the memory referenced by another
	50	* view.
	51	*
	52	* @src Source view to reference
	53	* @offset Offset to apply to the source memory content
	54	* @len Length of the memory contents to reference. Passing -1 will
	55	* cause the view to reference the whole view from the offset
	56	* provided.
	57	*
	58	* Note that a buffer view never assumes the ownership of the memory it
	59	* references.
	60	*/
	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	struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
	79	const struct lttng_dynamic_buffer *src, size_t offset,
	80	ptrdiff_t len);
	81
	82	/**
	83	* Verify that `buf` contains a string starting at `str` of length
	84	* `len_with_null_terminator`.
	85	*
	86	* @buf The buffer view
	87	* @str The start of the string
	88	* @len_with_null_terminator Expected length of the string, including the
	89	* NULL terminator.
	90	*/
	91	bool lttng_buffer_view_contains_string(const struct lttng_buffer_view *buf,
	92	const char *str,
	93	size_t len_with_null_terminator);
	94
	95	#endif /* LTTNG_BUFFER_VIEW_H */