Common Trace Format 2 generation

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

diff --git a/src/common/buffer-view.hpp b/src/common/buffer-view.hpp
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+/*
+ * 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 */