Add lttng_buffer_view util

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

diff --git a/src/common/buffer-view.c b/src/common/buffer-view.c
new file mode 100644 (file)
index 0000000..8ff1539
--- /dev/null
+++ b/src/common/buffer-view.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License, version 2.1 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <common/buffer-view.h>
+#include <common/dynamic-buffer.h>
+#include <common/macros.h>
+#include <common/error.h>
+#include <assert.h>
+
+struct lttng_buffer_view lttng_buffer_view_from_view(
+               const struct lttng_buffer_view *src, size_t offset,
+               ptrdiff_t len)
+{
+       struct lttng_buffer_view view = { .data = NULL, .size = 0 };
+
+       assert(src);
+
+       if (offset > src->size) {
+               ERR("Attempt to create buffer view with invalid offset");
+               goto end;
+       }
+
+       if (len != -1 && len > (src->size - offset)) {
+               ERR("Attempt to create buffer view with invalid length");
+               goto end;
+       }
+
+       view.data = src->data + offset;
+       view.size = len == -1 ? (src->size - offset) : len;
+end:
+       return view;
+}
+
+struct lttng_buffer_view lttng_buffer_view_from_dynamic_buffer(
+               const struct lttng_dynamic_buffer *src, size_t offset,
+               ptrdiff_t len)
+{
+       struct lttng_buffer_view view = { .data = NULL, .size = 0 };
+
+       assert(src);
+
+       if (offset > src->size) {
+               ERR("Attempt to create buffer view with invalid offset");
+               goto end;
+       }
+
+       if (len != -1 && len > (src->size - offset)) {
+               ERR("Attempt to create buffer view with invalid length");
+               goto end;
+       }
+
+       view.data = src->data + offset;
+       view.size = len == -1 ? (src->size - offset) : len;
+end:
+       return view;
+}