1 files changed, 104 insertions, 0 deletions
diff --git a/include/osmocom/core/stat_item.h b/include/osmocom/core/stat_item.h
new file mode 100644
index 00000000..e166579f
--- /dev/null
+++ b/include/osmocom/core/stat_item.h
@@ -0,0 +1,104 @@
+#pragma once
+
+/*! \defgroup stat_item Statistics value item
+ *  @{
+ */
+
+/*! \file stat_item.h */
+
+#include <stdint.h>
+
+#include <osmocom/core/linuxlist.h>
+
+struct stat_item_desc;
+
+/*! \brief data we keep for each actual value */
+struct stat_item {
+	const struct stat_item_desc *desc;
+	/*! \brief the index of the freshest value */
+	int32_t last_value_index;
+	/*! \brief offset to the freshest value in the value fifo */
+	int16_t last_offs;
+	/*! \brief value fifo */
+	int32_t values[0];
+};
+
+/*! \brief statistics value description */
+struct stat_item_desc {
+	const char *name;	/*!< \brief name of the item */
+	const char *description;/*!< \brief description of the item */
+	const char *unit;	/*!< \brief unit of a value */
+	unsigned int num_values;/*!< \brief number of values to store */
+	int32_t default_value;
+};
+
+/*! \brief description of a statistics value group */
+struct stat_item_group_desc {
+	/*! \brief The prefix to the name of all values in this group */
+	const char *group_name_prefix;
+	/*! \brief The human-readable description of the group */
+	const char *group_description;
+	/*! \brief The number of values in this group */
+	const unsigned int num_items;
+	/*! \brief Pointer to array of value names */
+	const struct stat_item_desc *item_desc;
+};
+
+/*! \brief One instance of a counter group class */
+struct stat_item_group {
+	/*! \brief Linked list of all value groups in the system */
+	struct llist_head list;
+	/*! \brief Pointer to the counter group class */
+	const struct stat_item_group_desc *desc;
+	/*! \brief The index of this value group within its class */
+	unsigned int idx;
+	/*! \brief Actual counter structures below */
+	struct stat_item *items[0];
+};
+
+struct stat_item_group *stat_item_group_alloc(
+	void *ctx,
+	const struct stat_item_group_desc *desc,
+	unsigned int idx);
+
+void stat_item_group_free(struct stat_item_group *grp);
+
+void stat_item_set(struct stat_item *val, int32_t value);
+
+int stat_item_init(void *tall_ctx);
+
+struct stat_item_group *stat_item_get_group_by_name_idx(
+	const char *name, const unsigned int idx);
+
+const struct stat_item *stat_item_get_by_name(
+	const struct stat_item_group *valg, const char *name);
+
+/*! \brief Retrieve the next value from the stat_item object.
+ * If a new value has been set, it is returned. The idx is used to decide
+ * which value to return.
+ * On success, *idx is updated to refer to the next unread value. If
+ * values have been missed due to FIFO overflow, *idx is incremented by
+ * (1 + num_lost).
+ * This way, the stat_item object can be kept stateless from the reader's
+ * perspective and therefore be used by several backends simultaneously.
+ *
+ * \param val	the stat_item object
+ * \param idx	identifies the next value to be read
+ * \param value	a pointer to store the value
+ * \returns  the increment of the index (0: no value has been read,
+ *           1: one value has been taken,
+ *           (1+n): n values have been skipped, one has been taken)
+ */
+int stat_item_get_next(const struct stat_item *val, int32_t *idx, int32_t *value);
+
+/*! \brief Get the last (freshest) value */
+static int32_t stat_item_get_last(const struct stat_item *val);
+
+/*! \brief Skip all values of the item and update idx accordingly */
+int stat_item_discard(const struct stat_item *val, int32_t *idx);
+
+static inline int32_t stat_item_get_last(const struct stat_item *val)
+{
+	return val->values[val->last_offs];
+}
+/*! @} */