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interval_tree.h
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interval_tree.h
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_INTERVAL_TREE_H
#define _LINUX_INTERVAL_TREE_H
#include <linux/rbtree.h>
struct interval_tree_node {
struct rb_node rb;
unsigned long start; /* Start of interval */
unsigned long last; /* Last location _in_ interval */
unsigned long __subtree_last;
};
extern void
interval_tree_insert(struct interval_tree_node *node,
struct rb_root_cached *root);
extern void
interval_tree_remove(struct interval_tree_node *node,
struct rb_root_cached *root);
extern struct interval_tree_node *
interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
extern struct interval_tree_node *
interval_tree_iter_next(struct interval_tree_node *node,
unsigned long start, unsigned long last);
/**
* struct interval_tree_span_iter - Find used and unused spans.
* @start_hole: Start of an interval for a hole when is_hole == 1
* @last_hole: Inclusive end of an interval for a hole when is_hole == 1
* @start_used: Start of a used interval when is_hole == 0
* @last_used: Inclusive end of a used interval when is_hole == 0
* @is_hole: 0 == used, 1 == is_hole, -1 == done iteration
*
* This iterator travels over spans in an interval tree. It does not return
* nodes but classifies each span as either a hole, where no nodes intersect, or
* a used, which is fully covered by nodes. Each iteration step toggles between
* hole and used until the entire range is covered. The returned spans always
* fully cover the requested range.
*
* The iterator is greedy, it always returns the largest hole or used possible,
* consolidating all consecutive nodes.
*
* Use interval_tree_span_iter_done() to detect end of iteration.
*/
struct interval_tree_span_iter {
/* private: not for use by the caller */
struct interval_tree_node *nodes[2];
unsigned long first_index;
unsigned long last_index;
/* public: */
union {
unsigned long start_hole;
unsigned long start_used;
};
union {
unsigned long last_hole;
unsigned long last_used;
};
int is_hole;
};
void interval_tree_span_iter_first(struct interval_tree_span_iter *state,
struct rb_root_cached *itree,
unsigned long first_index,
unsigned long last_index);
void interval_tree_span_iter_advance(struct interval_tree_span_iter *iter,
struct rb_root_cached *itree,
unsigned long new_index);
void interval_tree_span_iter_next(struct interval_tree_span_iter *state);
static inline bool
interval_tree_span_iter_done(struct interval_tree_span_iter *state)
{
return state->is_hole == -1;
}
#define interval_tree_for_each_span(span, itree, first_index, last_index) \
for (interval_tree_span_iter_first(span, itree, \
first_index, last_index); \
!interval_tree_span_iter_done(span); \
interval_tree_span_iter_next(span))
#endif /* _LINUX_INTERVAL_TREE_H */