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