kdtree.h

/*
 * Copyright (C) 2017, Leo Ma <begeekmyfriend@gmail.com>
 */

#ifndef _KD_TREE_H
#define _KD_TREE_H

#define KDTREE_MAX_LEVEL 64
#define KDTREE_LEFT_INDEX 0
#define KDTREE_RIGHT_INDEX 1

typedef struct knn_list {
        struct kdnode *node;
        double distance;
        struct knn_list *prev;
        struct knn_list *next;
} knn_list_t;

typedef struct kdnode {
        long coord_index;
        double *coord;
        struct kdnode *left;
        struct kdnode *right;
        int r;
} kdnode_t;

typedef struct kdtree {
        struct kdnode *root;
        size_t count;
        size_t capacity;
        double *coords;
        double **coord_table;
        long *coord_indexes;
        unsigned char *coord_deleted;
        unsigned char *coord_passed;
        struct knn_list knn_list_head;
        int dim;
        int knn_num;
} kdtree_t;

struct kdtree *kdtree_init(int dim);
void kdtree_insert(struct kdtree *tree, double *coord);
void kdtree_rebuild(struct kdtree *tree);
void kdtree_knn_search(struct kdtree *tree, double *coord, int k);
void kdtree_destroy(struct kdtree *tree);
void kdtree_dump(struct kdtree *tree);

#endif /* _KD_TREE_H */