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/*
* radtree -- generic radix tree for binary strings.
*
* Copyright (c) 2010, NLnet Labs. See LICENSE for license.
*/
#ifndef RADTREE_H
#define RADTREE_H
struct radnode;
struct region;
/** length of the binary string */
typedef uint16_t radstrlen_type;
/**
* The radix tree
*
* The elements are stored based on binary strings(0-255) of a given length.
* They are sorted, a prefix is sorted before its suffixes.
* If you want to know the key string, you should store it yourself, the
* tree stores it in the parts necessary for lookup.
* For binary strings for domain names see the radname routines.
*/
struct radtree {
/** root node in tree */
struct radnode* root;
/** count of number of elements */
size_t count;
/** region for allocation */
struct region* region;
};
/**
* A radix tree lookup node.
* The array is malloced separately from the radnode.
*/
struct radnode {
/** data element associated with the binary string up to this node */
void* elem;
/** parent node (NULL for the root) */
struct radnode* parent;
/** index in the parent lookup array */
uint8_t pidx;
/** offset of the lookup array, add to [i] for lookups */
uint8_t offset;
/** length of the lookup array */
uint16_t len;
/** capacity of the lookup array (can be larger than length) */
uint16_t capacity;
/** the lookup array by [byte-offset] */
struct radsel* array;
};
/**
* radix select edge in array
*/
struct radsel {
/** additional string after the selection-byte for this edge. */
uint8_t* str;
/** length of the additional string for this edge */
radstrlen_type len;
/** node that deals with byte+str */
struct radnode* node;
};
/**
* Create new radix tree
* @param region: where to allocate the tree.
* @return new tree or NULL on alloc failure.
*/
struct radtree* radix_tree_create(struct region* region);
/**
* Init new radix tree.
* @param rt: radix tree to be initialized.
*/
void radix_tree_init(struct radtree* rt);
/**
* Delete intermediate nodes from radix tree
* @param rt: radix tree to be initialized.
*/
void radix_tree_clear(struct radtree* rt);
/**
* Delete radix tree.
* @param rt: radix tree to be deleted.
*/
void radix_tree_delete(struct radtree* rt);
/**
* Insert element into radix tree.
* @param rt: the radix tree.
* @param key: key string.
* @param len: length of key.
* @param elem: pointer to element data.
* @return NULL on failure - out of memory.
* NULL on failure - duplicate entry.
* On success the new radix node for this element.
*/
struct radnode* radix_insert(struct radtree* rt, uint8_t* k,
radstrlen_type len, void* elem);
/**
* Delete element from radix tree.
* @param rt: the radix tree.
* @param n: radix node for that element.
* if NULL, nothing is deleted.
*/
void radix_delete(struct radtree* rt, struct radnode* n);
/**
* Find radix element in tree.
* @param rt: the radix tree.
* @param key: key string.
* @param len: length of key.
* @return the radix node or NULL if not found.
*/
struct radnode* radix_search(struct radtree* rt, uint8_t* k,
radstrlen_type len);
/**
* Find radix element in tree, and if not found, find the closest smaller or
* equal element in the tree.
* @param rt: the radix tree.
* @param key: key string.
* @param len: length of key.
* @param result: returns the radix node or closest match (NULL if key is
* smaller than the smallest key in the tree).
* @return true if exact match, false if no match.
*/
int radix_find_less_equal(struct radtree* rt, uint8_t* k, radstrlen_type len,
struct radnode** result);
/**
* Return the first (smallest) element in the tree.
* @param rt: the radix tree.
* @return: first node or NULL if none.
*/
struct radnode* radix_first(struct radtree* rt);
/**
* Return the last (largest) element in the tree.
* @param rt: the radix tree.
* @return: last node or NULL if none.
*/
struct radnode* radix_last(struct radtree* rt);
/**
* Return the next element.
* @param n: the element to go from.
* @return: next node or NULL if none.
*/
struct radnode* radix_next(struct radnode* n);
/**
* Return the previous element.
* @param n: the element to go from.
* @return: prev node or NULL if none.
*/
struct radnode* radix_prev(struct radnode* n);
/*
* Perform a walk through all elements of the tree.
* node: variable of type struct radnode*.
* tree: pointer to the tree.
* for(node=radix_first(tree); node; node=radix_next(node))
*/
/**
* Create a binary string to represent a domain name
* @param k: string buffer to store into
* @param len: output length, initially, the max, output the result.
* @param dname: the domain name to convert, in wireformat.
* @param dlen: length of space for dname.
*/
void radname_d2r(uint8_t* k, radstrlen_type* len, const uint8_t* dname,
size_t dlen);
/**
* Convert a binary string back to a domain name.
* @param k: the binary string.
* @param len: length of k.
* @param dname: buffer to store domain name into.
* @param dlen: length of dname (including root label).
*/
void radname_r2d(uint8_t* k, radstrlen_type len, uint8_t* dname, size_t* dlen);
/**
* Search the radix tree using a domain name.
* The name is internally converted to a radname.
* @param rt: tree
* @param d: domain name, no compression pointers allowed.
* @param max: max length to go from d.
* @return NULL on parse error or if not found.
*/
struct radnode* radname_search(struct radtree* rt, const uint8_t* d,
size_t max);
/**
* Find radix element in tree by domain name, and if not found,
* find the closest smaller or equal element in the tree.
* The name is internally converted to a radname (same sorting order).
* @param rt: the radix tree.
* @param d: domain name, no compression pointers allowed.
* @param max: max length to go from d.
* @param result: returns the radix node or closest match (NULL if key is
* smaller than the smallest key in the tree).
* could result in NULL on a parse error as well (with return false).
* @return true if exact match, false if no match.
*/
int radname_find_less_equal(struct radtree* rt, const uint8_t* d, size_t max,
struct radnode** result);
/**
* Insert radix element by domain name.
* @param rt: the radix tree
* @param d: domain name, no compression pointers.
* @param max: max length from d.
* @param elem: the element pointer to insert.
* @return NULL on failure - out of memory.
* NULL on failure - duplicate entry.
* NULL on failure - parse error.
* On success the radix node for this element.
*/
struct radnode* radname_insert(struct radtree* rt, const uint8_t* d,
size_t max, void* elem);
/**
* Delete element by domain name from radix tree.
* @param rt: the radix tree.
* @param d: the domain name. If it is not in the tree nothing happens.
* @param max: max length.
*/
void radname_delete(struct radtree* rt, const uint8_t* d, size_t max);
/** number of bytes in common in strings */
radstrlen_type bstr_common_ext(uint8_t* x, radstrlen_type xlen, uint8_t* y,
radstrlen_type ylen);
/** true if one is prefix of the other */
int bstr_is_prefix_ext(uint8_t* p, radstrlen_type plen, uint8_t* x,
radstrlen_type xlen);
#endif /* RADTREE_H */
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