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Diffstat (limited to 'sys/netinet/ipfw/dn_heap.h')
| -rw-r--r-- | sys/netinet/ipfw/dn_heap.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/sys/netinet/ipfw/dn_heap.h b/sys/netinet/ipfw/dn_heap.h new file mode 100644 index 0000000..a663f91 --- /dev/null +++ b/sys/netinet/ipfw/dn_heap.h @@ -0,0 +1,191 @@ +/*- + * Copyright (c) 1998-2010 Luigi Rizzo, Universita` di Pisa + * All rights reserved + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * Binary heap and hash tables, header file + * + * $FreeBSD$ + */ + +#ifndef _IP_DN_HEAP_H +#define _IP_DN_HEAP_H + +#define DN_KEY_LT(a,b) ((int64_t)((a)-(b)) < 0) +#define DN_KEY_LEQ(a,b) ((int64_t)((a)-(b)) <= 0) + +/* + * This module implements a binary heap supporting random extraction. + * + * A heap entry contains an uint64_t key and a pointer to object. + * DN_KEY_LT(a,b) returns true if key 'a' is smaller than 'b' + * + * The heap is a struct dn_heap plus a dynamically allocated + * array of dn_heap_entry entries. 'size' represents the size of + * the array, 'elements' count entries in use. The topmost + * element has the smallest key. + * The heap supports ordered insert, and extract from the top. + * To extract an object from the middle of the heap, we the object + * must reserve an 'int32_t' to store the position of the object + * in the heap itself, and the location of this field must be + * passed as an argument to heap_init() -- use -1 if the feature + * is not used. + */ +struct dn_heap_entry { + uint64_t key; /* sorting key, smallest comes first */ + void *object; /* object pointer */ +}; + +struct dn_heap { + int size; /* the size of the array */ + int elements; /* elements in use */ + int ofs; /* offset in the object of heap index */ + struct dn_heap_entry *p; /* array of "size" entries */ +}; + +enum { + HEAP_SCAN_DEL = 1, + HEAP_SCAN_END = 2, +}; + +/* + * heap_init() reinitializes the heap setting the size and the offset + * of the index for random extraction (use -1 if not used). + * The 'elements' counter is set to 0. + * + * SET_HEAP_OFS() indicates where, in the object, is stored the index + * for random extractions from the heap. + * + * heap_free() frees the memory associated to a heap. + * + * heap_insert() adds a key-pointer pair to the heap + * + * HEAP_TOP() returns a pointer to the top element of the heap, + * but makes no checks on its existance (XXX should we change ?) + * + * heap_extract() removes the entry at the top, returing the pointer. + * (the key should have been read before). + * + * heap_scan() invokes a callback on each entry of the heap. + * The callback can return a combination of HEAP_SCAN_DEL and + * HEAP_SCAN_END. HEAP_SCAN_DEL means the current element must + * be removed, and HEAP_SCAN_END means to terminate the scan. + * heap_scan() returns the number of elements removed. + * Because the order is not guaranteed, we should use heap_scan() + * only as a last resort mechanism. + */ +#define HEAP_TOP(h) ((h)->p) +#define SET_HEAP_OFS(h, n) do { (h)->ofs = n; } while (0) +int heap_init(struct dn_heap *h, int size, int ofs); +int heap_insert(struct dn_heap *h, uint64_t key1, void *p); +void heap_extract(struct dn_heap *h, void *obj); +void heap_free(struct dn_heap *h); +int heap_scan(struct dn_heap *, int (*)(void *, uintptr_t), uintptr_t); + +/*------------------------------------------------------ + * This module implements a generic hash table with support for + * running callbacks on the entire table. To avoid allocating + * memory during hash table operations, objects must reserve + * space for a link field. XXX if the heap is moderately full, + * an SLIST suffices, and we can tolerate the cost of a hash + * computation on each removal. + * + * dn_ht_init() initializes the table, setting the number of + * buckets, the offset of the link field, the main callbacks. + * Callbacks are: + * + * hash(key, flags, arg) called to return a bucket index. + * match(obj, key, flags, arg) called to determine if key + * matches the current 'obj' in the heap + * new(key, flags, arg) optional, used to allocate a new + * object during insertions. + * + * dn_ht_free() frees the heap or unlink elements. + * DNHT_REMOVE unlink elements, 0 frees the heap. + * You need two calls to do both. + * + * dn_ht_find() is the main lookup function, which can also be + * used to insert or delete elements in the hash table. + * The final 'arg' is passed to all callbacks. + * + * dn_ht_scan() is used to invoke a callback on all entries of + * the heap, or possibly on just one bucket. The callback + * is invoked with a pointer to the object, and must return + * one of DNHT_SCAN_DEL or DNHT_SCAN_END to request the + * removal of the object from the heap and the end of the + * scan, respectively. + * + * dn_ht_scan_bucket() is similar to dn_ht_scan(), except that it scans + * only the specific bucket of the table. The bucket is a in-out + * parameter and return a valid bucket number if the original + * is invalid. + * + * A combination of flags can be used to modify the operation + * of the dn_ht_find(), and of the callbacks: + * + * DNHT_KEY_IS_OBJ means the key is the object pointer. + * It is usally of interest for the hash and match functions. + * + * DNHT_MATCH_PTR during a lookup, match pointers instead + * of calling match(). Normally used when removing specific + * entries. Does not imply KEY_IS_OBJ as the latter _is_ used + * by the match function. + * + * DNHT_INSERT insert the element if not found. + * Calls new() to allocates a new object unless + * DNHT_KEY_IS_OBJ is set. + * + * DNHT_UNIQUE only insert if object not found. + * XXX should it imply DNHT_INSERT ? + * + * DNHT_REMOVE remove objects if we find them. + */ +struct dn_ht; /* should be opaque */ + +struct dn_ht *dn_ht_init(struct dn_ht *, int buckets, int ofs, + uint32_t (*hash)(uintptr_t, int, void *), + int (*match)(void *, uintptr_t, int, void *), + void *(*new)(uintptr_t, int, void *)); +void dn_ht_free(struct dn_ht *, int flags); + +void *dn_ht_find(struct dn_ht *, uintptr_t, int, void *); +int dn_ht_scan(struct dn_ht *, int (*)(void *, void *), void *); +int dn_ht_scan_bucket(struct dn_ht *, int * , int (*)(void *, void *), void *); +int dn_ht_entries(struct dn_ht *); + +enum { /* flags values. + * first two are returned by the scan callback to indicate + * to delete the matching element or to end the scan + */ + DNHT_SCAN_DEL = 0x0001, + DNHT_SCAN_END = 0x0002, + DNHT_KEY_IS_OBJ = 0x0004, /* key is the obj pointer */ + DNHT_MATCH_PTR = 0x0008, /* match by pointer, not match() */ + DNHT_INSERT = 0x0010, /* insert if not found */ + DNHT_UNIQUE = 0x0020, /* report error if already there */ + DNHT_REMOVE = 0x0040, /* remove on find or dn_ht_free */ +}; + +#endif /* _IP_DN_HEAP_H */ |
