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78 lines
1.9 KiB
C
78 lines
1.9 KiB
C
/*
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* Copyright (C) 2011 STRATO AG
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* written by Arne Jansen <sensille@gmx.net>
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* Distributed under the GNU GPL license version 2.
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*
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*/
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#ifndef __ULIST__
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#define __ULIST__
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/*
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* ulist is a generic data structure to hold a collection of unique u64
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* values. The only operations it supports is adding to the list and
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* enumerating it.
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* It is possible to store an auxiliary value along with the key.
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*
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* The implementation is preliminary and can probably be sped up
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* significantly. A first step would be to store the values in an rbtree
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* as soon as ULIST_SIZE is exceeded.
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*/
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/*
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* number of elements statically allocated inside struct ulist
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*/
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#define ULIST_SIZE 16
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struct ulist_iterator {
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int i;
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};
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/*
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* element of the list
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*/
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struct ulist_node {
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u64 val; /* value to store */
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unsigned long aux; /* auxiliary value saved along with the val */
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};
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struct ulist {
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/*
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* number of elements stored in list
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*/
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unsigned long nnodes;
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/*
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* number of nodes we already have room for
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*/
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unsigned long nodes_alloced;
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/*
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* pointer to the array storing the elements. The first ULIST_SIZE
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* elements are stored inline. In this case the it points to int_nodes.
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* After exceeding ULIST_SIZE, dynamic memory is allocated.
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*/
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struct ulist_node *nodes;
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/*
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* inline storage space for the first ULIST_SIZE entries
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*/
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struct ulist_node int_nodes[ULIST_SIZE];
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};
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void ulist_init(struct ulist *ulist);
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void ulist_fini(struct ulist *ulist);
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void ulist_reinit(struct ulist *ulist);
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struct ulist *ulist_alloc(gfp_t gfp_mask);
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void ulist_free(struct ulist *ulist);
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int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
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gfp_t gfp_mask);
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int ulist_add_merge(struct ulist *ulist, u64 val, unsigned long aux,
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unsigned long *old_aux, gfp_t gfp_mask);
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struct ulist_node *ulist_next(struct ulist *ulist,
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struct ulist_iterator *uiter);
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#define ULIST_ITER_INIT(uiter) ((uiter)->i = 0)
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#endif
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