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#ifndef CHAIN_H

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#define CHAIN_H

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/**

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 * Defines a generalized "chain of things" behaviour.

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 *

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 * The structure of this is a CHAIN_LIST, which contains a number of CHAIN_HEAD items, which then contain a number of

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 * induvidual items.

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 */

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#include "error.h"

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#include <sys/queue.h>

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/**

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 * The chain header.

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 */

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struct chain_head {

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    const void *chain;

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    void *arg;

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    STAILQ_ENTRY(chain_head) node;

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};

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/**

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 * @struct chain_list

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 *

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 * The chain list

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 */

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STAILQ_HEAD(chain_list, chain_head);

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/**

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 * Initialize a `struct chain_list`

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 */

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#define CHAIN_INIT(list_ptr) STAILQ_INIT(list_ptr)

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/**

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 * Add an item onto the end of a chain_list

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 */

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err_t chain_add (struct chain_list *list, const void *chain, void *arg);

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/**

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 * Iterate over the contents of a chain_list

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 *

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 * struct chain_list *list = ...;

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 * struct chain_head *head;

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 * struct foo *foo;

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 *

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 *  CHAIN_FOREACH(list, head) {

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 *      for (foo = head->chain; foo->bar; foo++) {

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 *          foo->bar(foo, head->arg);

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 *      }

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 *  }

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 */

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#define CHAIN_FOREACH(list_ptr, head_ptr) STAILQ_FOREACH(head_ptr, list_ptr, node)

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/**

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 * Free a chain_list

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 */

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void chain_free (struct chain_list *list);

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#endif