172 lines
4.6 KiB
C
172 lines
4.6 KiB
C
/*
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* Copyright (C) 2005-2006 Martin Willi
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* Copyright (C) 2005 Jan Hutter
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* $Id$
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*/
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/**
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* @defgroup iterator iterator
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* @{ @ingroup utils
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*/
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#ifndef ITERATOR_H_
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#define ITERATOR_H_
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#include <library.h>
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typedef enum hook_result_t hook_result_t;
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/**
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* Return value of an iterator hook.
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*
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* Returning HOOK_AGAIN is useful to "inject" additional elements in an
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* iteration, HOOK_NEXT is the normal iterator behavior, and HOOK_SKIP may
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* be used to filter elements out.
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*/
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enum hook_result_t {
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/**
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* A value was placed in out, hook is called again with the same "in"
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*/
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HOOK_AGAIN,
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/**
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* A value was placed in out, hook is called again with next "in" (if any)
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*/
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HOOK_NEXT,
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/**
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* No value in out, call again with next "in" (if any)
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*/
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HOOK_SKIP,
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};
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/**
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* Iterator hook function prototype.
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*
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* @param param user supplied parameter
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* @param in the value the hook receives from the iterator
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* @param out the value supplied as a result to the iterator
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* @return a hook_result_t
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*/
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typedef hook_result_t (iterator_hook_t)(void *param, void *in, void **out);
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typedef struct iterator_t iterator_t;
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/**
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* Iterator interface, allows iteration over collections.
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*
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* iterator_t defines an interface for iterating over collections.
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* It allows searching, deleting, updating and inserting.
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*
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* @deprecated Use enumerator instead.
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*/
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struct iterator_t {
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/**
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* Return number of list items.
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*
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* @return number of list items
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*/
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int (*get_count) (iterator_t *this);
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/**
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* Iterate over all items.
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*
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* The easy way to iterate over items.
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*
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* @param value item
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* @return TRUE, if there was an element available, FALSE otherwise
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*/
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bool (*iterate) (iterator_t *this, void** value);
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/**
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* Hook a function into the iterator.
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*
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* Sometimes it is useful to hook in an iterator. The hook function is
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* called before any successful return of iterate(). It takes the
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* iterator value, may manipulate it (or the references object), and returns
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* the value that the iterate() function returns. Depending on the hook
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* return value, the hook is called again, called with next, or skipped.
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* A value of NULL deactivates the iterator hook.
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* If an iterator is hooked, only the iterate() method is valid,
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* all other methods behave undefined.
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*
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* @param hook iterator hook which manipulates the iterated value
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* @param param user supplied parameter to pass back to the hook
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*/
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void (*set_iterator_hook) (iterator_t *this, iterator_hook_t *hook,
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void *param);
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/**
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* Inserts a new item before the given iterator position.
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*
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* The iterator position is not changed after inserting
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*
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* @param item value to insert in list
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*/
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void (*insert_before) (iterator_t *this, void *item);
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/**
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* Inserts a new item after the given iterator position.
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*
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* The iterator position is not changed after inserting.
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*
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* @param this calling iterator
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* @param item value to insert in list
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*/
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void (*insert_after) (iterator_t *this, void *item);
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/**
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* Replace the current item at current iterator position.
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*
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* The iterator position is not changed after replacing.
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*
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* @param this calling iterator
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* @param old old value will be written here(can be NULL)
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* @param new new value
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* @return SUCCESS, FAILED if iterator is on an invalid position
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*/
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status_t (*replace) (iterator_t *this, void **old, void *new);
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/**
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* Removes an element from list at the given iterator position.
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*
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* The iterator is set the the following position:
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* - to the item before, if available
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* - it gets reseted, otherwise
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*
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* @return SUCCESS, FAILED if iterator is on an invalid position
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*/
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status_t (*remove) (iterator_t *this);
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/**
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* Resets the iterator position.
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*
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* After reset, the iterator_t objects doesn't point to an element.
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* A call to iterator_t.has_next is necessary to do any other operations
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* with the resetted iterator.
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*/
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void (*reset) (iterator_t *this);
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/**
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* Destroys an iterator.
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*/
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void (*destroy) (iterator_t *this);
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};
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#endif /*ITERATOR_H_ @} */
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