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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2017 Mike Becker, Olaf Wintermann 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
 */
/**
 * Doubly linked list implementation.
 * 
 * @file   list.h
 * @author Mike Becker
 * @author Olaf Wintermann
 */

#ifndef UCX_LIST_H
#define	UCX_LIST_H

#include "ucx.h"
#include "allocator.h"

#ifdef	__cplusplus
extern "C" {
#endif

/**
 * Loop statement for UCX lists.
 * 
 * The first argument is the name of the iteration variable. The scope of
 * this variable is limited to the <code>UCX_FOREACH</code> statement.
 * 
 * The second argument is a pointer to the list. In most cases this will be the
 * pointer to the first element of the list, but it may also be an arbitrary
 * element of the list. The iteration will then start with that element.
 * 
 * @param list The first element of the list
 * @param elem The variable name of the element
 */
#define UCX_FOREACH(elem,list) \
        for (UcxList* elem = list ; elem != NULL ; elem = elem->next)

/**
 * UCX list type.
 * @see UcxList
 */
typedef struct UcxList UcxList;

/**
 * UCX list structure.
 */
struct UcxList {
    /**
     * List element payload.
     */
    void    *data;
    /**
     * Pointer to the next list element or <code>NULL</code>, if this is the
     * last element.
     */
    UcxList *next;
    /**
     * Pointer to the previous list element or <code>NULL</code>, if this is
     * the first element.
     */
    UcxList *prev;
};

/**
 * Creates an element-wise copy of a list.
 * 
 * This function clones the specified list by creating new list elements and
 * copying the data with the specified copy_func(). If no copy_func() is
 * specified, a shallow copy is created and the new list will reference the
 * same data as the source list.
 * 
 * @param list the list to copy
 * @param cpyfnc a pointer to the function that shall copy an element (may be
 * <code>NULL</code>)
 * @param data additional data for the copy_func()
 * @return a pointer to the copy
 */
UcxList *ucx_list_clone(UcxList *list, copy_func cpyfnc, void* data);

/**
 * Creates an element-wise copy of a list using a UcxAllocator.
 * 
 * See ucx_list_clone() for details.
 * 
 * You might want to pass the allocator via the <code>data</code> parameter,
 * to access it within the copy function for making deep copies.
 * 
 * @param allocator the allocator to use
 * @param list the list to copy
 * @param cpyfnc a pointer to the function that shall copy an element (may be
 * <code>NULL</code>)
 * @param data additional data for the copy_func()
 * @return a pointer to the copy
 * @see ucx_list_clone()
 */
UcxList *ucx_list_clone_a(UcxAllocator *allocator, UcxList *list,
        copy_func cpyfnc, void* data);

/**
 * Compares two UCX lists element-wise by using a compare function.
 * 
 * Each element of the two specified lists are compared by using the specified
 * compare function and the additional data. The type and content of this
 * additional data depends on the cmp_func() used.
 * 
 * If the list pointers denote elements within a list, the lists are compared
 * starting with the denoted elements. Thus any previous elements are not taken
 * into account. This might be useful to check, if certain list tails match
 * each other.
 * 
 * @param list1 the first list
 * @param list2 the second list
 * @param cmpfnc the compare function
 * @param data additional data for the compare function
 * @return 1, if and only if the two lists equal element-wise, 0 otherwise
 */
int ucx_list_equals(const UcxList *list1, const UcxList *list2,
        cmp_func cmpfnc, void* data);

/**
 * Destroys the entire list.
 * 
 * The members of the list are not automatically freed, so ensure they are
 * otherwise referenced or destroyed by ucx_list_free_contents().
 * Otherwise, a memory leak is likely to occur.
 * 
 * <b>Caution:</b> the argument <b>MUST</b> denote an entire list (i.e. a call
 * to ucx_list_first() on the argument must return the argument itself)
 * 
 * @param list the list to free
 * @see ucx_list_free_contents()
 */
void ucx_list_free(UcxList *list);

/**
 * Destroys the entire list using a UcxAllocator.
 * 
 * See ucx_list_free() for details.
 * 
 * @param allocator the allocator to use
 * @param list the list to free
 * @see ucx_list_free()
 */
void ucx_list_free_a(UcxAllocator *allocator, UcxList *list);

/**
 * Destroys the contents of the specified list by calling the specified
 * destructor on each of them.
 * 
 * Note, that the contents are not usable afterwards and the list should be
 * destroyed with ucx_list_free().
 *
 * If no destructor is specified (<code>NULL</code>), stdlib's free() is used.
 * 
 * @param list the list for which the contents shall be freed
 * @param destr optional destructor function
 * @see ucx_list_free()
 */
void ucx_list_free_content(UcxList* list, ucx_destructor destr);


/**
 * Inserts an element at the end of the list.
 * 
 * This is generally an O(n) operation, as the end of the list is retrieved with
 * ucx_list_last().
 * 
 * @param list the list where to append the data, or <code>NULL</code> to
 * create a new list
 * @param data the data to insert
 * @return <code>list</code>, if it is not <code>NULL</code> or a pointer to
 * the newly created list otherwise
 */
UcxList *ucx_list_append(UcxList *list, void *data);

/**
 * Inserts an element at the end of the list using a UcxAllocator.
 * 
 * See ucx_list_append() for details.
 * 
 * @param allocator the allocator to use
 * @param list the list where to append the data, or <code>NULL</code> to
 * create a new list
 * @param data the data to insert
 * @return <code>list</code>, if it is not <code>NULL</code> or a pointer to
 * the newly created list otherwise
 * @see ucx_list_append()
 */
UcxList *ucx_list_append_a(UcxAllocator *allocator, UcxList *list, void *data);


/**
 * Inserts an element at the beginning of the list.
 * 
 * You <i>should</i> overwrite the old list pointer by calling
 * <code>mylist = ucx_list_prepend(mylist, mydata);</code>. However, you may
 * also perform successive calls of ucx_list_prepend() on the same list pointer,
 * as this function always searchs for the head of the list with
 * ucx_list_first().
 * 
 * @param list the list where to insert the data or <code>NULL</code> to create
 * a new list
 * @param data the data to insert
 * @return a pointer to the new list head
 */
UcxList *ucx_list_prepend(UcxList *list, void *data);

/**
 * Inserts an element at the beginning of the list using a UcxAllocator.
 * 
 * See ucx_list_prepend() for details.
 * 
 * @param allocator the allocator to use
 * @param list the list where to insert the data or <code>NULL</code> to create
 * a new list
 * @param data the data to insert
 * @return a pointer to the new list head
 * @see ucx_list_prepend()
 */
UcxList *ucx_list_prepend_a(UcxAllocator *allocator, UcxList *list, void *data);

/**
 * Concatenates two lists.
 * 
 * Either of the two arguments may be <code>NULL</code>.
 * 
 * This function modifies the references to the next/previous element of
 * the last/first element of <code>list1</code>/<code>
 * list2</code>.
 * 
 * @param list1 first list
 * @param list2 second list
 * @return if <code>list1</code> is <code>NULL</code>, <code>list2</code> is
 * returned, otherwise <code>list1</code> is returned
 */
UcxList *ucx_list_concat(UcxList *list1, UcxList *list2);

/**
 * Returns the first element of a list.
 * 
 * If the argument is the list pointer, it is directly returned. Otherwise
 * this function traverses to the first element of the list and returns the
 * list pointer.
 * 
 * @param elem one element of the list
 * @return the first element of the list, the specified element is a member of
 */
UcxList *ucx_list_first(const UcxList *elem);

/**
 * Returns the last element of a list.
 * 
 * If the argument has no successor, it is the last element and therefore
 * directly returned. Otherwise this function traverses to the last element of
 * the list and returns it.
 * 
 * @param elem one element of the list
 * @return the last element of the list, the specified element is a member of
 */
UcxList *ucx_list_last(const UcxList *elem);

/**
 * Returns the list element at the specified index.
 * 
 * @param list the list to retrieve the element from
 * @param index index of the element to return
 * @return the element at the specified index or <code>NULL</code>, if the
 * index is greater than the list size
 */
UcxList *ucx_list_get(const UcxList *list, size_t index);

/**
 * Returns the index of an element.
 * 
 * @param list the list where to search for the element
 * @param elem the element to find
 * @return the index of the element or -1 if the list does not contain the
 * element
 */
ssize_t ucx_list_indexof(const UcxList *list, const UcxList *elem);

/**
 * Returns the element count of the list.
 * 
 * @param list the list whose elements are counted
 * @return the element count
 */
size_t ucx_list_size(const UcxList *list);

/**
 * Returns the index of an element containing the specified data.
 *
 * This function uses a cmp_func() to compare the data of each list element
 * with the specified data. If no cmp_func is provided, the pointers are
 * compared.
 * 
 * If the list contains the data more than once, the index of the first
 * occurrence is returned.
 *  
 * @param list the list where to search for the data
 * @param elem the element data
 * @param cmpfnc the compare function
 * @param data additional data for the compare function
 * @return the index of the element containing the specified data or -1 if the
 * data is not found in this list
 */
ssize_t ucx_list_find(UcxList *list, void *elem, cmp_func cmpfnc, void *data);

/**
 * Checks, if a list contains a specific element.
 * 
 * An element is found, if ucx_list_find() returns a value greater than -1.
 * 
 * @param list the list where to search for the data
 * @param elem the element data
 * @param cmpfnc the compare function
 * @param data additional data for the compare function
 * @return 1, if and only if the list contains the specified element data
 * @see ucx_list_find()
 */
int ucx_list_contains(UcxList *list, void *elem, cmp_func cmpfnc, void *data);

/**
 * Sorts a UcxList with natural merge sort.
 * 
 * This function uses O(n) additional temporary memory for merge operations
 * that is automatically freed after each merge.
 * 
 * As the head of the list might change, you <b>MUST</b> call this function
 * as follows: <code>mylist = ucx_list_sort(mylist, mycmpfnc, mydata);</code>.
 * 
 * @param list the list to sort
 * @param cmpfnc the function that shall be used to compare the element data
 * @param data additional data for the cmp_func()
 * @return the sorted list
 */
UcxList *ucx_list_sort(UcxList *list, cmp_func cmpfnc, void *data);

/**
 * Removes an element from the list.
 * 
 * If the first element is removed, the list pointer changes. So it is
 * <i>highly recommended</i> to <i>always</i> update the pointer by calling
 * <code>mylist = ucx_list_remove(mylist, myelem);</code>.
 * 
 * @param list the list from which the element shall be removed
 * @param element the element to remove
 * @return returns the updated list pointer or <code>NULL</code>, if the list
 * is now empty
 */
UcxList *ucx_list_remove(UcxList *list, UcxList *element);

/**
 * Removes an element from the list using a UcxAllocator.
 * 
 * See ucx_list_remove() for details.
 * 
 * @param allocator the allocator to use
 * @param list the list from which the element shall be removed
 * @param element the element to remove
 * @return returns the updated list pointer or <code>NULL</code>, if the list
 * @see ucx_list_remove()
 */
UcxList *ucx_list_remove_a(UcxAllocator *allocator, UcxList *list,
        UcxList *element);

#ifdef	__cplusplus
}
#endif

#endif	/* UCX_LIST_H */