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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2021 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.
 */
/**
 * \file list.h
 * \brief Interface for list implementations.
 * \author Mike Becker
 * \author Olaf Wintermann
 * \version 3.0
 * \copyright 2-Clause BSD License
 */

#ifndef UCX_LIST_H
#define UCX_LIST_H

#include "common.h"
#include "allocator.h"
#include "iterator.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * A comparator function comparing two list elements.
 */
typedef int(*CxListComparator)(
        void const *left,
        void const *right
);

/**
 * List class type.
 */
typedef struct cx_list_class_s cx_list_class;

/**
 * Structure for holding the base data of a list.
 */
struct cx_list_s {
    /**
     * The list class definition.
     */
    cx_list_class *cl;
    /**
     * The allocator to use.
     */
    CxAllocator *allocator;
    /**
     * A mandatory destructor for the list structure.
     */
    cx_destructor_func list_destructor;
    /**
     * An optional destructor for the list contents.
     */
    cx_destructor_func content_destructor;
    /**
     * The comparator function for the elements.
     */
    CxListComparator cmpfunc;
    /**
     * The size of each element (payload only).
     */
    size_t itemsize;
    /**
     * The size of the list (number of currently stored elements).
     */
    size_t size;
    /**
     * The capacity of the list (maximum number of elements).
     */
    size_t capacity;
    /**
     * Flag indicating whether cxListDestroy() shall free the list structure,
     * even if cx_list_s.list_destructor did not do that.
     */
    bool autofree;
    /**
     * Flag indicating whether cxListDestroy() shall free each list element,
     * even if cx_list_s.content_destructor did not do that.
     */
    bool autofree_contents;
};

/**
 * The class definition for arbitrary lists.
 */
struct cx_list_class_s {
    /**
     * Member function for adding an element.
     */
    int (*add)(
            struct cx_list_s *list,
            void const *elem
    );

    /**
     * Member function for inserting an element.
     */
    int (*insert)(
            struct cx_list_s *list,
            size_t index,
            void const *elem
    );

    /**
     * Member function for inserting an element relative to an iterator position.
     */
    int (*insert_iter)(
            struct cx_iterator_s *iter,
            void const *elem,
            int prepend
    );

    /**
     * Member function for removing an element.
     */
    int (*remove)(
            struct cx_list_s *list,
            size_t index
    );

    /**
     * Member function for element lookup.
     */
    void *(*at)(
            struct cx_list_s const *list,
            size_t index
    );

    /**
     * Member function for finding an element.
     */
    size_t (*find)(
            struct cx_list_s const *list,
            void const *elem
    );

    /**
     * Member function for sorting the list in place.
     */
    void (*sort)(struct cx_list_s *list);

    /**
     * Member function for comparing this list to another list of the same type.
     */
    int (*compare)(
            struct cx_list_s const *list,
            struct cx_list_s const *other
    );

    /**
     * Member function for reversing the order of the items.
     */
    void (*reverse)(struct cx_list_s *list);

    /**
     * Returns an iterator pointing to the specified index.
     */
    struct cx_iterator_s (*iterator)(
            struct cx_list_s *list,
            size_t index
    );
};

/**
 * Common type for all list implementations.
 */
typedef struct cx_list_s CxList;

/**
 * Convenience function to configure the memory management for this list.
 *
 * @param list the list to configure
 * @param list_destructor an alternative list destructor to use (if \c NULL, the current destructor remains unchanged)
 * @param content_destructor the content destructor to use (if \c NULL, no content destructor is used)
 * @param list_autofree a flag indicating, if the list allocator shall free the list, if the destructor did not do that
 * @param content_autofree a flag indicating, if the list allocator shall free an element,
 * if the content destructor did not do that or no content destructor exists
 */
static inline void cxListMemoryMgmt(
        CxList *list,
        cx_destructor_func list_destructor,
        cx_destructor_func content_destructor,
        bool list_autofree,
        bool content_autofree
) {
    if (list_destructor != NULL) list->list_destructor = list_destructor;
    list->content_destructor = content_destructor;
    list->autofree = list_autofree;
    list->autofree_contents = content_autofree;
}

/**
 * Adds an item to the end of the list.
 *
 * @param list the list
 * @param elem a pointer to the element to add
 * @return zero on success, non-zero on memory allocation failure
 */
static inline int cxListAdd(
        CxList *list,
        void const *elem
) {
    return list->cl->add(list, elem);
}

/**
 * Inserts an item at the specified index.
 *
 * If \p index equals the list \c size, this is effectively cxListAdd().
 *
 * @param list the list
 * @param index the index the element shall have
 * @param elem a pointer to the element to add
 * @return zero on success, non-zero on memory allocation failure
 * or when the index is out of bounds
 * @see cxListInsertAfter()
 * @see cxListInsertBefore()
 */
static inline int cxListInsert(
        CxList *list,
        size_t index,
        void const *elem
) {
    return list->cl->insert(list, index, elem);
}

/**
 * Inserts an element after the current location of the specified iterator.
 *
 * The used iterator remains operational, but all other active iterators should
 * be considered invalidated.
 *
 * If \p iter is not a list iterator, the behavior is undefined.
 * If \p iter is a past-the-end iterator, the new element gets appended to the list.
 *
 * @param iter an iterator
 * @param elem the element to insert
 * @return zero on success, non-zero on memory allocation failure
 * @see cxListInsert()
 * @see cxListInsertBefore()
 */
static inline int cxListInsertAfter(
        CxIterator *iter,
        void const *elem
) {
    return ((struct cx_list_s *) iter->src_handle)->cl->insert_iter(iter, elem, 0);
}

/**
 * Inserts an element before the current location of the specified iterator.
 *
 * The used iterator remains operational, but all other active iterators should
 * be considered invalidated.
 *
 * If \p iter is not a list iterator, the behavior is undefined.
 * If \p iter is a past-the-end iterator, the new element gets appended to the list.
 *
 * @param iter an iterator
 * @param elem the element to insert
 * @return zero on success, non-zero on memory allocation failure
 * @see cxListInsert()
 * @see cxListInsertAfter()
 */
static inline int cxListInsertBefore(
        CxIterator *iter,
        void const *elem
) {
    return ((struct cx_list_s *) iter->src_handle)->cl->insert_iter(iter, elem, 1);
}

/**
 * Removes the element at the specified index.
 * @param list the list
 * @param index the index of the element
 * @return zero on success, non-zero if the index is out of bounds
 */
static inline int cxListRemove(
        CxList *list,
        size_t index
) {
    return list->cl->remove(list, index);
}

/**
 * Returns a pointer to the element at the specified index.
 *
 * @param list the list
 * @param index the index of the element
 * @return a pointer to the element or \c NULL if the index is out of bounds
 */
static inline void *cxListAt(
        CxList *list,
        size_t index
) {
    return list->cl->at(list, index);
}

/**
 * Returns an iterator pointing to the item at the specified index.
 *
 * The returned iterator is position-aware.
 *
 * If the index is out of range, a past-the-end iterator will be returned.
 *
 * @param list the list
 * @param index the index where the iterator shall point at
 * @return a new iterator
 */
static inline CxIterator cxListIterator(
        CxList *list,
        size_t index
) {
    return list->cl->iterator(list, index);
}

/**
 * Returns an iterator pointing to the first item of the list.
 *
 * The returned iterator is position-aware.
 *
 * If the list is empty, a past-the-end iterator will be returned.
 *
 * @param list the list
 * @return a new iterator
 */
static inline CxIterator cxListBegin(CxList *list) {
    return list->cl->iterator(list, 0);
}

/**
 * Returns the index of the first element that equals \p elem.
 *
 * Determining equality is performed by the list's comparator function.
 *
 * @param list the list
 * @param elem the element to find
 * @return the index of the element or \c (size+1) if the element is not found
 */
static inline size_t cxListFind(
        CxList *list,
        void const *elem
) {
    return list->cl->find(list, elem);
}

/**
 * Sorts the list in place.
 *
 * \remark The underlying sort algorithm is implementation defined.
 *
 * @param list the list
 */
static inline void cxListSort(CxList *list) {
    list->cl->sort(list);
}

/**
 * Reverses the order of the items.
 *
 * @param list the list
 */
static inline void cxListReverse(CxList *list) {
    list->cl->reverse(list);
}

/**
 * Compares a list to another list of the same type.
 *
 * First, the list sizes are compared. If they match, the lists are compared element-wise.
 *
 * @param list the list
 * @param other the list to compare to
 * @return zero, if both lists are equal element wise, negative if the first list is smaller, zero if the first list is larger
 */
static inline int cxListCompare(
        CxList *list,
        CxList *other
) {
    return list->cl->compare(list, other);
}

/**
 * Calls the list's destructor function for every element.
 * If CxList.autofree_content is \c true, the elements are automatically free'd
 * unless the content destructor function did not already do that.
 * Similarly, if CxList.autofree is \c true, the list structure is free'd, unless
 * the list destructor function did not already do that.
 *
 * This function itself is a destructor function for the CxList.
 *
 * @param list the list which contents shall be destroyed
 * @return \p list if the list structure has been free'd during the process
 */
__attribute__((__nonnull__))
CxList *cxListDestroy(CxList *list);

#ifdef __cplusplus
} /* extern "C" */
#endif

#endif /* UCX_LIST_H */