src/cx/linked_list.h

Mon, 20 Dec 2021 13:01:38 +0100

author
Mike Becker <universe@uap-core.de>
date
Mon, 20 Dec 2021 13:01:38 +0100
changeset 480
e3be53a3354f
parent 478
599770bb6314
child 481
eef025d82a34
permissions
-rw-r--r--

add cx_linked_list_find()

     1 /*
     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
     3  *
     4  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
     5  *
     6  * Redistribution and use in source and binary forms, with or without
     7  * modification, are permitted provided that the following conditions are met:
     8  *
     9  *   1. Redistributions of source code must retain the above copyright
    10  *      notice, this list of conditions and the following disclaimer.
    11  *
    12  *   2. Redistributions in binary form must reproduce the above copyright
    13  *      notice, this list of conditions and the following disclaimer in the
    14  *      documentation and/or other materials provided with the distribution.
    15  *
    16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    19  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
    20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    26  * POSSIBILITY OF SUCH DAMAGE.
    27  */
    28 /**
    29  * \file linked_list.h
    30  * \brief Linked list implementation.
    31  * \details Also provides several low-level functions for custom linked list implementations.
    32  * \author Mike Becker
    33  * \author Olaf Wintermann
    34  * \version 3.0
    35  * \copyright 2-Clause BSD License
    36  */
    38 #ifndef UCX_LINKED_LIST_H
    39 #define UCX_LINKED_LIST_H
    41 #include <stddef.h>
    42 #include "list.h"
    44 #ifdef __cplusplus
    45 extern "C" {
    46 #endif
    48 /**
    49  * Allocates a linked list for storing elements with \p item_size bytes each.
    50  *
    51  * Elements added to the list are copied.
    52  *
    53  * @param allocator the allocator for allocating the list nodes
    54  * @param comparator the comparator for the elements
    55  * @param item_size the size of each element in bytes
    56  * @return the created list
    57  */
    58 CxList cxLinkedListCreate(CxAllocator allocator, CxListComparator comparator, size_t item_size);
    60 /**
    61  * Allocates a linked list for storing pointers.
    62  *
    63  * If you want to store the elements directly in this list, use cxLinkedListCreate().
    64  *
    65  * @param allocator the allocator for allocating the list nodes
    66  * @param comparator the comparator for the elements
    67  * @return the created list
    68  */
    69 CxList cxPointerLinkedListCreate(CxAllocator allocator, CxListComparator comparator);
    71 /**
    72  * Deallocates the memory of the entire list.
    73  *
    74  * \attention If this is a pointer list, the memory the pointers are referring to is \em not freed.
    75  *
    76  * @param list the list
    77  */
    78 void cxLinkedListDestroy(CxList list);
    80 /**
    81  * Finds the node at a certain index.
    82  *
    83  * This function can be used to start at an arbitrary position within the list.
    84  * If the search index is large than the start index, \p loc_advance must denote
    85  * the location of some sort of \c next pointer (i.e. a pointer to the next node).
    86  * But it is also possible that the search index is smaller than the start index
    87  * (e.g. in cases where traversing a list backwards is faster) in which case
    88  * \p loc_advance must denote the location of some sort of \c prev pointer
    89  * (i.e. a pointer to the previous node).
    90  *
    91  * @param start a pointer to the start node
    92  * @param start_index the start index
    93  * @param loc_advance the location of the pointer to advance
    94  * @param index the search index
    95  * @return the node found at the specified index
    96  */
    97 void *cx_linked_list_at(void *start, size_t start_index, ptrdiff_t loc_advance, size_t index)
    98 __attribute__((__nonnull__));
   100 /**
   101  * Finds the index of an element within a linked list.
   102  *
   103  * @param start a pointer to the start node
   104  * @param loc_advance the location of the pointer to advance
   105  * @param loc_data the location of the \c data pointer within your node struct
   106  * @param follow_ptr \c false if the pointer denoted by \p loc_data shall be passed to the \p cmp_func.
   107  * If \c true, the data at \p loc_data is assumed to be a pointer, dereferenced, and then passed to \p cmp_func.
   108  * @param cmp_func a compare function to compare \p elem against the node data
   109  * @param elem a pointer to the element to find
   110  * @return the index of the element or a past-one index if the element could not be found
   111  */
   112 size_t cx_linked_list_find(void *start, ptrdiff_t loc_advance, ptrdiff_t loc_data, int follow_ptr,
   113                            CxListComparator cmp_func, void *elem)
   114 __attribute__((__nonnull__));
   116 /**
   117  * Finds the first node in a linked list.
   118  *
   119  * The function starts with the pointer denoted by \p node and traverses the list
   120  * along a prev pointer whose location within the node struct is
   121  * denoted by \p loc_prev.
   122  *
   123  * @param node a pointer to a node in the list
   124  * @param loc_prev the location of the \c prev pointer
   125  */
   126 void *cx_linked_list_first(void *node, ptrdiff_t loc_prev)
   127 __attribute__((__nonnull__));
   129 /**
   130  * Finds the last node in a linked list.
   131  *
   132  * The function starts with the pointer denoted by \p node and traverses the list
   133  * along a next pointer whose location within the node struct is
   134  * denoted by \p loc_next.
   135  *
   136  * @param node a pointer to a node in the list
   137  * @param loc_next the location of the \c next pointer
   138  * @return a pointer to the last node
   139  */
   140 void *cx_linked_list_last(void *node, ptrdiff_t loc_next)
   141 __attribute__((__nonnull__));
   143 /**
   144  * Finds the predecessor of a node in case it is not linked.
   145  *
   146  * \remark If \p node is not contained in the list starting with \p begin, the behavior is undefined.
   147  *
   148  * @param begin the node where to start the search
   149  * @param loc_next the location of the \c next pointer
   150  * @param node the successor of the node to find
   151  * @return the node or \c NULL if \p node has no predecessor
   152  */
   153 void *cx_linked_list_prev(void *begin, ptrdiff_t loc_next, void *node)
   154 __attribute__((__nonnull__));
   156 /**
   157  * Adds a new node to a linked list.
   158  * The node must not be part of any list already.
   159  *
   160  * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
   161  *
   162  * @param begin a pointer to the begin node pointer (if your list has one)
   163  * @param end a pointer to the end node pointer (if your list has one)
   164  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
   165  * @param loc_next the location of a \c next pointer within your node struct (required)
   166  * @param new_node a pointer to the node that shall be appended
   167  */
   168 void cx_linked_list_add(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node)
   169 __attribute__((__nonnull__(5)));
   171 /**
   172  * Prepends a new node to a linked list.
   173  * The node must not be part of any list already.
   174  *
   175  * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
   176  *
   177  * @param begin a pointer to the begin node pointer (if your list has one)
   178  * @param end a pointer to the end node pointer (if your list has one)
   179  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
   180  * @param loc_next the location of a \c next pointer within your node struct (required)
   181  * @param new_node a pointer to the node that shall be prepended
   182  */
   183 void cx_linked_list_prepend(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node)
   184 __attribute__((__nonnull__(5)));
   186 /**
   187  * Removes a node from the linked list.
   188  *
   189  * If the node to remove is the begin (resp. end) node of the list and if \p begin (resp. \p end)
   190  * addresses are provided, the pointers are adjusted accordingly.
   191  *
   192  * The following combinations of arguments are valid (more arguments are optional):
   193  * \li \p loc_next and \p loc_prev (ancestor node is determined by using the prev pointer, overall O(1) performance)
   194  * \li \p loc_next and \p begin (ancestor node is determined by list traversal, overall O(n) performance)
   195  *
   196  * \remark The \c next and \c prev pointers of the removed node are not cleared by this function and may still be used
   197  * to traverse to a former adjacent node in the list.
   198  *
   199  * @param begin a pointer to the begin node pointer (optional)
   200  * @param end a pointer to the end node pointer (optional)
   201  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
   202  * @param loc_next the location of a \c next pointer within your node struct (required)
   203  * @param node the node to remove
   204  */
   205 void cx_linked_list_remove(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *node)
   206 __attribute__((__nonnull__(5)));
   209 /**
   210  * Determines the size of a linked list starting with \p node.
   211  * @param node the first node
   212  * @param loc_next the location of the \c next pointer within the node struct
   213  * @return the size of the list or zero if \p node is \c NULL
   214  */
   215 size_t cx_linked_list_size(void *node, ptrdiff_t loc_next);
   217 /**
   218  * Sorts a linked list based on a comparison function.
   219  *
   220  * This function can work with linked lists of the following structures:
   221  * \code
   222  * typedef struct node node;
   223  * struct node {
   224  *   node* prev;
   225  *   node* next;
   226  *   my_payload data; // in this case set follow_ptr = 0
   227  * }
   228  *
   229  * typedef struct ptr_node ptr_node;
   230  * struct ptr_node {
   231  *   ptr_node* prev;
   232  *   ptr_node* next;
   233  *   my_payload* data; // in this case set follow_ptr = 1
   234  * }
   235  * \endcode
   236  *
   237  * @note This is a recursive function with at most logarithmic recursion depth.
   238  *
   239  * @param begin a pointer to the begin node pointer (required)
   240  * @param end a pointer to the end node pointer (optional)
   241  * @param loc_prev the location of a \c prev pointer within your node struct (negative if not present)
   242  * @param loc_next the location of a \c next pointer within your node struct (required)
   243  * @param loc_data the location of the \c data pointer within your node struct
   244  * @param follow_ptr \c false if the pointer denoted by \p loc_data shall be passed to the \p cmp_func.
   245  * If \c true, the data at \p loc_data is assumed to be a pointer, dereferenced, and then passed to \p cmp_func.
   246  * @param cmp_func the compare function defining the sort order
   247  */
   248 void cx_linked_list_sort(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next,
   249                          ptrdiff_t loc_data, int follow_ptr, CxListComparator cmp_func)
   250 __attribute__((__nonnull__(1, 7)));
   253 /**
   254  * Reverses the order of the nodes in a linked list.
   255  *
   256  * @param begin a pointer to the begin node pointer (required)
   257  * @param end a pointer to the end node pointer (optional)
   258  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
   259  * @param loc_next the location of a \c next pointer within your node struct (required)
   260  */
   261 void cx_linked_list_reverse(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next)
   262 __attribute__((__nonnull__(1)));
   264 #ifdef __cplusplus
   265 } /* extern "C" */
   266 #endif
   268 #endif /* UCX_LINKED_LIST_H */

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