Sun, 07 Feb 2021 21:03:30 +0100
use named fields to access node memory
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 */
29 #include "cx/linked_list.h"
30 #include <stdint.h>
31 #include <string.h>
33 /* LOW LEVEL LINKED LIST FUNCTIONS */
35 #define CX_LL_PTR(cur, off) ((void**)(((char*)cur)+off))
37 void *cx_linked_list_last(void **begin, void **end, ptrdiff_t loc_next) {
38 if (end != NULL) {
39 return *end;
40 } else {
41 if (begin == NULL || *begin == NULL)
42 return NULL;
44 void *cur = *begin;
45 void *last;
46 do {
47 last = cur;
48 } while ((cur = *CX_LL_PTR(cur, loc_next)) != NULL);
50 return last;
51 }
52 }
54 int cx_linked_list_add(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *newnode) {
55 // TODO: how do we report error messages?
56 if (loc_next < 0 || (begin == NULL && end == NULL)) {
57 return 1;
58 }
60 void *last = cx_linked_list_last(begin, end, loc_next);
61 if (last == NULL) {
62 if (begin == NULL) {
63 return 1;
64 } else {
65 *begin = newnode;
66 return 0;
67 }
68 }
70 void **next = CX_LL_PTR(last, loc_next);
71 *next = newnode;
72 if (loc_prev >= 0) {
73 void **prev = CX_LL_PTR(newnode, loc_prev);
74 *prev = last;
75 }
77 return 0;
78 }
80 /* HIGH LEVEL LINKED LIST IMPLEMENTATION */
82 struct cx_linked_list_node {
83 void *prev;
84 void *next;
85 int payload;
86 };
88 typedef struct {
89 void *begin;
90 void *end;
91 } cx_linked_list;
93 int cx_ll_add(cx_list *list, void *elem) {
94 cx_linked_list *listdata = list->listdata;
95 CxAllocator allocator = list->allocator;
97 struct cx_linked_list_node *node = cxMalloc(allocator,
98 sizeof(struct cx_linked_list_node) - sizeof(int) + list->itemsize);
99 if (node == NULL)
100 return 1;
102 node->next = NULL;
103 memcpy(&node->payload, elem, list->itemsize);
105 int ret = cx_linked_list_add(
106 &listdata->begin,
107 &listdata->end,
108 offsetof(struct cx_linked_list_node, prev),
109 offsetof(struct cx_linked_list_node, next),
110 node
111 );
112 if (ret == 0) {
113 list->size++;
114 return 0;
115 } else {
116 return ret;
117 }
118 }
120 int cx_ll_insert(cx_list *list, size_t index, void *elem) {
121 cx_linked_list *listdata = list->listdata;
122 // TODO: implement using low level API
123 return 1;
124 }
126 void *cx_ll_remove(cx_list *list, size_t index) {
127 cx_linked_list *listdata = list->listdata;
128 // TODO: implement using low level API
129 return NULL;
130 }
132 size_t cx_ll_find(cx_list *list, void *elem) {
133 cx_linked_list *listdata = list->listdata;
134 // TODO: implement using low level API
135 return 0;
136 }
139 cx_list_class cx_linked_list_class = {
140 cx_ll_add,
141 cx_ll_insert,
142 cx_ll_remove,
143 cx_ll_find
144 };
146 CxList cxLinkedListCreate(CxAllocator allocator, CxListComparator comparator, size_t itemsize) {
147 CxList list = cxMalloc(allocator, sizeof(list));
148 if (list == NULL)
149 return NULL;
151 list->cl = &cx_linked_list_class;
152 list->data.allocator = allocator;
153 list->data.cmpfunc = comparator;
154 list->data.size = 0;
155 list->data.itemsize = itemsize;
156 list->data.capacity = SIZE_MAX;
157 list->data.listdata = cxCalloc(allocator, 1, sizeof(cx_linked_list));
158 if (list->data.listdata == NULL) {
159 cxFree(allocator, list);
160 return NULL;
161 }
162 }