summaryrefslogtreecommitdiff
path: root/lib/tlists.h
blob: e1ed79ea4f8b7080f109db21d8667085dfd6d627 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
/*
 *	BIRD Library -- Typed Linked Lists
 *
 *	(c) 2022 Maria Matejka <mq@jmq.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 *
 *
 *	This implementation of linked lists forces its members to be
 *	typed. On the other hand, it needs to be implemented as ugly macros to
 *	keep the needed genericity.
 *
 *	Usage:
 *	1. Include this file
 *	2. Define the node structure
 *	3. For every list type you need to define:
 *	  A. #define TLIST_PREFIX and other macros
 *	  B. Include this file once again
 *
 *	Macros to define:
 *	TLIST_PREFIX:		prefix to prepend to everything generated
 *	TLIST_TYPE:		the actual node type
 *	TLIST_ITEM:		where the tlist structure is
 *	TLIST_WANT_WALK:	if defined, generates a helper functions for list walking macros
 *	TLIST_WANT_ADD_HEAD:	if defined, TLIST_PREFIX_add_head() is generated to
 *				add an item to the beginning of the list
 *	TLIST_WANT_ADD_TAIL:	if defined, TLIST_PREFIX_add_tail() is generated to
 *				add an item to the end of the list
 *
 *	TLIST_PREFIX_rem_node() is generated always.
 *
 *	All these macros are #undef-ed by including this file.
 *
 *	Example:
 *
 *	#include "lib/tlists.h"
 *	
 *	struct foo {
 *	  ...
 *	  TLIST_NODE(bar, struct foo) baz;
 *	  ...
 *	};
 *
 *	#define TLIST_PREFIX  bar
 *	#define TLIST_TYPE    struct foo
 *	#define TLIST_ITEM    baz
 *
 *	#define TLIST_WANT_WALK
 *	#define TLIST_WANT_ADD_HEAD
 *
 *	#include "lib/tlists.h"
 *
 *	...
 *	(end of example)
 *
 */

#ifdef _BIRD_LIB_TLISTS_H_
# ifdef TLIST_PREFIX

/* Check for mandatory arguments */
#ifndef TLIST_TYPE
#error "TLIST_TYPE must be defined"
#endif
#ifndef TLIST_ITEM
#error "TLIST_ITEM must be defined"
#endif
#ifndef TLIST_PREFIX
#error "TLIST_PREFIX must be defined"
#endif

#define TLIST_NAME(x)	MACRO_CONCAT_AFTER(TLIST_PREFIX,_##x)
#ifndef TLIST_LIST_STRUCT
#define TLIST_LIST_STRUCT	TLIST_NAME(list)
#endif

typedef struct TLIST_LIST_STRUCT {
  TLIST_TYPE *first;
  TLIST_TYPE *last;
} TLIST_LIST_STRUCT;

#ifdef TLIST_WANT_WALK
static inline struct TLIST_NAME(node) * TLIST_NAME(node_get)(TLIST_TYPE *node)
{ return &(node->TLIST_ITEM); }
#endif

#ifdef TLIST_WANT_ADD_HEAD
static inline void TLIST_NAME(add_head)(TLIST_LIST_STRUCT *list, TLIST_TYPE *node)
{
  ASSERT_DIE(!node->TLIST_ITEM.prev && !node->TLIST_ITEM.next);
  if (node->TLIST_ITEM.next = list->first)
    list->first->TLIST_ITEM.prev = node;
  else
    list->last = node;
  list->first = node;
}
#endif

#ifdef TLIST_WANT_ADD_TAIL
static inline void TLIST_NAME(add_tail)(TLIST_LIST_STRUCT *list, TLIST_TYPE *node)
{
  ASSERT_DIE(!node->TLIST_ITEM.prev && !node->TLIST_ITEM.next);
  if (node->TLIST_ITEM.prev = list->last)
    list->last->TLIST_ITEM.next = node;
  else
    list->first = node;
  list->last = node;
}
#endif

static inline void TLIST_NAME(rem_node)(TLIST_LIST_STRUCT *list, TLIST_TYPE *node)
{
  if (node->TLIST_ITEM.prev)
    node->TLIST_ITEM.prev->TLIST_ITEM.next = node->TLIST_ITEM.next;
  else
  {
    ASSERT_DIE(list->first == node);
    list->first = node->TLIST_ITEM.next;
  }

  if (node->TLIST_ITEM.next)
    node->TLIST_ITEM.next->TLIST_ITEM.prev = node->TLIST_ITEM.prev;
  else
  {
    ASSERT_DIE(list->last == node);
    list->last = node->TLIST_ITEM.prev;
  }

  node->TLIST_ITEM.next = node->TLIST_ITEM.prev = NULL;
}

#undef TLIST_PREFIX
#undef TLIST_NAME
#undef TLIST_LIST_STRUCT
#undef TLIST_TYPE
#undef TLIST_ITEM
#undef TLIST_WANT_ADD_HEAD
#undef TLIST_WANT_ADD_TAIL

# endif
#else
#define _BIRD_LIB_TLISTS_H_

#include "lib/macro.h"

#if defined(TLIST_NAME) || defined(TLIST_PREFIX)
#error "You should first include lib/tlists.h without requesting a TLIST"
#endif

#define TLIST_NODE(_name, _type)	struct _name##_node { _type *next; _type *prev; }
#define TLIST_LIST(_name)		struct _name##_list 

/* Use ->first and ->last to access HEAD and TAIL */
#define THEAD(_name, _list)  (_list)->first
#define TTAIL(_name, _list)  (_list)->last

/* Walkaround macros: simple and resilient to node removal */
#define WALK_TLIST(_name, _node, _list) \
  for (typeof((_list)->first) _node = (_list)->first; \
      _node; _node = _name##_node_get((_node))->next)

#define WALK_TLIST_DELSAFE(_name, _node, _list) \
  for (typeof((_list)->first) _node = (_list)->first, \
      _helper = _node ? _name##_node_get((_list)->first)->next : NULL; \
      _node; \
      (_node = _helper) ? (_helper = _name##_node_get(_helper)->next) : 0)

/* Empty check */
#define EMPTY_TLIST(_name, _list) (!(_list)->first)

#endif