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
/*-------------------------------------------------------------------------
*
* oset.c--
* Fixed format ordered set definitions.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/mmgr/Attic/oset.c,v 1.3 1997/08/24 23:07:50 momjian Exp $
*
* NOTE
* XXX This is a preliminary implementation which lacks fail-fast
* XXX validity checking of arguments.
*
*-------------------------------------------------------------------------
*/
#include "c.h"
#include "utils/memutils.h" /* where declarations of this file goes */
static Pointer OrderedElemGetBase(OrderedElem elem);
static void OrderedElemPush(OrderedElem elem);
static void OrderedElemPushHead(OrderedElem elem);
/*
* OrderedElemGetBase --
* Returns base of enclosing structure.
*/
static Pointer
OrderedElemGetBase(OrderedElem elem)
{
if (elem == (OrderedElem) NULL)
return (Pointer) NULL;
return ((Pointer)((char*)(elem) - (elem)->set->offset));
}
/*
* OrderedSetInit --
*/
void
OrderedSetInit(OrderedSet set, Offset offset)
{
set->head = (OrderedElem)&set->dummy;
set->dummy = NULL;
set->tail = (OrderedElem)&set->head;
set->offset = offset;
}
/*
* OrderedSetContains --
* True iff ordered set contains given element.
*/
bool
OrderedSetContains(OrderedSet set, OrderedElem elem)
{
return ((bool)(elem->set == set && (elem->next || elem->prev)));
}
/*
* OrderedSetGetHead --
*/
Pointer
OrderedSetGetHead(OrderedSet set)
{
register OrderedElem elem;
elem = set->head;
if (elem->next) {
return (OrderedElemGetBase(elem));
}
return (NULL);
}
/*
* OrderedSetGetTail --
*/
#ifdef NOT_USED
Pointer
OrderedSetGetTail(OrderedSet set)
{
register OrderedElem elem;
elem = set->tail;
if (elem->prev) {
return (OrderedElemGetBase(elem));
}
return (NULL);
}
#endif
/*
* OrderedElemGetPredecessor --
*/
Pointer
OrderedElemGetPredecessor(OrderedElem elem)
{
elem = elem->prev;
if (elem->prev) {
return (OrderedElemGetBase(elem));
}
return (NULL);
}
/*
* OrderedElemGetSuccessor --
*/
Pointer
OrderedElemGetSuccessor(OrderedElem elem)
{
elem = elem->next;
if (elem->next) {
return (OrderedElemGetBase(elem));
}
return (NULL);
}
/*
* OrderedElemPop --
*/
void
OrderedElemPop(OrderedElem elem)
{
elem->next->prev = elem->prev;
elem->prev->next = elem->next;
/* assignments used only for error detection */
elem->next = NULL;
elem->prev = NULL;
}
/*
* OrderedElemPushInto --
*/
void
OrderedElemPushInto(OrderedElem elem, OrderedSet set)
{
elem->set = set;
/* mark as unattached */
elem->next = NULL;
elem->prev = NULL;
OrderedElemPush(elem);
}
/*
* OrderedElemPush --
*/
static void
OrderedElemPush(OrderedElem elem)
{
OrderedElemPushHead(elem);
}
/*
* OrderedElemPushHead --
*/
static void
OrderedElemPushHead(OrderedElem elem)
{
elem->next = elem->set->head;
elem->prev = (OrderedElem)&elem->set->head;
elem->next->prev = elem;
elem->prev->next = elem;
}