-
Notifications
You must be signed in to change notification settings - Fork 0
/
ll.c
238 lines (218 loc) · 7.86 KB
/
ll.c
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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
#include "ll.h"
#include <assert.h>
SingleLink *SingleLink_get(const SingleLink *p, uintmax_t n)
{
assert(p);
if (n) {
uintmax_t cnt;
SingleLink_for_n(p, cnt, n)
if (!p->nxt) /* out-of-bounds error */
return NULL;
} else
SingleLink_for_all(p)
;
return (SingleLink *)p; /* Cast away const */
}
DoubleLink *DoubleLink_get(const DoubleLink *p, uintmax_t n, bool back)
{
assert(p);
if (n) {
uintmax_t cnt;
if (back) {
DoubleLink_for_n_back(p, cnt, n)
if (!p->prv)
return NULL;
} else {
DoubleLink_for_n(p, cnt, n)
if (!p->nxt)
return NULL;
}
} else
if (back)
DoubleLink_for_all_back(p)
;
else
DoubleLink_for_all(p)
;
return (DoubleLink *)p;
}
intmax_t SingleLink_len(const SingleLink *begin, const SingleLink *end)
{
assert(begin);
uintmax_t cnt = 0;
if (end)
SingleLink_until(begin, end) {
if (!begin->nxt)
return -1; /* end not found */
cnt++;
}
else
SingleLink_for_all(begin)
cnt++;
return cnt;
}
intmax_t DoubleLink_len(const DoubleLink *begin, const DoubleLink *end, bool back)
{
assert(begin && end);
uintmax_t cnt = 0;
if (back) {
if (end)
DoubleLink_until_back(begin, end) {
if (!begin->prv)
return -1;
cnt++;
}
else
DoubleLink_for_all_back(begin)
cnt++;
} else
if (end)
DoubleLink_until(begin, end) {
if (!begin->nxt)
return -1;
cnt++;
}
else
DoubleLink_for_all(begin)
cnt++;
return cnt;
}
void SingleLink_insert(SingleLink *dst, SingleLink *begin, SingleLink *end)
{
assert(dst && begin && end && SingleLink_len(begin, end) >= 0);
end->nxt = dst->nxt;
dst->nxt = begin;
}
void DoubleLink_insert(DoubleLink *dst, DoubleLink *begin, DoubleLink *end)
{
assert(dst && begin && end && DoubleLink_len(begin, end, false) >= 0);
end->nxt = dst->nxt;
/* If dst->nxt is NULL, dst is the tail node;
* there are none after it to update.
* Otherwise, update the prv of the node after dst.
*/
if (dst->nxt)
dst->nxt->prv = end;
dst->nxt = begin, begin->prv = dst;
}
void SingleLink_remove(SingleLink *begin, SingleLink *end)
{
assert(begin && end && SingleLink_len(begin, end) >= 0);
begin->nxt = end->nxt;
}
void DoubleLink_remove(DoubleLink *begin, DoubleLink *end)
{
assert(begin && end && DoubleLink_len(begin, end, false) >= 0);
begin->nxt = end->nxt;
if (end->nxt)
end->nxt->prv = begin;
}
void DoubleLink_swap(
DoubleLink *a_begin, DoubleLink *a_end,
DoubleLink *b_begin, DoubleLink *b_end
) {
assert(
a_begin && a_end && b_begin && b_end
&& DoubleLink_len(a_begin, a_end, false) >= 0
&& DoubleLink_len(b_begin, b_end, false) >= 0
);
/* Unless a_begin is the head node in its list, update its prv to b_begin */
if (a_begin->prv)
a_begin->prv->nxt = b_begin;
/* If b_begin immediately follows a_end (ranges are consecutive),
* do NOT update a_end's next node's prv to it, as this would result in
* a cicular (infinite) link.
*/
if (a_end->nxt && a_end->nxt != b_begin)
a_end->nxt->prv = b_end;
if (b_begin->prv && b_begin->prv != a_end)
b_begin->prv->nxt = a_begin;
if (b_end->nxt)
b_end->nxt->prv = a_end;
DoubleLink *tmp = a_begin->prv;
/* If a_begin and b_begin are consecutive
* (range a is a singleton consecutive to b),
* exchanging their prv will cause a circular link.
* Instead, make b_begin the node preceeding a_begin.
*/
if (a_begin != b_begin->prv)
a_begin->prv = b_begin->prv;
else
a_begin->prv = b_begin;
b_begin->prv = tmp;
tmp = a_end->nxt;
a_end->nxt = b_end->nxt;
/* Similarly, only exchange b_end and a_end's nxt if they are not consecutive.
* (This implies range b is a singleton consecutive to a).
*/
if (b_end != tmp)
b_end->nxt = tmp;
else
b_end->nxt = a_end;
}
void SingleLink_swap(
SingleLink *a_begin_prv, SingleLink *a_begin, SingleLink *a_end,
SingleLink *b_begin_prv, SingleLink *b_begin, SingleLink *b_end
) {
assert(
a_begin && a_end && b_begin && b_end
&& a_begin_prv? a_begin_prv->nxt == a_begin : true
&& b_begin_prv? b_begin_prv->nxt == b_begin : true
&& SingleLink_len(a_begin, a_end) >= 0
&& SingleLink_len(b_begin, b_end) >= 0
);
if (a_begin_prv)
a_begin_prv->nxt = b_begin;
if (b_begin_prv && b_begin_prv != a_end)
b_begin_prv->nxt = a_begin;
SingleLink *tmp = a_end->nxt;
a_end->nxt = b_end->nxt;
if (b_end != tmp)
b_end->nxt = tmp;
else
b_end->nxt = a_end;
}
void DoubleLink_reverse(DoubleLink *left, DoubleLink *right)
{
assert(left && right && DoubleLink_len(left, right, false) >= 0);
/* Swap nodes from the left with corresponding nodes from the right,
* until the midpoint is reached.
* Do not test for premature end of list.
* If this causes a NULL derefrence, the segfault/UB is well-deserved.
*/
while (left != right) {
DoubleLink *nxt = left->nxt, *prv = right->prv;
DoubleLink_swap(left, left, right, right);
/* As the loop swaps 2 nodes per iteration, a range of even length
* cannot have a real middle node.
* However, just before the theoretical midpoint, the next node from the left
* will be the current node from the right.
* If so, the reversal is complete after the current swap.
*/
if (nxt == right)
break;
left = nxt, right = prv;
}
}
void SingleLink_reverse(SingleLink *begin_prv, SingleLink *begin, SingleLink *end)
{
assert(
begin && end && begin_prv? begin_prv->nxt == begin : true
&& SingleLink_len(begin, end) >= 0
);
/* The loop assumes a range > 1 node */
if (begin == end)
return;
/* If a node preceeds the range, update its nxt to the end of the range */
if (begin_prv)
begin_prv->nxt = end;
/* For each node in the range, set it's nxt to the node preceeding it */
for (
SingleLink *prv = begin_prv, *cur = begin, *nxt = cur->nxt ;;
prv = cur, cur = nxt, nxt = nxt->nxt
) {
cur->nxt = prv;
if (cur == end) /* Range includes end; loop must set it too */
break;
}
}