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
|
/* sort.h
* Copyright 1984-2017 Cisco Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define mkmergesort(sort, merge, type, nil, lt, cdr)\
type sort(type ls, uptr len) {\
if (len == 1) {\
cdr(ls) = nil;\
return ls;\
} else {\
uptr head_len, i; type tail;\
head_len = len >> 1;\
for (tail = ls, i = head_len; i != 0; i -= 1) tail = cdr(tail);\
return merge(sort(ls, head_len), sort(tail, len - head_len));\
}\
}\
type merge(type ls1, type ls2) {\
type p; type *pp = &p;\
for (;;) {\
if (ls1 == nil) { *pp = ls2; break; }\
if (ls2 == nil) { *pp = ls1; break; }\
if (lt(ls2, ls1))\
{ *pp = ls2; pp = &cdr(ls2); ls2 = cdr(ls2); }\
else\
{ *pp = ls1; pp = &cdr(ls1); ls1 = cdr(ls1); }\
}\
return p;\
}
|
