对于目标机是大端字节序的机器，进行字节码的转换，提供了16byte、32byte、64byte字节的转换。在intset\ziplist\zipmap三种数据结构中使用，使得不同字节序机器生成的rdb文件格式都是统一的（小端字节序），便于兼容。
代码实在是太简单了，贴上来，不多说了。
endian.h
1
#ifndef __ENDIAN_H
2
#define
__ENDIAN_H
3
4
void
memrev16(
void
*
p);
5
void
memrev32(
void
*
p);
6
void
memrev64(
void
*
p);
7
8
/*
variants of the function doing the actual convertion only if the target
9
* host is big endian
*/
10
#if
(BYTE_ORDER == LITTLE_ENDIAN)
11
#define
memrev16ifbe(p)
12
#define
memrev32ifbe(p)
13
#define
memrev64ifbe(p)
14
#else
15
#define
memrev16ifbe(p) memrev16(p)
16
#define
memrev32ifbe(p) memrev32(p)
17
#define
memrev64ifbe(p) memrev64(p)
18
#endif
19
20
#endif
endian.c
1
/*
Toggle the 16 bit unsigned integer pointed by *p from little endian to
2
* big endian
*/
3
void
memrev16(
void
*
p) {
4
unsigned
char
*x =
p, t;
5
6
t = x[
0
];
7
x[
0
] = x[
1
];
8
x[
1
] =
t;
9
}
10
11
/*
Toggle the 32 bit unsigned integer pointed by *p from little endian to
12
* big endian
*/
13
void
memrev32(
void
*
p) {
14
unsigned
char
*x =
p, t;
15
16
t = x[
0
];
17
x[
0
] = x[
3
];
18
x[
3
] =
t;
19
t = x[
1
];
20
x[
1
] = x[
2
];
21
x[
2
] =
t;
22
}
23
24
/*
Toggle the 64 bit unsigned integer pointed by *p from little endian to
25
* big endian
*/
26
void
memrev64(
void
*
p) {
27
unsigned
char
*x =
p, t;
28
29
t = x[
0
];
30
x[
0
] = x[
7
];
31
x[
7
] =
t;
32
t = x[
1
];
33
x[
1
] = x[
6
];
34
x[
6
] =
t;
35
t = x[
2
];
36
x[
2
] = x[
5
];
37
x[
5
] =
t;
38
t = x[
3
];
39
x[
3
] = x[
4
];
40
x[
4
] =
t;
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}
42
43
#ifdef TESTMAIN
44
#include <stdio.h>
45
46
int
main(
void
) {
47
char
buf[
32
];
48
49
sprintf(buf,
"
ciaoroma
"
);
50
memrev16(buf);
51
printf(
"
%s\n
"
, buf);
52
53
sprintf(buf,
"
ciaoroma
"
);
54
memrev32(buf);
55
printf(
"
%s\n
"
, buf);
56
57
sprintf(buf,
"
ciaoroma
"
);
58
memrev64(buf);
59
printf(
"
%s\n
"
, buf);
60
61
return
0
;
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}
63
#endif
