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
|
/*-------------------------------------------------------------------------
*
* pg_bswap.h
* Byte swapping.
*
* Macros for reversing the byte order of 16, 32 and 64-bit unsigned integers.
* For example, 0xAABBCCDD becomes 0xDDCCBBAA. These are just wrappers for
* built-in functions provided by the compiler where support exists.
*
* Note that all of these functions accept unsigned integers as arguments and
* return the same. Use caution when using these wrapper macros with signed
* integers.
*
* Copyright (c) 2015-2023, PostgreSQL Global Development Group
*
* src/include/port/pg_bswap.h
*
*-------------------------------------------------------------------------
*/
#ifndef PG_BSWAP_H
#define PG_BSWAP_H
/*
* In all supported versions msvc provides _byteswap_* functions in stdlib.h,
* already included by c.h.
*/
/* implementation of uint16 pg_bswap16(uint16) */
#if defined(HAVE__BUILTIN_BSWAP16)
#define pg_bswap16(x) __builtin_bswap16(x)
#elif defined(_MSC_VER)
#define pg_bswap16(x) _byteswap_ushort(x)
#else
static inline uint16
pg_bswap16(uint16 x)
{
return
((x << 8) & 0xff00) |
((x >> 8) & 0x00ff);
}
#endif /* HAVE__BUILTIN_BSWAP16 */
/* implementation of uint32 pg_bswap32(uint32) */
#if defined(HAVE__BUILTIN_BSWAP32)
#define pg_bswap32(x) __builtin_bswap32(x)
#elif defined(_MSC_VER)
#define pg_bswap32(x) _byteswap_ulong(x)
#else
static inline uint32
pg_bswap32(uint32 x)
{
return
((x << 24) & 0xff000000) |
((x << 8) & 0x00ff0000) |
((x >> 8) & 0x0000ff00) |
((x >> 24) & 0x000000ff);
}
#endif /* HAVE__BUILTIN_BSWAP32 */
/* implementation of uint64 pg_bswap64(uint64) */
#if defined(HAVE__BUILTIN_BSWAP64)
#define pg_bswap64(x) __builtin_bswap64(x)
#elif defined(_MSC_VER)
#define pg_bswap64(x) _byteswap_uint64(x)
#else
static inline uint64
pg_bswap64(uint64 x)
{
return
((x << 56) & UINT64CONST(0xff00000000000000)) |
((x << 40) & UINT64CONST(0x00ff000000000000)) |
((x << 24) & UINT64CONST(0x0000ff0000000000)) |
((x << 8) & UINT64CONST(0x000000ff00000000)) |
((x >> 8) & UINT64CONST(0x00000000ff000000)) |
((x >> 24) & UINT64CONST(0x0000000000ff0000)) |
((x >> 40) & UINT64CONST(0x000000000000ff00)) |
((x >> 56) & UINT64CONST(0x00000000000000ff));
}
#endif /* HAVE__BUILTIN_BSWAP64 */
/*
* Portable and fast equivalents for ntohs, ntohl, htons, htonl,
* additionally extended to 64 bits.
*/
#ifdef WORDS_BIGENDIAN
#define pg_hton16(x) (x)
#define pg_hton32(x) (x)
#define pg_hton64(x) (x)
#define pg_ntoh16(x) (x)
#define pg_ntoh32(x) (x)
#define pg_ntoh64(x) (x)
#else
#define pg_hton16(x) pg_bswap16(x)
#define pg_hton32(x) pg_bswap32(x)
#define pg_hton64(x) pg_bswap64(x)
#define pg_ntoh16(x) pg_bswap16(x)
#define pg_ntoh32(x) pg_bswap32(x)
#define pg_ntoh64(x) pg_bswap64(x)
#endif /* WORDS_BIGENDIAN */
/*
* Rearrange the bytes of a Datum from big-endian order into the native byte
* order. On big-endian machines, this does nothing at all. Note that the C
* type Datum is an unsigned integer type on all platforms.
*
* One possible application of the DatumBigEndianToNative() macro is to make
* bitwise comparisons cheaper. A simple 3-way comparison of Datums
* transformed by the macro (based on native, unsigned comparisons) will return
* the same result as a memcmp() of the corresponding original Datums, but can
* be much cheaper. It's generally safe to do this on big-endian systems
* without any special transformation occurring first.
*
* If SIZEOF_DATUM is not defined, then postgres.h wasn't included and these
* macros probably shouldn't be used, so we define nothing. Note that
* SIZEOF_DATUM == 8 would evaluate as 0 == 8 in that case, potentially
* leading to the wrong implementation being selected and confusing errors, so
* defining nothing is safest.
*/
#ifdef SIZEOF_DATUM
#ifdef WORDS_BIGENDIAN
#define DatumBigEndianToNative(x) (x)
#else /* !WORDS_BIGENDIAN */
#if SIZEOF_DATUM == 8
#define DatumBigEndianToNative(x) pg_bswap64(x)
#else /* SIZEOF_DATUM != 8 */
#define DatumBigEndianToNative(x) pg_bswap32(x)
#endif /* SIZEOF_DATUM == 8 */
#endif /* WORDS_BIGENDIAN */
#endif /* SIZEOF_DATUM */
#endif /* PG_BSWAP_H */
|
