endian.h
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1 /*
2  * SPDX-FileCopyrightText: 2024 Otto-von-Guericke-Universität Magdeburg
3  * SPDX-License-Identifier: LGPL-2.1-only
4  */
5 
6 #pragma once
7 
22 #include <stdint.h>
23 
24 #ifdef __cplusplus
25 extern "C" {
26 #endif
27 
28 #ifdef DOXYGEN
32 #define LITTLE_ENDIAN magic-number
33 
37 #define BIG_ENDIAN magic-number
38 
42 #define PDP_ENDIAN magic-number
43 
52 #define BYTE_ORDER <LITTLE_ENDIAN or BIG_ENDIAN>
53 
54 uint16_t htobe16(uint16_t host_16bits);
55 uint16_t htole16(uint16_t host_16bits);
56 uint16_t be16toh(uint16_t big_endian_16bits);
57 uint16_t le16toh(uint16_t little_endian_16bits);
59 uint32_t htobe32(uint32_t host_32bits);
60 uint32_t htole32(uint32_t host_32bits);
61 uint32_t be32toh(uint32_t big_endian_32bits);
62 uint32_t le32toh(uint32_t little_endian_32bits);
64 uint64_t htobe64(uint64_t host_64bits);
65 uint64_t htole64(uint64_t host_64bits);
66 uint64_t be64toh(uint64_t big_endian_64bits);
67 uint64_t le64toh(uint64_t little_endian_64bits);
69 #else /* DOXYGEN */
70 
71 /* Depending on the version of newlib used, newlib may provide them indirectly
72  * as well. We don't want to redefine them in this case */
73 #ifndef LITTLE_ENDIAN
74 # define LITTLE_ENDIAN 1234
75 #endif
76 #ifndef BIG_ENDIAN
77 # define BIG_ENDIAN 4321
78 #endif
79 #ifndef PDP_ENDIAN
80 # define PDP_ENDIAN 3412
81 #endif
82 #ifndef BYTE_ORDER
83 # define BYTE_ORDER __BYTE_ORDER__
84 #endif
85 
86 /* But to avoid lots of pain in the ass: Let's at least make sure everyone
87  * agrees on what magic number is what */
88 #if (LITTLE_ENDIAN != 1234) || (BIG_ENDIAN != 4321) || (PDP_ENDIAN != 3412)
89 # error "Mismatching magic numbers to refer to endianness"
90 #endif
91 
92 #if BYTE_ORDER == LITTLE_ENDIAN
93 # ifndef htobe16
94 # define htobe16(_x) __builtin_bswap16(_x)
95 # endif
96 # ifndef htole16
97 # define htole16(_x) ((uint16_t)(_x))
98 # endif
99 # ifndef be16toh
100 # define be16toh(_x) __builtin_bswap16(_x)
101 # endif
102 # ifndef le16toh
103 # define le16toh(_x) ((uint16_t)(_x))
104 # endif
105 # ifndef htobe32
106 # define htobe32(_x) __builtin_bswap32(_x)
107 # endif
108 # ifndef htole32
109 # define htole32(_x) ((uint32_t)(_x))
110 # endif
111 # ifndef be32toh
112 # define be32toh(_x) __builtin_bswap32(_x)
113 # endif
114 # ifndef le32toh
115 # define le32toh(_x) ((uint32_t)(_x))
116 # endif
117 # ifndef htobe64
118 # define htobe64(_x) __builtin_bswap64(_x)
119 # endif
120 # ifndef htole64
121 # define htole64(_x) ((uint64_t)(_x))
122 # endif
123 # ifndef be64toh
124 # define be64toh(_x) __builtin_bswap64(_x)
125 # endif
126 # ifndef le64toh
127 # define le64toh(_x) ((uint64_t)(_x))
128 # endif
129 #elif BYTE_ORDER == BIG_ENDIAN
130 # ifndef htole16
131 # define htole16(_x) __builtin_bswap16(_x)
132 # endif
133 # ifndef htobe16
134 # define htobe16(_x) ((uint16_t)(_x))
135 # endif
136 # ifndef le16toh
137 # define le16toh(_x) __builtin_bswap16(_x)
138 # endif
139 # ifndef be16toh
140 # define be16toh(_x) ((uint16_t)(_x))
141 # endif
142 # ifndef htole32
143 # define htole32(_x) __builtin_bswap32(_x)
144 # endif
145 # ifndef htobe32
146 # define htobe32(_x) ((uint32_t)(_x))
147 # endif
148 # ifndef le32toh
149 # define le32toh(_x) __builtin_bswap32(_x)
150 # endif
151 # ifndef be32toh
152 # define be32toh(_x) ((uint32_t)(_x))
153 # endif
154 # ifndef htole64
155 # define htole64(_x) __builtin_bswap64(_x)
156 # endif
157 # ifndef htobe64
158 # define htobe64(_x) ((uint64_t)(_x))
159 # endif
160 # ifndef le64toh
161 # define le64toh(_x) __builtin_bswap64(_x)
162 # endif
163 # ifndef be64toh
164 # define be64toh(_x) ((uint64_t)(_x))
165 # endif
166 #else
167 # error "Byte order not supported"
168 #endif
169 
170 #endif /* DOXYGEN */
171 
172 #ifdef __cplusplus
173 }
174 #endif
175 
be16toh
uint16_t be16toh(uint16_t big_endian_16bits)
big endian to host, 16 bit
htobe16
uint16_t htobe16(uint16_t host_16bits)
host to big endian, 16 bit
le32toh
uint32_t le32toh(uint32_t little_endian_32bits)
little endian to host, 32 bit
htobe32
uint32_t htobe32(uint32_t host_32bits)
host to big endian, 32 bit
le16toh
uint16_t le16toh(uint16_t little_endian_16bits)
little endian to host, 16 bit
htobe64
uint64_t htobe64(uint64_t host_64bits)
host to big endian, 64 bit
be64toh
uint64_t be64toh(uint64_t big_endian_64bits)
big endian to host, 64 bit
be32toh
uint32_t be32toh(uint32_t big_endian_32bits)
big endian to host, 32 bit
htole64
uint64_t htole64(uint64_t host_64bits)
host to little endian, 64 bit
htole32
uint32_t htole32(uint32_t host_32bits)
host to little endian, 32 bit
htole16
uint16_t htole16(uint16_t host_16bits)
host to little endian, 16 bit
le64toh
uint64_t le64toh(uint64_t little_endian_64bits)
little endian to host, 64 bit