include/uapi/linux/swab.h

   1 #ifndef _UAPI_LINUX_SWAB_H
   2 #define _UAPI_LINUX_SWAB_H
   3
   4 #include <linux/types.h>
   5 #include <linux/compiler.h>
   6 #include <asm/swab.h>
   7
   8 /*
   9  * casts are necessary for constants, because we never know how for sure
  10  * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
  11  */
  12 #define ___constant_swab16(x) ((__u16)(                         \
  13         (((__u16)(x) & (__u16)0x00ffU) << 8) |                  \
  14         (((__u16)(x) & (__u16)0xff00U) >> 8)))
  15
  16 #define ___constant_swab32(x) ((__u32)(                         \
  17         (((__u32)(x) & (__u32)0x000000ffUL) << 24) |            \
  18         (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) |            \
  19         (((__u32)(x) & (__u32)0x00ff0000UL) >>  8) |            \
  20         (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
  21
  22 #define ___constant_swab64(x) ((__u64)(                         \
  23         (((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) |   \
  24         (((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) |   \
  25         (((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) |   \
  26         (((__u64)(x) & (__u64)0x00000000ff000000ULL) <<  8) |   \
  27         (((__u64)(x) & (__u64)0x000000ff00000000ULL) >>  8) |   \
  28         (((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) |   \
  29         (((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) |   \
  30         (((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56)))
  31
  32 #define ___constant_swahw32(x) ((__u32)(                        \
  33         (((__u32)(x) & (__u32)0x0000ffffUL) << 16) |            \
  34         (((__u32)(x) & (__u32)0xffff0000UL) >> 16)))
  35
  36 #define ___constant_swahb32(x) ((__u32)(                        \
  37         (((__u32)(x) & (__u32)0x00ff00ffUL) << 8) |             \
  38         (((__u32)(x) & (__u32)0xff00ff00UL) >> 8)))
  39
  40 /*
  41  * Implement the following as inlines, but define the interface using
  42  * macros to allow constant folding when possible:
  43  * ___swab16, ___swab32, ___swab64, ___swahw32, ___swahb32
  44  */
  45
  46 static inline __attribute_const__ __u16 __fswab16(__u16 val)
  47 {
  48 #ifdef __HAVE_BUILTIN_BSWAP16__
  49         return __builtin_bswap16(val);
  50 #elif defined (__arch_swab16)
  51         return __arch_swab16(val);
  52 #else
  53         return ___constant_swab16(val);
  54 #endif
  55 }
  56
  57 static inline __attribute_const__ __u32 __fswab32(__u32 val)
  58 {
  59 #ifdef __HAVE_BUILTIN_BSWAP32__
  60         return __builtin_bswap32(val);
  61 #elif defined(__arch_swab32)
  62         return __arch_swab32(val);
  63 #else
  64         return ___constant_swab32(val);
  65 #endif
  66 }
  67
  68 static inline __attribute_const__ __u64 __fswab64(__u64 val)
  69 {
  70 #ifdef __HAVE_BUILTIN_BSWAP64__
  71         return __builtin_bswap64(val);
  72 #elif defined (__arch_swab64)
  73         return __arch_swab64(val);
  74 #elif defined(__SWAB_64_THRU_32__)
  75         __u32 h = val >> 32;
  76         __u32 l = val & ((1ULL << 32) - 1);
  77         return (((__u64)__fswab32(l)) << 32) | ((__u64)(__fswab32(h)));
  78 #else
  79         return ___constant_swab64(val);
  80 #endif
  81 }
  82
  83 static inline __attribute_const__ __u32 __fswahw32(__u32 val)
  84 {
  85 #ifdef __arch_swahw32
  86         return __arch_swahw32(val);
  87 #else
  88         return ___constant_swahw32(val);
  89 #endif
  90 }
  91
  92 static inline __attribute_const__ __u32 __fswahb32(__u32 val)
  93 {
  94 #ifdef __arch_swahb32
  95         return __arch_swahb32(val);
  96 #else
  97         return ___constant_swahb32(val);
  98 #endif
  99 }
 100
 101 /**
 102  * __swab16 - return a byteswapped 16-bit value
 103  * @x: value to byteswap
 104  */
 105 #define __swab16(x)                             \
 106         (__builtin_constant_p((__u16)(x)) ?     \
 107         ___constant_swab16(x) :                 \
 108         __fswab16(x))
 109
 110 /**
 111  * __swab32 - return a byteswapped 32-bit value
 112  * @x: value to byteswap
 113  */
 114 #define __swab32(x)                             \
 115         (__builtin_constant_p((__u32)(x)) ?     \
 116         ___constant_swab32(x) :                 \
 117         __fswab32(x))
 118
 119 /**
 120  * __swab64 - return a byteswapped 64-bit value
 121  * @x: value to byteswap
 122  */
 123 #define __swab64(x)                             \
 124         (__builtin_constant_p((__u64)(x)) ?     \
 125         ___constant_swab64(x) :                 \
 126         __fswab64(x))
 127
 128 /**
 129  * __swahw32 - return a word-swapped 32-bit value
 130  * @x: value to wordswap
 131  *
 132  * __swahw32(0x12340000) is 0x00001234
 133  */
 134 #define __swahw32(x)                            \
 135         (__builtin_constant_p((__u32)(x)) ?     \
 136         ___constant_swahw32(x) :                \
 137         __fswahw32(x))
 138
 139 /**
 140  * __swahb32 - return a high and low byte-swapped 32-bit value
 141  * @x: value to byteswap
 142  *
 143  * __swahb32(0x12345678) is 0x34127856
 144  */
 145 #define __swahb32(x)                            \
 146         (__builtin_constant_p((__u32)(x)) ?     \
 147         ___constant_swahb32(x) :                \
 148         __fswahb32(x))
 149
 150 /**
 151  * __swab16p - return a byteswapped 16-bit value from a pointer
 152  * @p: pointer to a naturally-aligned 16-bit value
 153  */
 154 static __always_inline __u16 __swab16p(const __u16 *p)
 155 {
 156 #ifdef __arch_swab16p
 157         return __arch_swab16p(p);
 158 #else
 159         return __swab16(*p);
 160 #endif
 161 }
 162
 163 /**
 164  * __swab32p - return a byteswapped 32-bit value from a pointer
 165  * @p: pointer to a naturally-aligned 32-bit value
 166  */
 167 static __always_inline __u32 __swab32p(const __u32 *p)
 168 {
 169 #ifdef __arch_swab32p
 170         return __arch_swab32p(p);
 171 #else
 172         return __swab32(*p);
 173 #endif
 174 }
 175
 176 /**
 177  * __swab64p - return a byteswapped 64-bit value from a pointer
 178  * @p: pointer to a naturally-aligned 64-bit value
 179  */
 180 static __always_inline __u64 __swab64p(const __u64 *p)
 181 {
 182 #ifdef __arch_swab64p
 183         return __arch_swab64p(p);
 184 #else
 185         return __swab64(*p);
 186 #endif
 187 }
 188
 189 /**
 190  * __swahw32p - return a wordswapped 32-bit value from a pointer
 191  * @p: pointer to a naturally-aligned 32-bit value
 192  *
 193  * See __swahw32() for details of wordswapping.
 194  */
 195 static inline __u32 __swahw32p(const __u32 *p)
 196 {
 197 #ifdef __arch_swahw32p
 198         return __arch_swahw32p(p);
 199 #else
 200         return __swahw32(*p);
 201 #endif
 202 }
 203
 204 /**
 205  * __swahb32p - return a high and low byteswapped 32-bit value from a pointer
 206  * @p: pointer to a naturally-aligned 32-bit value
 207  *
 208  * See __swahb32() for details of high/low byteswapping.
 209  */
 210 static inline __u32 __swahb32p(const __u32 *p)
 211 {
 212 #ifdef __arch_swahb32p
 213         return __arch_swahb32p(p);
 214 #else
 215         return __swahb32(*p);
 216 #endif
 217 }
 218
 219 /**
 220  * __swab16s - byteswap a 16-bit value in-place
 221  * @p: pointer to a naturally-aligned 16-bit value
 222  */
 223 static inline void __swab16s(__u16 *p)
 224 {
 225 #ifdef __arch_swab16s
 226         __arch_swab16s(p);
 227 #else
 228         *p = __swab16p(p);
 229 #endif
 230 }
 231 /**
 232  * __swab32s - byteswap a 32-bit value in-place
 233  * @p: pointer to a naturally-aligned 32-bit value
 234  */
 235 static __always_inline void __swab32s(__u32 *p)
 236 {
 237 #ifdef __arch_swab32s
 238         __arch_swab32s(p);
 239 #else
 240         *p = __swab32p(p);
 241 #endif
 242 }
 243
 244 /**
 245  * __swab64s - byteswap a 64-bit value in-place
 246  * @p: pointer to a naturally-aligned 64-bit value
 247  */
 248 static __always_inline void __swab64s(__u64 *p)
 249 {
 250 #ifdef __arch_swab64s
 251         __arch_swab64s(p);
 252 #else
 253         *p = __swab64p(p);
 254 #endif
 255 }
 256
 257 /**
 258  * __swahw32s - wordswap a 32-bit value in-place
 259  * @p: pointer to a naturally-aligned 32-bit value
 260  *
 261  * See __swahw32() for details of wordswapping
 262  */
 263 static inline void __swahw32s(__u32 *p)
 264 {
 265 #ifdef __arch_swahw32s
 266         __arch_swahw32s(p);
 267 #else
 268         *p = __swahw32p(p);
 269 #endif
 270 }
 271
 272 /**
 273  * __swahb32s - high and low byteswap a 32-bit value in-place
 274  * @p: pointer to a naturally-aligned 32-bit value
 275  *
 276  * See __swahb32() for details of high and low byte swapping
 277  */
 278 static inline void __swahb32s(__u32 *p)
 279 {
 280 #ifdef __arch_swahb32s
 281         __arch_swahb32s(p);
 282 #else
 283         *p = __swahb32p(p);
 284 #endif
 285 }
 286
 287
 288 #endif /* _UAPI_LINUX_SWAB_H */