bird/lib/unaligned.h

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/*
* Unaligned Data Accesses -- Generic Version, Network Order
*
* (c) 2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef _BIRD_UNALIGNED_H_
#define _BIRD_UNALIGNED_H_
/*
* We don't do any clever tricks with unaligned accesses since it's
* virtually impossible to figure out what alignment does the CPU want
* (unaligned accesses can be emulated by the OS which makes them work,
* but unusably slow). We use memcpy and hope GCC will optimize it out
* if possible.
*/
#include "sysdep/unix/endian.h"
#include "lib/string.h"
static inline u16
get_u16(const void *p)
{
u16 x;
memcpy(&x, p, 2);
return ntohs(x);
}
static inline u32
get_u24(const void *P)
{
const byte *p = P;
return (p[0] << 16) + (p[1] << 8) + p[2];
}
static inline u32
get_u32(const void *p)
{
u32 x;
memcpy(&x, p, 4);
return ntohl(x);
}
static inline u64
get_u64(const void *p)
{
u32 xh, xl;
memcpy(&xh, p, 4);
memcpy(&xl, p+4, 4);
return (((u64) ntohl(xh)) << 32) | ntohl(xl);
}
static inline void
put_u16(void *p, u16 x)
{
x = htons(x);
memcpy(p, &x, 2);
}
static inline void
put_u24(void *p, u32 x)
{
x = htonl(x);
memcpy(p, ((char *) &x) + 1, 3);
}
static inline void
put_u32(void *p, u32 x)
{
x = htonl(x);
memcpy(p, &x, 4);
}
static inline void
put_u64(void *p, u64 x)
{
u32 xh, xl;
xh = htonl(x >> 32);
xl = htonl((u32) x);
memcpy(p, &xh, 4);
memcpy(p+4, &xl, 4);
}
static inline void
get_u32s(const void *p, u32 *x, int n)
{
int i;
memcpy(x, p, 4*n);
for (i = 0; i < n; i++)
x[i] = ntohl(x[i]);
}
static inline void
put_u32s(void *p, const u32 *x, int n)
{
int i;
for (i = 0; i < n; i++)
put_u32((byte *) p + 4*i, x[i]);
}
#endif