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Wrote real version of unaligned data access functions (needed for BGP).

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This commit is contained in:
Martin Mares 2000-03-21 15:51:30 +00:00
parent c01e37416d
commit a8f944cb6e
1 changed files with 31 additions and 21 deletions
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52
lib/unaligned.h
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@ -1,7 +1,7 @@
/*
* Unaligned Data Accesses -- Generic Version
* Unaligned Data Accesses -- Generic Version, Network Order
*
* (c) 1998 Martin Mares <mj@ucw.cz>
* (c) 2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
@ -9,34 +9,44 @@
#ifndef _BIRD_UNALIGNED_H_
#define _BIRD_UNALIGNED_H_
#if CPU_NEEDS_ALIGN_WORD != 1 || CPU_NEEDS_ALIGN_LONG != 1
#include <string.h>
#endif
/*
* 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 <string.h>
#if CPU_NEEDS_ALIGN_WORD == 1
#define unaligned_u16(p) (*((u16 *)(p)))
#else
static inline u16
unaligned_u16(void *p)
get_u16(void *p)
{
u16 x;
memcpy(&x, p, sizeof(x));
return x;
memcpy(&x, p, 2);
return ntohs(x);
}
#endif
#if CPU_NEEDS_ALIGN_LONG == 1
#define unaligned_u32(p) (*((u32 *)(p)))
#else
static inline u32
unaligned_u32(void *p)
get_u32(void *p)
{
u32 x;
memcpy(&x, p, sizeof(x));
return x;
memcpy(&x, p, 4);
return ntohl(x);
}
static inline void
put_u16(void *p, u16 x)
{
x = htons(x);
memcpy(p, &x, 2);
}
static inline void
put_u32(void *p, u32 x)
{
x = htonl(x);
memcpy(p, &x, 4);
}
#endif
#endif