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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. * Can be freely distributed and used under the terms of the GNU GPL.
*/ */
@ -9,34 +9,44 @@
#ifndef _BIRD_UNALIGNED_H_ #ifndef _BIRD_UNALIGNED_H_
#define _BIRD_UNALIGNED_H_ #define _BIRD_UNALIGNED_H_
#if CPU_NEEDS_ALIGN_WORD != 1 || CPU_NEEDS_ALIGN_LONG != 1 /*
#include <string.h> * We don't do any clever tricks with unaligned accesses since it's
#endif * 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 static inline u16
unaligned_u16(void *p) get_u16(void *p)
{ {
u16 x; u16 x;
memcpy(&x, p, 2);
memcpy(&x, p, sizeof(x)); return ntohs(x);
return x;
} }
#endif
#if CPU_NEEDS_ALIGN_LONG == 1
#define unaligned_u32(p) (*((u32 *)(p)))
#else
static inline u32 static inline u32
unaligned_u32(void *p) get_u32(void *p)
{ {
u32 x; u32 x;
memcpy(&x, p, 4);
memcpy(&x, p, sizeof(x)); return ntohl(x);
return 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 #endif