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99 lines
2.6 KiB
C
99 lines
2.6 KiB
C
/*
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* Unaligned Data Accesses -- Generic Version, Network Order
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*
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* (c) 2000 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_UNALIGNED_H_
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#define _BIRD_UNALIGNED_H_
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/*
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* We don't do any clever tricks with unaligned accesses since it's
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* virtually impossible to figure out what alignment does the CPU want
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* (unaligned accesses can be emulated by the OS which makes them work,
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* but unusably slow). We use memcpy and hope GCC will optimize it out
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* if possible.
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*/
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#include "lib/string.h"
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#include <netinet/in.h>
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static inline u16
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get_u16(void *p)
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{
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u16 x;
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memcpy(&x, p, 2);
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return ntohs(x);
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}
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static inline u32
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get_u32(void *p)
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{
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u32 x;
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memcpy(&x, p, 4);
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return ntohl(x);
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}
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static inline void
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put_u16(void *p, u16 x)
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{
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x = htons(x);
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memcpy(p, &x, 2);
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}
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static inline void
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put_u32(void *p, u32 x)
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{
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x = htonl(x);
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memcpy(p, &x, 4);
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}
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/* Big endian format */
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#if defined(CPU_BIG_ENDIAN)
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static inline uint get_u16_be(const void *p) { return *(u16 *)p; } /** Read 16-bit integer value from an unaligned sequence of 2 bytes (big-endian version). **/
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static inline u32 get_u32_be(const void *p) { return *(u32 *)p; } /** Read 32-bit integer value from an unaligned sequence of 4 bytes (big-endian version). **/
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static inline u64 get_u64_be(const void *p) { return *(u64 *)p; } /** Read 64-bit integer value from an unaligned sequence of 8 bytes (big-endian version). **/
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static inline void put_u16_be(void *p, uint x) { *(u16 *)p = x; } /** Write 16-bit integer value to an unaligned sequence of 2 bytes (big-endian version). **/
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static inline void put_u32_be(void *p, u32 x) { *(u32 *)p = x; } /** Write 32-bit integer value to an unaligned sequence of 4 bytes (big-endian version). **/
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static inline void put_u64_be(void *p, u64 x) { *(u64 *)p = x; } /** Write 64-bit integer value to an unaligned sequence of 8 bytes (big-endian version). **/
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#else
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static inline uint get_u16_be(const void *p)
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{
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const byte *c = (const byte *)p;
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return (c[0] << 8) | c[1];
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}
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static inline u32 get_u32_be(const void *p)
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{
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const byte *c = (const byte *)p;
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return (c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3];
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}
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static inline u64 get_u64_be(const void *p)
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{
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return ((u64) get_u32_be(p) << 32) | get_u32_be((const byte *)p+4);
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}
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static inline void put_u16_be(void *p, uint x)
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{
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byte *c = (byte *)p;
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c[0] = x >> 8;
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c[1] = x;
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}
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static inline void put_u32_be(void *p, u32 x)
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{
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byte *c = (byte *)p;
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c[0] = x >> 24;
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c[1] = x >> 16;
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c[2] = x >> 8;
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c[3] = x;
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}
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static inline void put_u64_be(void *p, u64 x)
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{
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put_u32_be(p, x >> 32);
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put_u32_be((byte *)p+4, x);
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}
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#endif
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#endif
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