mdw@git.distorted.org.uk Git - secnet/blob - unaligned.h

   1 #ifndef unaligned_h
   2 #define unaligned_h
   3
   4 #include <stdint.h>
   5 #include "util.h"
   6
   7 /* Parts of the secnet key-exchange protocol require access to
   8    unaligned big-endian quantities in buffers. These macros provide
   9    convenient access, even on architectures that don't support unaligned
  10    accesses. */
  11
  12 #define put_uint32(a,v) do { (a)[0]=(v)>>24; (a)[1]=((v)&0xff0000)>>16; \
  13 (a)[2]=((v)&0xff00)>>8; (a)[3]=(v)&0xff; } while(0)
  14
  15 #define put_uint16(a,v) do {(a)[0]=((v)&0xff00)>>8; (a)[1]=(v)&0xff;} while(0)
  16
  17 #define put_uint8(a,v) do {(a)[0]=((v)&0xff);} while(0)
  18
  19 #define get_uint32(a)                                   \
  20   (((uint32_t)(a)[0]<<24) | ((uint32_t)(a)[1]<<16) |    \
  21    ((uint32_t)(a)[2]<<8)  |  (uint32_t)(a)[3])
  22
  23 #define get_uint16(a) (((uint16_t)(a)[0]<<8)|(uint16_t)(a)[1])
  24
  25 #define get_uint8(a) (((uint8_t)(a)[0]))
  26
  27 #define UNALIGNED_DEF_FORTYPE(type,appre)                               \
  28 static inline void buf_##appre##_##type(struct buffer_if *buf, type##_t v) \
  29 {                                                                       \
  30     uint8_t *c=buf_##appre(buf,sizeof(type##_t));                       \
  31     put_##type(c,v);                                                    \
  32 }                                                                       \
  33 static inline type##_t buf_un##appre##_##type(struct buffer_if *buf)    \
  34 {                                                                       \
  35     const uint8_t *c=buf_un##appre(buf,sizeof(type##_t));               \
  36     return get_##type(c);                                               \
  37 }
  38
  39 UNALIGNED_DEF_FORTYPE(uint32,append)
  40 UNALIGNED_DEF_FORTYPE(uint16,append)
  41 UNALIGNED_DEF_FORTYPE(uint8,append)
  42 UNALIGNED_DEF_FORTYPE(uint32,prepend)
  43 UNALIGNED_DEF_FORTYPE(uint16,prepend)
  44 UNALIGNED_DEF_FORTYPE(uint8,prepend)
  45
  46 #endif /* unaligned_h */