lib/liblwip/include/lwip/def.h

   1 /*
   2  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without modification,
   6  * are permitted provided that the following conditions are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright notice,
   9  *    this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright notice,
  11  *    this list of conditions and the following disclaimer in the documentation
  12  *    and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  19  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  21  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  24  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  25  * OF SUCH DAMAGE.
  26  *
  27  * This file is part of the lwIP TCP/IP stack.
  28  *
  29  * Author: Adam Dunkels <adam@sics.se>
  30  *
  31  */
  32 #ifndef __LWIP_DEF_H__
  33 #define __LWIP_DEF_H__
  34
  35 /* arch.h might define NULL already */
  36 #include "lwip/arch.h"
  37 #include "lwip/opt.h"
  38
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 #define LWIP_MAX(x , y)  (((x) > (y)) ? (x) : (y))
  44 #define LWIP_MIN(x , y)  (((x) < (y)) ? (x) : (y))
  45
  46 #ifndef NULL
  47 #define NULL ((void *)0)
  48 #endif
  49
  50 /** Get the absolute difference between 2 u32_t values (correcting overflows)
  51  * 'a' is expected to be 'higher' (without overflow) than 'b'. */
  52 #define LWIP_U32_DIFF(a, b) (((a) >= (b)) ? ((a) - (b)) : (((a) + ((b) ^ 0xFFFFFFFF) + 1)))
  53
  54 /* Endianess-optimized shifting of two u8_t to create one u16_t */
  55 #if BYTE_ORDER == LITTLE_ENDIAN
  56 #define LWIP_MAKE_U16(a, b) ((a << 8) | b)
  57 #else
  58 #define LWIP_MAKE_U16(a, b) ((b << 8) | a)
  59 #endif
  60
  61 #ifndef LWIP_PLATFORM_BYTESWAP
  62 #define LWIP_PLATFORM_BYTESWAP 0
  63 #endif
  64
  65 #ifndef LWIP_PREFIX_BYTEORDER_FUNCS
  66 /* workaround for naming collisions on some platforms */
  67
  68 #ifdef htons
  69 #undef htons
  70 #endif /* htons */
  71 #ifdef htonl
  72 #undef htonl
  73 #endif /* htonl */
  74 #ifdef ntohs
  75 #undef ntohs
  76 #endif /* ntohs */
  77 #ifdef ntohl
  78 #undef ntohl
  79 #endif /* ntohl */
  80
  81 #define htons(x) lwip_htons(x)
  82 #define ntohs(x) lwip_ntohs(x)
  83 #define htonl(x) lwip_htonl(x)
  84 #define ntohl(x) lwip_ntohl(x)
  85 #endif /* LWIP_PREFIX_BYTEORDER_FUNCS */
  86
  87 #if BYTE_ORDER == BIG_ENDIAN
  88 #define lwip_htons(x) (x)
  89 #define lwip_ntohs(x) (x)
  90 #define lwip_htonl(x) (x)
  91 #define lwip_ntohl(x) (x)
  92 #define PP_HTONS(x) (x)
  93 #define PP_NTOHS(x) (x)
  94 #define PP_HTONL(x) (x)
  95 #define PP_NTOHL(x) (x)
  96 #else /* BYTE_ORDER != BIG_ENDIAN */
  97 #if LWIP_PLATFORM_BYTESWAP
  98 #define lwip_htons(x) LWIP_PLATFORM_HTONS(x)
  99 #define lwip_ntohs(x) LWIP_PLATFORM_HTONS(x)
 100 #define lwip_htonl(x) LWIP_PLATFORM_HTONL(x)
 101 #define lwip_ntohl(x) LWIP_PLATFORM_HTONL(x)
 102 #else /* LWIP_PLATFORM_BYTESWAP */
 103 u16_t lwip_htons(u16_t x);
 104 u16_t lwip_ntohs(u16_t x);
 105 u32_t lwip_htonl(u32_t x);
 106 u32_t lwip_ntohl(u32_t x);
 107 #endif /* LWIP_PLATFORM_BYTESWAP */
 108
 109 /* These macros should be calculated by the preprocessor and are used
 110    with compile-time constants only (so that there is no little-endian
 111    overhead at runtime). */
 112 #define PP_HTONS(x) ((((x) & 0xff) << 8) | (((x) & 0xff00) >> 8))
 113 #define PP_NTOHS(x) PP_HTONS(x)
 114 #define PP_HTONL(x) ((((x) & 0xff) << 24) | \
 115                      (((x) & 0xff00) << 8) | \
 116                      (((x) & 0xff0000UL) >> 8) | \
 117                      (((x) & 0xff000000UL) >> 24))
 118 #define PP_NTOHL(x) PP_HTONL(x)
 119
 120 #endif /* BYTE_ORDER == BIG_ENDIAN */
 121
 122 #ifdef __cplusplus
 123 }
 124 #endif
 125
 126 #endif /* __LWIP_DEF_H__ */
 127