def.h

00001 /*
00002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00003  * All rights reserved. 
00004  * 
00005  * Redistribution and use in source and binary forms, with or without modification, 
00006  * are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright notice,
00009  *    this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright notice,
00011  *    this list of conditions and the following disclaimer in the documentation
00012  *    and/or other materials provided with the distribution.
00013  * 3. The name of the author may not be used to endorse or promote products
00014  *    derived from this software without specific prior written permission. 
00015  *
00016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00025  * OF SUCH DAMAGE.
00026  *
00027  * This file is part of the lwIP TCP/IP stack.
00028  * 
00029  * Author: Adam Dunkels <adam@sics.se>
00030  *
00031  */
00032 #ifndef __LWIP_DEF_H__
00033 #define __LWIP_DEF_H__
00034 
00035 /* arch.h might define NULL already */
00036 #include "lwip/arch.h"
00037 #include "lwip/opt.h"
00038 
00039 #ifdef __cplusplus
00040 extern "C" {
00041 #endif
00042 
00043 #define LWIP_MAX(x , y)  (((x) > (y)) ? (x) : (y))
00044 #define LWIP_MIN(x , y)  (((x) < (y)) ? (x) : (y))
00045 
00046 #ifndef NULL
00047 #define NULL ((void *)0)
00048 #endif
00049 
00050 /** Get the absolute difference between 2 u32_t values (correcting overflows)
00051  * 'a' is expected to be 'higher' (without overflow) than 'b'. */
00052 #define LWIP_U32_DIFF(a, b) (((a) >= (b)) ? ((a) - (b)) : (((a) + ((b) ^ 0xFFFFFFFF) + 1))) 
00053 
00054 /* Endianess-optimized shifting of two u8_t to create one u16_t */
00055 #if BYTE_ORDER == LITTLE_ENDIAN
00056 #define LWIP_MAKE_U16(a, b) ((a << 8) | b)
00057 #else
00058 #define LWIP_MAKE_U16(a, b) ((b << 8) | a)
00059 #endif 
00060 
00061 #ifndef LWIP_PLATFORM_BYTESWAP
00062 #define LWIP_PLATFORM_BYTESWAP 0
00063 #endif
00064 
00065 #ifndef LWIP_PREFIX_BYTEORDER_FUNCS
00066 /* workaround for naming collisions on some platforms */
00067 
00068 #ifdef htons
00069 #undef htons
00070 #endif /* htons */
00071 #ifdef htonl
00072 #undef htonl
00073 #endif /* htonl */
00074 #ifdef ntohs
00075 #undef ntohs
00076 #endif /* ntohs */
00077 #ifdef ntohl
00078 #undef ntohl
00079 #endif /* ntohl */
00080 
00081 #define htons(x) lwip_htons(x)
00082 #define ntohs(x) lwip_ntohs(x)
00083 #define htonl(x) lwip_htonl(x)
00084 #define ntohl(x) lwip_ntohl(x)
00085 #endif /* LWIP_PREFIX_BYTEORDER_FUNCS */
00086 
00087 #if BYTE_ORDER == BIG_ENDIAN
00088 #define lwip_htons(x) (x)
00089 #define lwip_ntohs(x) (x)
00090 #define lwip_htonl(x) (x)
00091 #define lwip_ntohl(x) (x)
00092 #define PP_HTONS(x) (x)
00093 #define PP_NTOHS(x) (x)
00094 #define PP_HTONL(x) (x)
00095 #define PP_NTOHL(x) (x)
00096 #else /* BYTE_ORDER != BIG_ENDIAN */
00097 #if LWIP_PLATFORM_BYTESWAP
00098 #define lwip_htons(x) LWIP_PLATFORM_HTONS(x)
00099 #define lwip_ntohs(x) LWIP_PLATFORM_HTONS(x)
00100 #define lwip_htonl(x) LWIP_PLATFORM_HTONL(x)
00101 #define lwip_ntohl(x) LWIP_PLATFORM_HTONL(x)
00102 #else /* LWIP_PLATFORM_BYTESWAP */
00103 u16_t lwip_htons(u16_t x);
00104 u16_t lwip_ntohs(u16_t x);
00105 u32_t lwip_htonl(u32_t x);
00106 u32_t lwip_ntohl(u32_t x);
00107 #endif /* LWIP_PLATFORM_BYTESWAP */
00108 
00109 /* These macros should be calculated by the preprocessor and are used
00110    with compile-time constants only (so that there is no little-endian
00111    overhead at runtime). */
00112 #define PP_HTONS(x) ((((x) & 0xff) << 8) | (((x) & 0xff00) >> 8))
00113 #define PP_NTOHS(x) PP_HTONS(x)
00114 #define PP_HTONL(x) ((((x) & 0xff) << 24) | \
00115                      (((x) & 0xff00) << 8) | \
00116                      (((x) & 0xff0000UL) >> 8) | \
00117                      (((x) & 0xff000000UL) >> 24))
00118 #define PP_NTOHL(x) PP_HTONL(x)
00119 
00120 #endif /* BYTE_ORDER == BIG_ENDIAN */
00121 
00122 #ifdef __cplusplus
00123 }
00124 #endif
00125 
00126 #endif /* __LWIP_DEF_H__ */
00127