lwip/src/core/def.c

109 lines
3.1 KiB
C

/**
* @file
* Common functions used throughout the stack.
*
*/
/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Simon Goldschmidt
*
*/
#include "lwip/opt.h"
#include "lwip/def.h"
/**
* These are reference implementations of the byte swapping functions.
* Again with the aim of being simple, correct and fully portable.
* Byte swapping is the second thing you would want to optimize. You will
* need to port it to your architecture and in your cc.h:
*
* #define LWIP_PLATFORM_BYTESWAP 1
* #define LWIP_PLATFORM_HTONS(x) <your_htons>
* #define LWIP_PLATFORM_HTONL(x) <your_htonl>
*
* Note ntohs() and ntohl() are merely references to the htonx counterparts.
*/
#if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
/**
* Convert an u16_t from host- to network byte order.
*
* @param n u16_t in host byte order
* @return n in network byte order
*/
u16_t
lwip_htons(u16_t n)
{
return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
}
/**
* Convert an u16_t from network- to host byte order.
*
* @param n u16_t in network byte order
* @return n in host byte order
*/
u16_t
lwip_ntohs(u16_t n)
{
return lwip_htons(n);
}
/**
* Convert an u32_t from host- to network byte order.
*
* @param n u32_t in host byte order
* @return n in network byte order
*/
u32_t
lwip_htonl(u32_t n)
{
return ((n & 0xff) << 24) |
((n & 0xff00) << 8) |
((n & 0xff0000UL) >> 8) |
((n & 0xff000000UL) >> 24);
}
/**
* Convert an u32_t from network- to host byte order.
*
* @param n u32_t in network byte order
* @return n in host byte order
*/
u32_t
lwip_ntohl(u32_t n)
{
return lwip_htonl(n);
}
#endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */