tool/mbed/mbed-sdk/libraries/net/lwip/lwip/core/def.c

   1 /**
   2  * @file
   3  * Common functions used throughout the stack.
   4  *
   5  */
   6
   7 /*
   8  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without modification,
  12  * are permitted provided that the following conditions are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright notice,
  15  *    this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright notice,
  17  *    this list of conditions and the following disclaimer in the documentation
  18  *    and/or other materials provided with the distribution.
  19  * 3. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  25  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  27  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  31  * OF SUCH DAMAGE.
  32  *
  33  * This file is part of the lwIP TCP/IP stack.
  34  *
  35  * Author: Simon Goldschmidt
  36  *
  37  */
  38
  39 #include "lwip/opt.h"
  40 #include "lwip/def.h"
  41
  42 /**
  43  * These are reference implementations of the byte swapping functions.
  44  * Again with the aim of being simple, correct and fully portable.
  45  * Byte swapping is the second thing you would want to optimize. You will
  46  * need to port it to your architecture and in your cc.h:
  47  *
  48  * #define LWIP_PLATFORM_BYTESWAP 1
  49  * #define LWIP_PLATFORM_HTONS(x) <your_htons>
  50  * #define LWIP_PLATFORM_HTONL(x) <your_htonl>
  51  *
  52  * Note ntohs() and ntohl() are merely references to the htonx counterparts.
  53  */
  54
  55 #if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
  56
  57 /**
  58  * Convert an u16_t from host- to network byte order.
  59  *
  60  * @param n u16_t in host byte order
  61  * @return n in network byte order
  62  */
  63 u16_t
  64 lwip_htons(u16_t n)
  65 {
  66   return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
  67 }
  68
  69 /**
  70  * Convert an u16_t from network- to host byte order.
  71  *
  72  * @param n u16_t in network byte order
  73  * @return n in host byte order
  74  */
  75 u16_t
  76 lwip_ntohs(u16_t n)
  77 {
  78   return lwip_htons(n);
  79 }
  80
  81 /**
  82  * Convert an u32_t from host- to network byte order.
  83  *
  84  * @param n u32_t in host byte order
  85  * @return n in network byte order
  86  */
  87 u32_t
  88 lwip_htonl(u32_t n)
  89 {
  90   return ((n & 0xff) << 24) |
  91     ((n & 0xff00) << 8) |
  92     ((n & 0xff0000UL) >> 8) |
  93     ((n & 0xff000000UL) >> 24);
  94 }
  95
  96 /**
  97  * Convert an u32_t from network- to host byte order.
  98  *
  99  * @param n u32_t in network byte order
 100  * @return n in host byte order
 101  */
 102 u32_t
 103 lwip_ntohl(u32_t n)
 104 {
 105   return lwip_htonl(n);
 106 }
 107
 108 #endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */