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
40extern "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 */
103u16_t lwip_htons(u16_t x);
104u16_t lwip_ntohs(u16_t x);
105u32_t lwip_htonl(u32_t x);
106u32_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
128