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1 /**
2  * @file
3  * Common functions used throughout the stack.
4  *
5  * These are reference implementations of the byte swapping functions.
6  * Again with the aim of being simple, correct and fully portable.
7  * Byte swapping is the second thing you would want to optimize. You will
8  * need to port it to your architecture and in your cc.h:
9  *
10  * \#define lwip_htons(x) your_htons
11  * \#define lwip_htonl(x) your_htonl
12  *
13  * Note lwip_ntohs() and lwip_ntohl() are merely references to the htonx counterparts.
14  *
15  * If you \#define them to htons() and htonl(), you should
16  * \#define LWIP_DONT_PROVIDE_BYTEORDER_FUNCTIONS to prevent lwIP from
17  * defining htonx/ntohx compatibility macros.
18 
19  * @defgroup sys_nonstandard Non-standard functions
20  * @ingroup sys_layer
21  * lwIP provides default implementations for non-standard functions.
22  * These can be mapped to OS functions to reduce code footprint if desired.
23  * All defines related to this section must not be placed in lwipopts.h,
24  * but in arch/cc.h!
25  * These options cannot be \#defined in lwipopts.h since they are not options
26  * of lwIP itself, but options of the lwIP port to your system.
27  */
28 
29 /*
30  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
31  * All rights reserved.
32  *
33  * Redistribution and use in source and binary forms, with or without modification,
34  * are permitted provided that the following conditions are met:
35  *
36  * 1. Redistributions of source code must retain the above copyright notice,
37  *    this list of conditions and the following disclaimer.
38  * 2. Redistributions in binary form must reproduce the above copyright notice,
39  *    this list of conditions and the following disclaimer in the documentation
40  *    and/or other materials provided with the distribution.
41  * 3. The name of the author may not be used to endorse or promote products
42  *    derived from this software without specific prior written permission.
43  *
44  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
45  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
46  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
47  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
48  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
49  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
50  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
51  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
52  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
53  * OF SUCH DAMAGE.
54  *
55  * This file is part of the lwIP TCP/IP stack.
56  *
57  * Author: Simon Goldschmidt
58  *
59  */
60 
61 #include "lwip/opt.h"
62 #include "lwip/def.h"
63 
64 #include <string.h>
65 
66 #if BYTE_ORDER == LITTLE_ENDIAN
67 
68 #if !defined(lwip_htons)
69 /**
70  * Convert an u16_t from host- to network byte order.
71  *
72  * @param n u16_t in host byte order
73  * @return n in network byte order
74  */
75 u16_t
lwip_htons(u16_t n)76 lwip_htons(u16_t n)
77 {
78   return PP_HTONS(n);
79 }
80 #endif /* lwip_htons */
81 
82 #if !defined(lwip_ntohs)
83 /*
84  * Convert an u16_t from network- to host byte order.
85  *
86  * @param n u16_t in network byte order
87  * @return n in host byte order
88  */
89 u16_t
lwip_ntohs(u16_t n)90 lwip_ntohs(u16_t n)
91 {
92   return lwip_htons(n);
93 }
94 #endif
95 
96 #if !defined(lwip_htonl)
97 /**
98  * Convert an u32_t from host- to network byte order.
99  *
100  * @param n u32_t in host byte order
101  * @return n in network byte order
102  */
103 u32_t
lwip_htonl(u32_t n)104 lwip_htonl(u32_t n)
105 {
106   return PP_HTONL(n);
107 }
108 #endif /* lwip_htonl */
109 
110 #if !defined(lwip_ntohl)
111 /*
112  * Convert an u32_t from network- to host byte order.
113  *
114  * @param n u32_t in network byte order
115  * @return n in host byte order
116  */
117 u32_t
lwip_ntohl(u32_t n)118 lwip_ntohl(u32_t n)
119 {
120   return lwip_htonl(n);
121 }
122 #endif /* lwip_htonl */
123 
124 #endif /* BYTE_ORDER == LITTLE_ENDIAN */
125 
126 #ifndef lwip_strnstr
127 /**
128  * @ingroup sys_nonstandard
129  * lwIP default implementation for strnstr() non-standard function.
130  * This can be \#defined to strnstr() depending on your platform port.
131  */
132 char *
lwip_strnstr(const char * buffer,const char * token,size_t n)133 lwip_strnstr(const char *buffer, const char *token, size_t n)
134 {
135   const char *p;
136   if (buffer == NULL || token == NULL) {
137     return NULL;
138   }
139   size_t tokenlen = strlen(token);
140   if (tokenlen == 0) {
141     return LWIP_CONST_CAST(char *, buffer);
142   }
143   for (p = buffer; *p && (p + tokenlen <= buffer + n); p++) {
144     if ((*p == *token) && (strncmp(p, token, tokenlen) == 0)) {
145       return LWIP_CONST_CAST(char *, p);
146     }
147   }
148   return NULL;
149 }
150 #endif
151 
152 #ifndef lwip_stricmp
153 /**
154  * @ingroup sys_nonstandard
155  * lwIP default implementation for stricmp() non-standard function.
156  * This can be \#defined to stricmp() depending on your platform port.
157  */
158 int
lwip_stricmp(const char * str1,const char * str2)159 lwip_stricmp(const char *str1, const char *str2)
160 {
161   char c1, c2;
162 
163   do {
164     c1 = *str1++;
165     c2 = *str2++;
166     if (c1 != c2) {
167       char c1_upc = c1 | 0x20;
168       if ((c1_upc >= 'a') && (c1_upc <= 'z')) {
169         /* characters are not equal an one is in the alphabet range:
170         downcase both chars and check again */
171         char c2_upc = c2 | 0x20;
172         if (c1_upc != c2_upc) {
173           /* still not equal */
174           /* don't care for < or > */
175           return 1;
176         }
177       } else {
178         /* characters are not equal but none is in the alphabet range */
179         return 1;
180       }
181     }
182   } while (c1 != 0);
183   return 0;
184 }
185 #endif
186 
187 #ifndef lwip_strnicmp
188 /**
189  * @ingroup sys_nonstandard
190  * lwIP default implementation for strnicmp() non-standard function.
191  * This can be \#defined to strnicmp() depending on your platform port.
192  */
193 int
lwip_strnicmp(const char * str1,const char * str2,size_t len)194 lwip_strnicmp(const char *str1, const char *str2, size_t len)
195 {
196   char c1, c2;
197 
198   do {
199     c1 = *str1++;
200     c2 = *str2++;
201     if (c1 != c2) {
202       char c1_upc = c1 | 0x20;
203       if ((c1_upc >= 'a') && (c1_upc <= 'z')) {
204         /* characters are not equal an one is in the alphabet range:
205         downcase both chars and check again */
206         char c2_upc = c2 | 0x20;
207         if (c1_upc != c2_upc) {
208           /* still not equal */
209           /* don't care for < or > */
210           return 1;
211         }
212       } else {
213         /* characters are not equal but none is in the alphabet range */
214         return 1;
215       }
216     }
217     len--;
218   } while ((len != 0) && (c1 != 0));
219   return 0;
220 }
221 #endif
222 
223 #ifndef lwip_itoa
224 /**
225  * @ingroup sys_nonstandard
226  * lwIP default implementation for itoa() non-standard function.
227  * This can be \#defined to itoa() or snprintf(result, bufsize, "%d", number) depending on your platform port.
228  */
229 void
lwip_itoa(char * result,size_t bufsize,int number)230 lwip_itoa(char *result, size_t bufsize, int number)
231 {
232   char *res = result;
233   char *tmp = result + bufsize - 1;
234   int n = (number >= 0) ? number : -number;
235 
236   /* handle invalid bufsize */
237   if (bufsize < 2) {
238     if (bufsize == 1) {
239       *result = 0;
240     }
241     return;
242   }
243 
244   /* First, add sign */
245   if (number < 0) {
246     *res++ = '-';
247   }
248   /* Then create the string from the end and stop if buffer full,
249      and ensure output string is zero terminated */
250   *tmp = 0;
251   while ((n != 0) && (tmp > res)) {
252     char val = (char)('0' + (n % 10));
253     tmp--;
254     *tmp = val;
255     n = n / 10;
256   }
257   if (n) {
258     /* buffer is too small */
259     *result = 0;
260     return;
261   }
262   if (*tmp == 0) {
263     /* Nothing added? */
264     *res++ = '0';
265     *res++ = 0;
266     return;
267   }
268   /* move from temporary buffer to output buffer (sign is not moved) */
269   if (memmove_s(res, (size_t)((bufsize - (size_t)(res - result))), tmp, (size_t)((result + bufsize) - tmp)) != 0) {
270     LWIP_PLATFORM_PRINT("lwip_itoa: memmove_s failed!\n");
271   }
272 }
273 #endif
274