Merge branch 'jk/perf-no-dups'
[git/git.git] / compat / inet_ntop.c
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1/*
2 * Copyright (c) 1996-1999 by Internet Software Consortium.
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
15 * SOFTWARE.
16 */
17
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18#include "../git-compat-util.h"
19
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20#ifndef NS_INADDRSZ
21#define NS_INADDRSZ 4
22#endif
23#ifndef NS_IN6ADDRSZ
24#define NS_IN6ADDRSZ 16
25#endif
26#ifndef NS_INT16SZ
27#define NS_INT16SZ 2
28#endif
29
30/*
31 * WARNING: Don't even consider trying to compile this on a system where
32 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
33 */
34
35/* const char *
36 * inet_ntop4(src, dst, size)
37 * format an IPv4 address
38 * return:
39 * `dst' (as a const)
40 * notes:
41 * (1) uses no statics
42 * (2) takes a u_char* not an in_addr as input
43 * author:
44 * Paul Vixie, 1996.
45 */
46static const char *
bb34c5aa 47inet_ntop4(const u_char *src, char *dst, size_t size)
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48{
49 static const char fmt[] = "%u.%u.%u.%u";
50 char tmp[sizeof "255.255.255.255"];
51 int nprinted;
52
53 nprinted = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
54 if (nprinted < 0)
55 return (NULL); /* we assume "errno" was set by "snprintf()" */
db85a8a9 56 if ((size_t)nprinted >= size) {
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57 errno = ENOSPC;
58 return (NULL);
59 }
db85a8a9 60 strlcpy(dst, tmp, size);
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61 return (dst);
62}
63
64#ifndef NO_IPV6
65/* const char *
66 * inet_ntop6(src, dst, size)
67 * convert IPv6 binary address into presentation (printable) format
68 * author:
69 * Paul Vixie, 1996.
70 */
71static const char *
bb34c5aa 72inet_ntop6(const u_char *src, char *dst, size_t size)
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73{
74 /*
75 * Note that int32_t and int16_t need only be "at least" large enough
76 * to contain a value of the specified size. On some systems, like
77 * Crays, there is no such thing as an integer variable with 16 bits.
78 * Keep this in mind if you think this function should have been coded
79 * to use pointer overlays. All the world's not a VAX.
80 */
81 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
82 struct { int base, len; } best, cur;
1d182bd5 83 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
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84 int i;
85
86 /*
87 * Preprocess:
88 * Copy the input (bytewise) array into a wordwise array.
89 * Find the longest run of 0x00's in src[] for :: shorthanding.
90 */
91 memset(words, '\0', sizeof words);
92 for (i = 0; i < NS_IN6ADDRSZ; i++)
93 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
94 best.base = -1;
185528a8 95 best.len = 0;
6ba68ab2 96 cur.base = -1;
185528a8 97 cur.len = 0;
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98 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
99 if (words[i] == 0) {
100 if (cur.base == -1)
101 cur.base = i, cur.len = 1;
102 else
103 cur.len++;
104 } else {
105 if (cur.base != -1) {
106 if (best.base == -1 || cur.len > best.len)
107 best = cur;
108 cur.base = -1;
109 }
110 }
111 }
112 if (cur.base != -1) {
113 if (best.base == -1 || cur.len > best.len)
114 best = cur;
115 }
116 if (best.base != -1 && best.len < 2)
117 best.base = -1;
118
119 /*
120 * Format the result.
121 */
122 tp = tmp;
123 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
124 /* Are we inside the best run of 0x00's? */
125 if (best.base != -1 && i >= best.base &&
126 i < (best.base + best.len)) {
127 if (i == best.base)
128 *tp++ = ':';
129 continue;
130 }
131 /* Are we following an initial run of 0x00s or any real hex? */
132 if (i != 0)
133 *tp++ = ':';
134 /* Is this address an encapsulated IPv4? */
135 if (i == 6 && best.base == 0 &&
136 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
137 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
138 return (NULL);
139 tp += strlen(tp);
140 break;
141 }
142 tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
143 }
144 /* Was it a trailing run of 0x00's? */
145 if (best.base != -1 && (best.base + best.len) ==
146 (NS_IN6ADDRSZ / NS_INT16SZ))
147 *tp++ = ':';
148 *tp++ = '\0';
149
150 /*
151 * Check for overflow, copy, and we're done.
152 */
153 if ((size_t)(tp - tmp) > size) {
154 errno = ENOSPC;
155 return (NULL);
156 }
db85a8a9 157 strlcpy(dst, tmp, size);
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158 return (dst);
159}
160#endif
161
162/* char *
163 * inet_ntop(af, src, dst, size)
164 * convert a network format address to presentation format.
165 * return:
166 * pointer to presentation format address (`dst'), or NULL (see errno).
167 * author:
168 * Paul Vixie, 1996.
169 */
170const char *
bb34c5aa 171inet_ntop(int af, const void *src, char *dst, size_t size)
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172{
173 switch (af) {
174 case AF_INET:
175 return (inet_ntop4(src, dst, size));
176#ifndef NO_IPV6
177 case AF_INET6:
178 return (inet_ntop6(src, dst, size));
179#endif
180 default:
181 errno = EAFNOSUPPORT;
182 return (NULL);
183 }
184 /* NOTREACHED */
185}