xref: /freebsd/contrib/libpcap/charconv.c (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
2 /*
3  * Copyright (c) 1993, 1994, 1995, 1996, 1997
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by the Computer Systems
17  *	Engineering Group at Lawrence Berkeley Laboratory.
18  * 4. Neither the name of the University nor of the Laboratory may be used
19  *    to endorse or promote products derived from this software without
20  *    specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifdef _WIN32
36 #include <stdio.h>
37 #include <errno.h>
38 
39 #include <pcap/pcap.h>	/* Needed for PCAP_ERRBUF_SIZE */
40 
41 #include "charconv.h"
42 
43 wchar_t *
44 cp_to_utf_16le(UINT codepage, const char *cp_string, DWORD flags)
45 {
46 	int utf16le_len;
47 	wchar_t *utf16le_string;
48 
49 	/*
50 	 * Map from the specified code page to UTF-16LE.
51 	 * First, find out how big a buffer we'll need.
52 	 */
53 	utf16le_len = MultiByteToWideChar(codepage, flags, cp_string, -1,
54 	    NULL, 0);
55 	if (utf16le_len == 0) {
56 		/*
57 		 * Error.  Fail with EINVAL.
58 		 */
59 		errno = EINVAL;
60 		return (NULL);
61 	}
62 
63 	/*
64 	 * Now attempt to allocate a buffer for that.
65 	 */
66 	utf16le_string = malloc(utf16le_len * sizeof (wchar_t));
67 	if (utf16le_string == NULL) {
68 		/*
69 		 * Not enough memory; assume errno has been
70 		 * set, and fail.
71 		 */
72 		return (NULL);
73 	}
74 
75 	/*
76 	 * Now convert.
77 	 */
78 	utf16le_len = MultiByteToWideChar(codepage, flags, cp_string, -1,
79 	    utf16le_string, utf16le_len);
80 	if (utf16le_len == 0) {
81 		/*
82 		 * Error.  Fail with EINVAL.
83 		 * XXX - should this ever happen, given that
84 		 * we already ran the string through
85 		 * MultiByteToWideChar() to find out how big
86 		 * a buffer we needed?
87 		 */
88 		free(utf16le_string);
89 		errno = EINVAL;
90 		return (NULL);
91 	}
92 	return (utf16le_string);
93 }
94 
95 char *
96 utf_16le_to_cp(UINT codepage, const wchar_t *utf16le_string)
97 {
98 	int cp_len;
99 	char *cp_string;
100 
101 	/*
102 	 * Map from UTF-16LE to the specified code page.
103 	 * First, find out how big a buffer we'll need.
104 	 * We convert composite characters to precomposed characters,
105 	 * as that's what Windows expects.
106 	 */
107 	cp_len = WideCharToMultiByte(codepage, WC_COMPOSITECHECK,
108 	    utf16le_string, -1, NULL, 0, NULL, NULL);
109 	if (cp_len == 0) {
110 		/*
111 		 * Error.  Fail with EINVAL.
112 		 */
113 		errno = EINVAL;
114 		return (NULL);
115 	}
116 
117 	/*
118 	 * Now attempt to allocate a buffer for that.
119 	 */
120 	cp_string = malloc(cp_len * sizeof (char));
121 	if (cp_string == NULL) {
122 		/*
123 		 * Not enough memory; assume errno has been
124 		 * set, and fail.
125 		 */
126 		return (NULL);
127 	}
128 
129 	/*
130 	 * Now convert.
131 	 */
132 	cp_len = WideCharToMultiByte(codepage, WC_COMPOSITECHECK,
133 	    utf16le_string, -1, cp_string, cp_len, NULL, NULL);
134 	if (cp_len == 0) {
135 		/*
136 		 * Error.  Fail with EINVAL.
137 		 * XXX - should this ever happen, given that
138 		 * we already ran the string through
139 		 * WideCharToMultiByte() to find out how big
140 		 * a buffer we needed?
141 		 */
142 		free(cp_string);
143 		errno = EINVAL;
144 		return (NULL);
145 	}
146 	return (cp_string);
147 }
148 
149 /*
150  * Convert an error message string from UTF-8 to the local code page, as
151  * best we can.
152  *
153  * The buffer is assumed to be PCAP_ERRBUF_SIZE bytes long; we truncate
154  * if it doesn't fit.
155  */
156 void
157 utf_8_to_acp_truncated(char *errbuf)
158 {
159 	wchar_t *utf_16_errbuf;
160 	int retval;
161 	DWORD err;
162 
163 	/*
164 	 * Do this by converting to UTF-16LE and then to the local
165 	 * code page.  That means we get to use Microsoft's
166 	 * conversion routines, rather than having to understand
167 	 * all the code pages ourselves, *and* that this routine
168 	 * can convert in place.
169 	 */
170 
171 	/*
172 	 * Map from UTF-8 to UTF-16LE.
173 	 * First, find out how big a buffer we'll need.
174 	 * Convert any invalid characters to REPLACEMENT CHARACTER.
175 	 */
176 	utf_16_errbuf = cp_to_utf_16le(CP_UTF8, errbuf, 0);
177 	if (utf_16_errbuf == NULL) {
178 		/*
179 		 * Error.  Give up.
180 		 */
181 		snprintf(errbuf, PCAP_ERRBUF_SIZE,
182 		    "Can't convert error string to the local code page");
183 		return;
184 	}
185 
186 	/*
187 	 * Now, convert that to the local code page.
188 	 * Use the current thread's code page.  For unconvertible
189 	 * characters, let it pick the "best fit" character.
190 	 *
191 	 * XXX - we'd like some way to do what utf_16le_to_utf_8_truncated()
192 	 * does if the buffer isn't big enough, but we don't want to have
193 	 * to handle all local code pages ourselves; doing so requires
194 	 * knowledge of all those code pages, including knowledge of how
195 	 * characters are formed in those code pages so that we can avoid
196 	 * cutting a multi-byte character into pieces.
197 	 *
198 	 * Converting to an un-truncated string using Windows APIs, and
199 	 * then copying to the buffer, still requires knowledge of how
200 	 * characters are formed in the target code page.
201 	 */
202 	retval = WideCharToMultiByte(CP_THREAD_ACP, 0, utf_16_errbuf, -1,
203 	    errbuf, PCAP_ERRBUF_SIZE, NULL, NULL);
204 	if (retval == 0) {
205 		err = GetLastError();
206 		free(utf_16_errbuf);
207 		if (err == ERROR_INSUFFICIENT_BUFFER)
208 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
209 			    "The error string, in the local code page, didn't fit in the buffer");
210 		else
211 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
212 			    "Can't convert error string to the local code page");
213 		return;
214 	}
215 	free(utf_16_errbuf);
216 }
217 #endif
218