1/* Charset name normalization.
2 Copyright (C) 2001-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 2001.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <ctype.h>
21#include <locale.h>
22#include <stdbool.h>
23#include <string.h>
24#include <sys/stat.h>
25#include <stdlib.h>
26#include "gconv_int.h"
27
28
29/* An iconv encoding is in the form of a triplet, with parts separated by
30 a '/' character. The first part is the standard name, the second part is
31 the character set, and the third part is the error handler. If the first
32 part is sufficient to identify both the standard and the character set
33 then the second part can be empty e.g. UTF-8//. If the first part is not
34 sufficient to identify both the standard and the character set then the
35 second part is required e.g. ISO-10646/UTF8/. If neither the first or
36 second parts are provided e.g. //, then the current locale is used.
37 The actual values used in the first and second parts are not entirely
38 relevant to the implementation. The values themselves are used in a hash
39 table to lookup modules and so the naming convention of the first two parts
40 is somewhat arbitrary and only helps locate the entries in the cache.
41 The third part is the error handler and is comprised of a ',' or '/'
42 separated list of suffixes. Currently, we support "TRANSLIT" for
43 transliteration and "IGNORE" for ignoring conversion errors due to
44 unrecognized input characters. */
45#define GCONV_TRIPLE_SEPARATOR "/"
46#define GCONV_SUFFIX_SEPARATOR ","
47#define GCONV_TRANSLIT_SUFFIX "TRANSLIT"
48#define GCONV_IGNORE_ERRORS_SUFFIX "IGNORE"
49
50
51/* This function accepts the charset names of the source and destination of the
52 conversion and populates *conv_spec with an equivalent conversion
53 specification that may later be used by __gconv_open. The charset names
54 might contain options in the form of suffixes that alter the conversion,
55 e.g. "ISO-10646/UTF-8/TRANSLIT". It processes the charset names, ignoring
56 and truncating any suffix options in fromcode, and processing and truncating
57 any suffix options in tocode. Supported suffix options ("TRANSLIT" or
58 "IGNORE") when found in tocode lead to the corresponding flag in *conv_spec
59 to be set to true. Unrecognized suffix options are silently discarded. If
60 the function succeeds, it returns conv_spec back to the caller. It returns
61 NULL upon failure. */
62struct gconv_spec *
63__gconv_create_spec (struct gconv_spec *conv_spec, const char *fromcode,
64 const char *tocode);
65libc_hidden_proto (__gconv_create_spec)
66
67
68/* This function frees all heap memory allocated by __gconv_create_spec. */
69static void __attribute__ ((unused))
70gconv_destroy_spec (struct gconv_spec *conv_spec)
71{
72 free (conv_spec->fromcode);
73 free (conv_spec->tocode);
74 return;
75}
76
77
78/* This function copies in-order, characters from the source 's' that are
79 either alpha-numeric or one in one of these: "_-.,:/" - into the destination
80 'wp' while dropping all other characters. In the process, it converts all
81 alphabetical characters to upper case. It then appends up to two '/'
82 characters so that the total number of '/'es in the destination is 2. */
83static inline void __attribute__ ((unused, always_inline))
84strip (char *wp, const char *s)
85{
86 int slash_count = 0;
87
88 while (*s != '\0')
89 {
90 if (__isalnum_l (*s, _nl_C_locobj_ptr)
91 || *s == '_' || *s == '-' || *s == '.' || *s == ',' || *s == ':')
92 *wp++ = __toupper_l (*s, _nl_C_locobj_ptr);
93 else if (*s == '/')
94 {
95 if (++slash_count == 3)
96 break;
97 *wp++ = '/';
98 }
99 ++s;
100 }
101
102 while (slash_count++ < 2)
103 *wp++ = '/';
104
105 *wp = '\0';
106}
107
108
109static inline char * __attribute__ ((unused, always_inline))
110upstr (char *dst, const char *str)
111{
112 char *cp = dst;
113 while ((*cp++ = __toupper_l (*str++, _nl_C_locobj_ptr)) != '\0')
114 /* nothing */;
115 return dst;
116}
117