xref: /haiku/src/system/libroot/posix/wchar/mbrtowc.cpp (revision 4a55cc230cf7566cadcbb23b1928eefff8aea9a2)
1 /*
2 ** Copyright 2011, Oliver Tappe, zooey@hirschkaefer.de. All rights reserved.
3 ** Distributed under the terms of the MIT License.
4 */
5 
6 #include <errno.h>
7 #include <string.h>
8 #include <wchar.h>
9 
10 #include <errno_private.h>
11 #include <LocaleBackend.h>
12 
13 
14 //#define TRACE_MBRTOWC
15 #ifdef TRACE_MBRTOWC
16 #	include <OS.h>
17 #	define TRACE(x) debug_printf x
18 #else
19 #	define TRACE(x) ;
20 #endif
21 
22 
23 using BPrivate::Libroot::GetCurrentLocaleBackend;
24 using BPrivate::Libroot::LocaleBackend;
25 
26 
27 extern "C" size_t
28 __mbrtowc(wchar_t* pwc, const char* s, size_t n, mbstate_t* ps)
29 {
30 	if (ps == NULL) {
31 		static mbstate_t internalMbState;
32 		ps = &internalMbState;
33 	}
34 
35 	if (s == NULL)
36 		return __mbrtowc(NULL, "", 1, ps);
37 
38 	LocaleBackend* backend = GetCurrentLocaleBackend();
39 
40 	if (backend == NULL) {
41 		if (*s == '\0') {
42 			memset(ps, 0, sizeof(mbstate_t));
43 
44 			if (pwc != NULL)
45 				*pwc = 0;
46 
47 			return 0;
48 		}
49 
50 		/*
51 		 * The POSIX locale is active. Since the POSIX locale only contains
52 		 * chars 0-127 and those ASCII chars are compatible with the UTF32
53 		 * values used in wint_t, we can just return the byte.
54 		 */
55 
56 		if (*s < 0) {
57 			// char is non-ASCII
58 			__set_errno(EILSEQ);
59 			return (size_t)-1;
60 		}
61 
62 		if (pwc != NULL)
63 			*pwc = *s;
64 
65 		return 1;
66 	}
67 
68 	size_t lengthUsed;
69 	status_t status = backend->MultibyteToWchar(pwc, s, n, ps, lengthUsed);
70 
71 	if (status == B_BAD_INDEX)
72 		return (size_t)-2;
73 
74 	if (status == B_BAD_DATA) {
75 		TRACE(("mbrtowc(): setting errno to EILSEQ\n"));
76 		__set_errno(EILSEQ);
77 		return (size_t)-1;
78 	}
79 
80 	if (status != B_OK) {
81 		TRACE(("mbrtowc(): setting errno to EINVAL (status: %lx)\n", status));
82 		__set_errno(EINVAL);
83 		return (size_t)-1;
84 	}
85 
86 	return lengthUsed;
87 }
88 
89 
90 B_DEFINE_WEAK_ALIAS(__mbrtowc, mbrtowc);
91