1 /*
2 Copyright (c) 1990 Regents of the University of California.
3 All rights reserved.
4 */
5 /*
6 FUNCTION
7 <<mblen>>---minimal multibyte length function
8
9 INDEX
10 mblen
11
12 SYNOPSIS
13 #include <stdlib.h>
14 int mblen(const char *<[s]>, size_t <[n]>);
15
16 DESCRIPTION
17 When _MB_CAPABLE is not defined, this is a minimal ANSI-conforming
18 implementation of <<mblen>>. In this case, the
19 only ``multi-byte character sequences'' recognized are single bytes,
20 and thus <<1>> is returned unless <[s]> is the null pointer or
21 has a length of 0 or is the empty string.
22
23 When _MB_CAPABLE is defined, this routine calls <<__MBTOWC>> to perform
24 the conversion, passing a state variable to allow state dependent
25 decoding. The result is based on the locale setting which may
26 be restricted to a defined set of locales.
27
28 RETURNS
29 This implementation of <<mblen>> returns <<0>> if
30 <[s]> is <<NULL>> or the empty string; it returns <<1>> if not _MB_CAPABLE or
31 the character is a single-byte character; it returns <<-1>>
32 if the multi-byte character is invalid; otherwise it returns
33 the number of bytes in the multibyte character.
34
35 PORTABILITY
36 <<mblen>> is required in the ANSI C standard. However, the precise
37 effects vary with the locale.
38
39 <<mblen>> requires no supporting OS subroutines.
40 */
41
42 #include <stdlib.h>
43 #include <wchar.h>
44 #include "local.h"
45
46 int
mblen(const char * s,size_t n)47 mblen (const char *s,
48 size_t n)
49 {
50 #ifdef _MB_CAPABLE
51 int retval = 0;
52 static NEWLIB_THREAD_LOCAL _mbstate_t _mblen_state;
53
54 retval = __MBTOWC (NULL, s, n, &_mblen_state);
55 if (retval < 0)
56 {
57 _mblen_state.__count = 0;
58 return -1;
59 }
60 else
61 return retval;
62
63 #else /* not _MB_CAPABLE */
64 if (s == NULL || *s == '\0')
65 return 0;
66 if (n == 0)
67 return -1;
68 return 1;
69 #endif /* not _MB_CAPABLE */
70 }
71
