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[glibc.git] / wcsmbs / wcsrtombs.c
blobb2c0c73778e985ed5e0f9ddeca3bd282d5351866
1 /* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
20 #include <errno.h>
21 #include <wchar.h>
23 #ifndef EILSEQ
24 #define EILSEQ EINVAL
25 #endif
28 static const wchar_t encoding_mask[] =
30 ~0x7ff, ~0xffff, ~0x1fffff, ~0x3ffffff
33 static const unsigned char encoding_byte[] =
35 0xc0, 0xe0, 0xf0, 0xf8, 0xfc
38 /* We don't need the state really because we don't have shift states
39 to maintain between calls to this function. */
40 static mbstate_t internal;
42 size_t
43 __wcsrtombs (dst, src, len, ps)
44 char *dst;
45 const wchar_t **src;
46 size_t len;
47 mbstate_t *ps;
49 size_t written = 0;
50 const wchar_t *run = *src;
52 if (ps == NULL)
53 ps = &internal;
55 if (dst == NULL)
56 /* The LEN parameter has to be ignored if we don't actually write
57 anything. */
58 len = ~0;
60 while (written < len)
62 wchar_t wc = *run++;
64 if (wc < 0 || wc > 0x7fffffff)
66 /* This is no correct ISO 10646 character. */
67 __set_errno (EILSEQ);
68 return (size_t) -1;
71 if (wc == L'\0')
73 /* Found the end. */
74 if (dst != NULL)
75 *dst = '\0';
76 *src = NULL;
77 return written;
79 else if (wc < 0x80)
81 /* It's an one byte sequence. */
82 if (dst != NULL)
83 *dst++ = (char) wc;
84 ++written;
86 else
88 size_t step;
90 for (step = 2; step < 6; ++step)
91 if ((wc & encoding_mask[step - 2]) == 0)
92 break;
94 if (written + step >= len)
95 /* Too long. */
96 break;
98 if (dst != NULL)
100 size_t cnt = step;
102 dst[0] = encoding_byte[cnt - 2];
104 --cnt;
107 dst[cnt] = 0x80 | (wc & 0x3f);
108 wc >>= 6;
110 while (--cnt > 0);
111 dst[0] |= wc;
113 dst += step;
116 written += step;
120 /* Store position of first unprocessed word. */
121 *src = run;
123 return written;
125 weak_alias (__wcsrtombs, wcsrtombs)