about summary refs log tree commit diff
path: root/wcsmbs/mbsnrtowcs.c
blob: 27906957e90b4c069c99637ded836a0f1db136a6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <wchar.h>

#ifndef EILSEQ
#define EILSEQ EINVAL
#endif


/* We don't need the state really because we don't have shift states
   to maintain between calls to this function.  */
static mbstate_t internal;

/* This is a non-standard function but it is very useful in the
   implementation of stdio because we have to deal with unterminated
   buffers.  At most NMC bytes will be converted.  */
size_t
__mbsnrtowcs (dst, src, nmc, len, ps)
     wchar_t *dst;
     const char **src;
     size_t nmc;
     size_t len;
     mbstate_t *ps;
{
  size_t written = 0;
  const char *run = *src;
  const char *last = run + nmc;

  if (ps == NULL)
    ps = &internal;

  if (dst == NULL)
    /* The LEN parameter has to be ignored if we don't actually write
       anything.  */
    len = ~0;

  /* Copy all words.  */
  while (written < len && run < last)
    {
      wchar_t value;
      size_t count;
      unsigned char byte = *run++;

      /* We expect a start of a new multibyte character.  */
      if (byte < 0x80)
	{
	  /* One byte sequence.  */
	  count = 0;
	  value = byte;
	}
      else if ((byte & 0xe0) == 0xc0)
	{
	  count = 1;
	  value = byte & 0x1f;
	}
      else if ((byte & 0xf0) == 0xe0)
	{
	  /* We expect three bytes.  */
	  count = 2;
	  value = byte & 0x0f;
	}
      else if ((byte & 0xf8) == 0xf0)
	{
	  /* We expect four bytes.  */
	  count = 3;
	  value = byte & 0x07;
	}
      else if ((byte & 0xfc) == 0xf8)
	{
	  /* We expect five bytes.  */
	  count = 4;
	  value = byte & 0x03;
	}
      else if ((byte & 0xfe) == 0xfc)
	{
	  /* We expect six bytes.  */
	  count = 5;
	  value = byte & 0x01;
	}
      else
	{
	  /* This is an illegal encoding.  */
	  errno = EILSEQ;
	  return (size_t) -1;
	}

      /* Read the possible remaining bytes.  */
      while (count-- > 0)
	{
	  byte = *run++;

	  if ((byte & 0xc0) != 0x80)
	    {
	      /* This is an illegal encoding.  */
	      errno = EILSEQ;
	      return (size_t) -1;
	    }

	  value <<= 6;
	  value |= byte & 0x3f;
	}

      /* Store value is required.  */
      if (dst != NULL)
	*dst++ = value;

      /* The whole sequence is read.  Check whether end of string is
	 reached.  */
      if (value == L'\0')
	{
	  /* Found the end of the string.  */
	  *src = NULL;
	  return written;
	}

      /* Increment counter of produced words.  */
      ++written;
    }

  /* Store address of next byte to process.  */
  *src = run;

  return written;
}
weak_alias (__mbsnrtowcs, mbsnrtowcs)