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/* 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
static mbstate_t internal;
size_t
mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
{
size_t used = 0;
if (ps == NULL)
ps = &internal;
if (s == NULL)
{
/* See first paragraph of description in 7.16.6.3.2. */
pwc = NULL;
s = "";
n = 1;
}
if (n > 0)
{
if (ps->count == 0)
{
unsigned char byte = (unsigned char) *s++;
++used;
/* We must look for a possible first byte of a UTF8 sequence. */
if (byte < 0x80)
{
/* One byte sequence. */
if (pwc != NULL)
*pwc = (wchar_t) byte;
return byte ? used : 0;
}
if ((byte & 0xc0) == 0x80 || (byte & 0xfe) == 0xfe)
{
/* Oh, oh. An encoding error. */
errno = EILSEQ;
return (size_t) -1;
}
if ((byte & 0xe0) == 0xc0)
{
/* We expect two bytes. */
ps->count = 1;
ps->value = byte & 0x1f;
}
else if ((byte & 0xf0) == 0xe0)
{
/* We expect three bytes. */
ps->count = 2;
ps->value = byte & 0x0f;
}
else if ((byte & 0xf8) == 0xf0)
{
/* We expect four bytes. */
ps->count = 3;
ps->value = byte & 0x07;
}
else if ((byte & 0xfc) == 0xf8)
{
/* We expect five bytes. */
ps->count = 4;
ps->value = byte & 0x03;
}
else
{
/* We expect six bytes. */
ps->count = 5;
ps->value = byte & 0x01;
}
}
/* We know we have to handle a multibyte character and there are
some more bytes to read. */
while (used < n)
{
/* The second to sixths byte must be of the form 10xxxxxx. */
unsigned char byte = (unsigned char) *s++;
++used;
if ((byte & 0xc0) != 0x80)
{
/* Oh, oh. An encoding error. */
errno = EILSEQ;
return (size_t) -1;
}
ps->value <<= 6;
ps->value |= byte & 0x3f;
if (--ps->count == 0)
{
/* The character is finished. */
if (pwc != NULL)
*pwc = (wchar_t) ps->value;
return ps->value ? used : 0;
}
}
}
return (size_t) -2;
}
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