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/*
Copyright (c) 1990 Regents of the University of California.
All rights reserved.
*/
/*
FUNCTION
<<wcstombs>>---minimal wide char string to multibyte string converter
INDEX
wcstombs
SYNOPSIS
#include <stdlib.h>
size_t wcstombs(char *restrict <[s]>, const wchar_t *restrict <[pwc]>, size_t <[n]>);
DESCRIPTION
When __MB_CAPABLE is not defined, this is a minimal ANSI-conforming
implementation of <<wcstombs>>. In this case,
all wide-characters are expected to represent single bytes and so
are converted simply by casting to char.
When __MB_CAPABLE is defined, this routine uses a state variable to
allow state dependent decoding. The result is based on the locale
setting which may be restricted to a defined set of locales.
RETURNS
This implementation of <<wcstombs>> returns <<0>> if
<[s]> is <<NULL>> or is the empty string;
it returns <<-1>> if __MB_CAPABLE and one of the
wide-char characters does not represent a valid multi-byte character;
otherwise it returns the minimum of: <<n>> or the
number of bytes that are transferred to <<s>>, not including the
nul terminator.
If the return value is -1, the state of the <<pwc>> string is
indeterminate. If the input has a length of 0, the output
string will be modified to contain a wchar_t nul terminator if
<<n>> > 0.
PORTABILITY
<<wcstombs>> is required in the ANSI C standard. However, the precise
effects vary with the locale.
<<wcstombs>> requires no supporting OS subroutines.
*/
#include <stdlib.h>
#include <wchar.h>
#include "local.h"
size_t
wcstombs(char * __restrict s, const wchar_t * __restrict pwcs, size_t n)
{
#ifdef __MB_CAPABLE
mbstate_t state;
state.__count = 0;
char *ptr = s;
size_t max = n;
char buff[8];
int i, bytes, num_to_copy;
if (s == NULL) {
size_t num_bytes = 0;
while (*pwcs != 0) {
bytes = __WCTOMB(buff, *pwcs++, &state);
if (bytes == -1)
return -1;
num_bytes += bytes;
}
return num_bytes;
} else {
while (n > 0) {
bytes = __WCTOMB(buff, *pwcs, &state);
if (bytes == -1)
return -1;
num_to_copy = (n > (size_t)bytes ? bytes : (int)n);
for (i = 0; i < num_to_copy; ++i)
*ptr++ = buff[i];
if (*pwcs == 0x00)
return ptr - s - (n >= (size_t)bytes);
++pwcs;
n -= num_to_copy;
}
return max;
}
#else /* not __MB_CAPABLE */
int count = 0;
if (n != 0) {
do {
if ((*s++ = (char)*pwcs++) == 0)
break;
count++;
} while (--n != 0);
}
return count;
#endif /* not __MB_CAPABLE */
}
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