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sortix--sortix/libc/wchar/wcsnrtombs.cpp
2014-11-24 17:41:26 +01:00

87 lines
2.7 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
This file is part of the Sortix C Library.
The Sortix C Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
The Sortix 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
wchar/wcsnrtombs.cpp
Convert a wide-character string to multibyte string.
*******************************************************************************/
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
extern "C"
size_t wcsnrtombs(char* restrict dst,
const wchar_t** restrict src_ptr,
size_t src_len,
size_t dst_len,
mbstate_t* restrict ps)
{
static mbstate_t static_ps;
if ( !ps )
ps = &static_ps;
assert(src_ptr && *src_ptr);
const wchar_t* src = *src_ptr;
// Continue to encode multibyte characters until we have filled the
// destination buffer or if we have exhausted the limit on input wide chars.
size_t dst_offset = 0;
size_t src_offset = 0;
while ( (!dst || dst_offset < dst_len) && src_offset < src_len )
{
mbstate_t ps_copy = *ps;
wchar_t wc = src[src_offset];
char mb[MB_CUR_MAX];
size_t amount = wcrtomb(mb, wc, ps);
// Stop in the event a decoding error occured.
if ( amount == (size_t) -1 )
return *src_ptr = src + src_offset, (size_t) -1;
// Stop decoding early in the event we encountered a partial character,
// or that we ran out of space in the destination buffer.
if ( amount == (size_t) -2 || (dst && dst_offset - dst_len < amount ) )
{
*ps = ps_copy;
break;
}
// Store the decoded multibyte character in the destination buffer.
if ( dst )
memcpy(dst + dst_offset, mb, amount);
// Stop decoding after decoding a null character and return a NULL
// source pointer to the caller, not including the null character in the
// number of characters stored in the destination buffer.
if ( wc == L'\0' )
{
src = NULL;
src_offset = 0;
break;
}
dst_offset += amount;
src_offset++;
}
return *src_ptr = src + src_offset, dst_offset;
}