reactos/sdk/lib/ucrt/stdio/fgetwc.cpp
2025-01-16 14:18:53 +02:00

137 lines
3.1 KiB
C++

//
// fgetwc.cpp
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// Functions that read the next wide character from a stream and return it. If
// the read causes the stream to reach EOF, WEOF is returned and the EOF bit is
// set on the stream.
//
#include <corecrt_internal_stdio.h>
extern "C" wint_t __cdecl _fgetwc_nolock(FILE* const public_stream)
{
__crt_stdio_stream const stream(public_stream);
// If the stream is backed by a real file and is open in a Unicode text mode,
// we need to read two bytes (note that we read two bytes for both UTF-8 and
// UTF-16 backed streams, since lowio translates UTF-8 to UTF-16 when we read.
if (!stream.is_string_backed() &&
_textmode_safe(_fileno(stream.public_stream())) != __crt_lowio_text_mode::ansi)
{
wchar_t wc;
// Compose the wide character by reading byte-by-byte from the stream:
char* const wc_first = reinterpret_cast<char*>(&wc);
char* const wc_last = wc_first + sizeof(wc);
for (char* it = wc_first; it != wc_last; ++it)
{
int const c = _getc_nolock(stream.public_stream());
if (c == EOF)
return WEOF;
*it = static_cast<char>(c);
}
return wc;
}
if (!stream.is_string_backed() &&
(_osfile_safe(_fileno(stream.public_stream())) & FTEXT))
{
int size = 1;
int ch;
char mbc[4];
wchar_t wch;
/* text (multi-byte) mode */
if ((ch = _getc_nolock(stream.public_stream())) == EOF)
return WEOF;
mbc[0] = static_cast<char>(ch);
if (isleadbyte(static_cast<unsigned char>(mbc[0])))
{
if ((ch = _getc_nolock(stream.public_stream())) == EOF)
{
ungetc(mbc[0], stream.public_stream());
return WEOF;
}
mbc[1] = static_cast<char>(ch);
size = 2;
}
if (mbtowc(&wch, mbc, size) == -1)
{
// Conversion failed! Set errno and return failure:
errno = EILSEQ;
return WEOF;
}
return wch;
}
// binary (Unicode) mode
if (stream->_cnt >= static_cast<int>(sizeof(wchar_t)))
{
stream->_cnt -= static_cast<int>(sizeof(wchar_t));
return *reinterpret_cast<wchar_t*&>(stream->_ptr)++;
}
else
{
return static_cast<wint_t>(__acrt_stdio_refill_and_read_wide_nolock(stream.public_stream()));
}
}
extern "C" wint_t __cdecl _getwc_nolock(FILE* const stream)
{
return _fgetwc_nolock(stream);
}
extern "C" wint_t __cdecl fgetwc(FILE* const stream)
{
_VALIDATE_RETURN(stream != nullptr, EINVAL, WEOF);
wint_t return_value = 0;
_lock_file(stream);
__try
{
return_value = _fgetwc_nolock(stream);
}
__finally
{
_unlock_file(stream);
}
__endtry
return return_value;
}
extern "C" wint_t __cdecl getwc(FILE* const stream)
{
return fgetwc(stream);
}
extern "C" wint_t __cdecl _fgetwchar()
{
return fgetwc(stdin);
}
extern "C" wint_t __cdecl getwchar()
{
return _fgetwchar();
}