/**************************************************************
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *************************************************************/

#define _SNPRINTF_DLLIMPORT __declspec( dllexport )

#include <stdarg.h>
#include <stdio.h>

#include <tchar.h>
#include <systools/win32/snprintf.h>

#if defined(_MSC_VER) && (_MSC_VER >= 1400)
#pragma warning(disable:4273)		// inconsistent dll linkage
#endif

#if (defined(_MSC_VER) && (_MSC_VER < 1300)) || (defined(__MINGW32_VERSION) && ((__MINGW32_MAJOR_VERSION < 3)||((__MINGW32_MAJOR_VERSION == 3)&&(__MINGW32_MINOR_VERSION < 18))))

/*	The non-debug versions of _vscprintf/_scprintf are just calls
	to _vsprintf/_sprintf with string buffer pointer set to NULL,
	requires MSVCRT version 7.0 */
#ifdef __MINGW32__
static int __cdecl _vsctprintf( const TCHAR *format, va_list ap )
#else
static int __cdecl _vsctprintf( const _TXCHAR *format, va_list ap )
#endif
{
	FILE	*fp = _tfopen( _T("NUL"), _T("wb") );

	if ( fp )
	{
		int	retval = _vftprintf( fp, format, ap );
		fclose( fp );

		return retval;
	}

	return -1;
}
#endif

/*	This function retrieves the pointer to the last character of a buffer.
	That is the pointer to the last character of the buffer that fits
	completely into that buffer or the position of the terminating zero.

	buffer	Pointer to a _TXCHAR buffer to be examined
	count	size of the buffer to be examined

	return	The pointer to the last character that fits into the buffer or
			NULL if count is zero or count is one and the first byte was a
			leading	DBCS character
*/

static _TCHAR *GetLastBufferChar( _TCHAR *buffer, size_t count )
{
	_TCHAR	*last = NULL;
	_TCHAR	*cur = buffer;

	while ( (size_t)(cur - buffer) < count )
	{
		last = cur;

		if ( !*last )
			break;

		cur = _tcsinc(last);
	}

	return last;
}

/* Implementation of snprintf following the ISO/IEC 9899:1999 (ISO C99) standard */

_SNPRINTF_DLLIMPORT int __cdecl vsntprintf( _TCHAR *buffer, size_t count, const _TCHAR *format, va_list list )
{
	int		retval;

	/*	First of all call the existing non POSIX standard function assuming
		the buffer size will be large enough */

	retval = _vsntprintf( buffer, count, format, list );

	if ( retval < 0 )
	{
		/*	If the buffer wasn't large enough ensure that the buffer will be
			zero terminated */

		_TCHAR	*last = GetLastBufferChar( buffer, count );
		if (last )
			*last = 0;

		/*	Retrieve the count of characters that would have been written
			if the buffer were large enough */

		retval = _vsctprintf( format, list );
	}
	else if ( (size_t)retval == count && count )
	{
		/*	If the buffer was large enough but not large enough for the trailing
			zero make the buffer zero terminated */

		_TCHAR	*last = GetLastBufferChar( buffer, count );
		if (last )
			*last = 0;
	}

	return retval;
}

/* Implementation of snprintf following the ISO/IEC 9899:1999 (ISO C99) standard */

_SNPRINTF_DLLIMPORT int __cdecl sntprintf( _TCHAR *buffer, size_t count, const _TCHAR *format, ... )
{
	va_list	list;
	int		retval;

	va_start( list, format );
	retval = vsntprintf( buffer, count, format, list );
	va_end( list );

	return retval;
}