sprintf replacement: introduce au_snprintf to support snprintf for v2013

and earier ( closes https://github.com/assimp/assimp/issues/743 )

code/StringUtils.h

@@ -0,0 +1,98 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2016, assimp team
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+#ifndef INCLUDED_AI_STRINGUTILS_H
+#define INCLUDED_AI_STRINGUTILS_H
+
+#include <cstdarg>
+#include <string.h>
+#include <stdio.h>
+
+namespace Assimp {
+
+///	@fn		ai_snprintf
+///	@brief	The portable version of the function snprintf ( C99 standard ), which works on visual studio compilers 2013 and earlier.
+///	@param	outBuf		The buffer to write in
+///	@param	size		The buffer size
+///	@param	format		The format string
+///	@param	ap			The additional arguments.
+///	@return	The number of written characters if the buffer size was big enough. If an encoding error occurs, a negative number is returned.
+#if defined(_MSC_VER) && _MSC_VER < 1900
+
+	inline int c99_ai_vsnprintf(char *outBuf, size_t size, const char *format, va_list ap) {
+		int count(-1);
+		if (0 != size) {
+			count = _vsnprintf_s(outBuf, size, _TRUNCATE, format, ap);
+		}
+		if (count == -1) {
+			count = _vscprintf(format, ap);
+		}
+
+		return count;
+	}
+
+	inline int ai_snprintf(char *s, size_t n, const char *fmt, ...) {
+		int count;
+		va_list ap;
+
+		va_start(ap, fmt);
+		count = c99_ai_vsnprintf(outBuf, size, fmt, ap);
+		va_end(ap);
+
+		return count;
+	}
+
+#else
+
+	inline int ai_snprintf(char *s, size_t n, const char *format, ...) {
+		int count;
+		va_list ap;
+		va_start(ap, format);
+		count = snprintf(s, n, format, ap);
+		va_end(ap);
+
+		return count;
+	}
+
+#endif
+
+} // Namespace Assimp
+
+#endif // INCLUDED_AI_STRINGUTILS_H
+