Fixes #663: added safe snprintf code by Wolf-Dieter

git-svn-id: https://svn.code.sf.net/p/speed-dreams/code/trunk@5306 30fe4595-0a0c-4342-8851-515496e4dcbd

Former-commit-id: 6f2b0634fbb9a2e5a113a997e6fdbee48ce68aa4
Former-commit-id: 1b8ecdf3aa769c301a46cc72e19f092926f5d366

src/libs/portability/portability.cpp

@@ -63,10 +63,37 @@ char *strtok_r(char *str, const char *delim, char **nextp)
 	if (*str)
 		*str++ = '\0';
 	*nextp = str;
-	
+
 	return ret;
 }
 
 #endif // HAVE_STRTOK_R
 
 
+// Ticket #663 - MSVC implementation of snprintf is not safe
+// We provide our own version of the function,
+// that ensures 0 ending for the string.
+//
+// See http://msdn.microsoft.com/en-us/library/d3xd30zz(v=vs.80).aspx
+//
+// "Each of these functions takes a pointer to an argument list,
+// then formats and writes up to count characters of the given data
+// to the memory pointed to by buffer and appends a terminating null.
+// If count is _TRUNCATE, then these functions write as much of the
+// string as will fit in buffer while leaving room for a terminating
+// null. If the entire string (with terminating null) fits in buffer,
+// then these functions return the number of characters written
+// (not including the terminating null); otherwise, these functions
+// return -1 to indicate that truncation occurred."
+#ifdef _MSC_VER
+int SD_snprintf(char *str, size_t size, const char *format, ...)
+{
+	va_list vaArgs;
+	va_start(vaArgs, format);
+	int len = _vsnprintf_s(str, size, _TRUNCATE, format, vaArgs);
+	va_end(vaArgs);
+	if (size > 0)
+		str[size - 1] = 0;
+	return len;
+}
+#endif // _MSC_VER

src/libs/portability/portability.h

@@ -98,7 +98,12 @@ PORTABILITY_API char *strtok_r(char *str, const char *delim, char **nextp);
 
 #define isnan _isnan
 
-#define snprintf _snprintf
+// Ticket #663 - MSVC implementation of snprintf is not safe
+// We provide our own version of the function,
+// that ensures 0 ending for the string.
+#include <cstdarg>
+#include <cstdio>
+#define snprintf SD_snprintf
 
 #define access _access