Added StringUtil h/cpp which contains StringFormat

common/StringUtil.cpp

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed 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.
+ */
+
+#include "StringUtil.h"
+#include <string>
+#include <cstdarg>
+#include <stdexcept>
+
+#ifdef _WINDOWS
+	#include <windows.h>
+
+	#define snprintf	_snprintf
+	#define strncasecmp	_strnicmp
+	#define strcasecmp  _stricmp
+#else
+	#include <stdlib.h>
+#endif
+
+
+// original source: 
+// https://github.com/facebook/folly/blob/master/folly/String.cpp
+//
+void StringFormat(std::string& output, const char* format, ...) 
+{
+	va_list args;
+	// Tru to the space at the end of output for our output buffer.
+	// Find out write point then inflate its size temporarily to its
+	// capacity; we will later shrink it to the size needed to represent
+	// the formatted string.  If this buffer isn't large enough, we do a
+	// resize and try again.
+
+	const auto write_point = output.size();
+	auto remaining = output.capacity() - write_point;
+	output.resize(output.capacity());
+
+	va_start(args, format);
+	int bytes_used = vsnprintf(&output[write_point], remaining, format,args);
+	va_end(args);
+	if (bytes_used < 0) {
+		
+		std::string errorMessage("Invalid format string; snprintf returned negative with format string: ");
+		errorMessage.append(format);
+		
+		throw std::runtime_error(errorMessage);
+	} 
+	else if ((unsigned int)bytes_used < remaining) {
+		// There was enough room, just shrink and return.
+		output.resize(write_point + bytes_used);
+	} 
+	else {
+		output.resize(write_point + bytes_used + 1);
+		remaining = bytes_used + 1;
+
+		va_start(args, format);
+		bytes_used = vsnprintf(&output[write_point], remaining, format, args);
+		va_end(args);
+		
+		if ((unsigned int)(bytes_used + 1) != remaining) {
+			
+			std::string errorMessage("vsnprint retry did not manage to work with format string: ");
+			errorMessage.append(format);
+		
+			throw std::runtime_error(errorMessage);
+		}
+		
+		output.resize(write_point + bytes_used);
+	}
+}

common/StringUtil.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed 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.
+ */
+#ifndef _STRINGUTIL_H_
+#define _STRINGUTIL_H_
+
+#include <string>
+
+void StringFormat(std::string& output, const char* format, ...);
+
+#endif