eqemu-server/common/StringUtil.cpp

82 lines
2.3 KiB
C++

/*
* 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);
}
}