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Paddle/paddle/fluid/string/printf.h

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// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
//
// 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.
// Compared with std::stringstream, there are primary purpose of
// string::Printf:
//
// 1. Type-safe printing, with why and how explained in
// http://www.drdobbs.com/stringprintf-a-typesafe-printf-family-fo/184401999.
// Implementation includes
//
// https://github.com/c42f/tinyformat
// boost::format
// std::stringstream
//
// std::stringstream is not convenient enough in many cases. For example:
//
// std::cout << std::setprecision(2) << std::fixed << 1.23456 << "\n";
//
// boost::format is the most convenient one. We can have
//
// std::cout << format("%2% %1%") % 36 % 77;
//
// or
//
// format fmter("%2% %1%");
// fmter % 36; fmter % 77;
// std::cout << fmter.c_str();
//
// But the overloading of % might be overkilling and it would be
// more efficient if it can write to std::cout directly.
//
// tinyformat has an interface compatible with the C-printf style,
// and it can writes to a stream or returns a std::string:
//
// std::cout << tfm::printf(
// "%s, %s %d, %.2d:%.2d\n",
// weekday, month, day, hour, min);
//
// or
//
// tfm::format(std::cout,
// "%s, %s %d, %.2d:%.2d\n",
// weekday, month, day, hour, min);
//
// 2. High-performance -- most printed strings are not too long and
// doens't need dynamic memory allocation. Many StringPrintf
// implementations doesn't enforce type-safe, but are
// high-performance, including
//
// https://developers.google.com/optimization/reference/base/stringprintf/
// https://github.com/adobe/chromium/blob/master/base/stringprintf.h
// https://github.com/google/protobuf/blob/master/src/google/protobuf/stubs/stringprintf.h
//
// According to
// https://github.com/c42f/tinyformat#compile-time-and-code-bloat,
// boost::format runs too slow and results in large executable binary
// files. So here we port tinyformat.
#pragma once
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include "tinyformat/tinyformat.h" // https://github.com/c42f/tinyformat
namespace paddle {
namespace string {
template <typename... Args>
void Fprintf(std::ostream& out, const char* fmt, const Args&... args) {
tinyformat::vformat(out, fmt, tinyformat::makeFormatList(args...));
}
inline std::string Sprintf() { return ""; }
template <typename... Args>
std::string Sprintf(const Args&... args) {
std::ostringstream oss;
Fprintf(oss, "%s", args...);
return oss.str();
}
template <typename... Args>
std::string Sprintf(const char* fmt, const Args&... args) {
std::ostringstream oss;
Fprintf(oss, fmt, args...);
return oss.str();
}
template <typename... Args>
void Printf(const char* fmt, const Args&... args) {
Fprintf(std::cout, fmt, args...);
}
inline std::string HumanReadableSize(double f_size) {
size_t i = 0;
double orig = f_size;
const std::vector<std::string> units(
{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"});
while (f_size >= 1024) {
f_size /= 1024;
i++;
}
if (i >= units.size()) {
return Sprintf("%fB", orig);
}
return Sprintf("%f%s", f_size, units[i]);
}
} // namespace string
} // namespace paddle