fmt/test/custom-formatter-test.cc
2018-09-12 08:45:14 -07:00

53 lines
1.5 KiB
C++

// Formatting library for C++ - custom argument formatter tests
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.
#include "fmt/format.h"
#include "gtest-extra.h"
// MSVC 2013 is known to be broken.
#if !FMT_MSC_VER || FMT_MSC_VER > 1800
// A custom argument formatter that doesn't print `-` for floating-point values
// rounded to 0.
class custom_arg_formatter :
public fmt::arg_formatter<fmt::back_insert_range<fmt::internal::buffer>> {
public:
typedef fmt::back_insert_range<fmt::internal::buffer> range;
typedef fmt::arg_formatter<range> base;
custom_arg_formatter(
fmt::format_context &ctx, fmt::format_specs *s = FMT_NULL)
: base(ctx, s) {}
using base::operator();
iterator operator()(double value) {
// Comparing a float to 0.0 is safe
if (round(value * pow(10, spec()->precision())) == 0.0)
value = 0;
return base::operator()(value);
}
};
std::string custom_vformat(fmt::string_view format_str, fmt::format_args args) {
fmt::memory_buffer buffer;
// Pass custom argument formatter as a template arg to vwrite.
fmt::vformat_to<custom_arg_formatter>(buffer, format_str, args);
return std::string(buffer.data(), buffer.size());
}
template <typename... Args>
std::string custom_format(const char *format_str, const Args & ... args) {
auto va = fmt::make_format_args(args...);
return custom_vformat(format_str, va);
}
TEST(CustomFormatterTest, Format) {
EXPECT_EQ("0.00", custom_format("{:.2f}", -.00001));
}
#endif