ceph/src/fmt/test/custom-formatter-test.cc

   1 // Formatting library for C++ - custom argument formatter tests
   2 //
   3 // Copyright (c) 2012 - present, Victor Zverovich
   4 // All rights reserved.
   5 //
   6 // For the license information refer to format.h.
   7
   8 #ifndef _CRT_SECURE_NO_WARNINGS
   9 #define _CRT_SECURE_NO_WARNINGS
  10 #endif
  11
  12 #include "fmt/format.h"
  13 #include "gtest-extra.h"
  14
  15 // MSVC 2013 is known to be broken.
  16 #if !FMT_MSC_VER || FMT_MSC_VER > 1800
  17
  18 // A custom argument formatter that doesn't print `-` for floating-point values
  19 // rounded to 0.
  20 class custom_arg_formatter
  21     : public fmt::arg_formatter<fmt::buffer_range<char>> {
  22  public:
  23   using range = fmt::buffer_range<char>;
  24   typedef fmt::arg_formatter<range> base;
  25
  26   custom_arg_formatter(fmt::format_context& ctx,
  27                        fmt::format_parse_context* parse_ctx,
  28                        fmt::format_specs* s = nullptr)
  29       : base(ctx, parse_ctx, s) {}
  30
  31   using base::operator();
  32
  33   iterator operator()(double value) {
  34     // Comparing a float to 0.0 is safe.
  35     if (round(value * pow(10, specs()->precision)) == 0.0) value = 0;
  36     return base::operator()(value);
  37   }
  38 };
  39
  40 std::string custom_vformat(fmt::string_view format_str, fmt::format_args args) {
  41   fmt::memory_buffer buffer;
  42   // Pass custom argument formatter as a template arg to vwrite.
  43   fmt::vformat_to<custom_arg_formatter>(buffer, format_str, args);
  44   return std::string(buffer.data(), buffer.size());
  45 }
  46
  47 template <typename... Args>
  48 std::string custom_format(const char* format_str, const Args&... args) {
  49   auto va = fmt::make_format_args(args...);
  50   return custom_vformat(format_str, va);
  51 }
  52
  53 TEST(CustomFormatterTest, Format) {
  54   EXPECT_EQ("0.00", custom_format("{:.2f}", -.00001));
  55 }
  56 #endif