Format.h

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#pragma once
 
#if __cplusplus >= 202002L
// C++20 or newer is supported
#include <format>
#else
 
#include "Str.h"
namespace std {
 
class Format {
 public:
  template <typename... Args>
  Format(const char* fmt, Args... args) {
    parse(fmt, args...);
  }
 
  const char* c_str() { return buffer_.c_str(); }
 
  operator const char*() { return buffer_.c_str(); }
 
 private:
  audio_tools::Str buffer_;
 
  // Base case: process remaining format string when arguments run out
  void parse(const char* fmt) {
    while (*fmt != '\0') {
      // Check for escaped '{{' or '}}'
      if (*fmt == '{' && *(fmt + 1) == '{') {
        buffer_ += '{';
        fmt += 2;
        continue;
      }
      if (*fmt == '}' && *(fmt + 1) == '}') {
        buffer_ += '}';
        fmt += 2;
        continue;
      }
      buffer_ += *fmt++;
    }
  }
 
  // Recursive variadic template worker
  template <typename T, typename... Args>
  void parse(const char* fmt, T head_value, Args... tail_args) {
    while (*fmt != '\0') {
      // Check for '{}' placeholder
      if (*fmt == '{' && *(fmt + 1) == '}') {
        buffer_ += head_value;         // Append parameter
        parse(fmt + 2, tail_args...);  // Recurse onto remaining arguments
        return;
      }
      // Check for escaped '{{' or '}}'
      if (*fmt == '{' && *(fmt + 1) == '{') {
        buffer_ += '{';
        fmt += 2;
        continue;
      }
      if (*fmt == '}' && *(fmt + 1) == '}') {
        buffer_ += '}';
        fmt += 2;
        continue;
      }
 
      buffer_ += *fmt++;
    }
  }
};
 
}  // namespace std
#endif