Console Progress bar

ProgressBar.h

// ProgressBar.h
#pragma once

#include <iostream>
#include <fstream>
#include <cstdint>
#include <cassert>
#include <cmath>
#include <chrono>
#include <thread>

constexpr char ASCII_START_CH = (char)204;
constexpr char ASCII_MIDDLE_CH = (char)205;
constexpr char ASCII_END_CH = (char)185;

constexpr char ASCII_LOWDENSITY_CH = (char)176;
constexpr char ASCII_SOLID_CH = (char)219;

/// <summary>
/// 
/// </summary>
/// <param name="stream&">stream to write to</param>
/// <param name="width"></param>
/// <param name="fillto"></param>
static std::ostream& DrawBar(std::ostream &stream,
      uint32_t const width,
      uint32_t const fillto
   )
{
   uint32_t startlen = 0, endlen = 0;
   uint32_t middlelen = 0, index = 0;

   assert(width >= fillto);
   if (fillto <= 0) startlen = 1;
   if (fillto < width) endlen = width;
   if (width > 2) middlelen = width -1;

   for (; index < startlen; index++) 
      stream << ASCII_START_CH;
   for (; index < fillto; index++) 
      stream << ASCII_SOLID_CH;
   for (; index < middlelen; index++) 
      stream << ASCII_MIDDLE_CH;
   for (; index < endlen; index++) 
      stream << ASCII_END_CH;
   return stream;
}

/// <summary>
/// A progress bar for test mode console apps
/// </summary>
class ProgressBar {
private:
   char start_char, middle_char, end_char, fill_char;
   uint32_t bar_width;
   std::string message;

   std::ostream& PaintBar(std::ostream& stream, float percentage) {
      uint32_t startlen = 0, endlen = 0;
      uint32_t middlelen = 0, index = 0;
      uint32_t fillto = (uint32_t)std::ceil(percentage * bar_width);

      assert(bar_width >= fillto);
      if (fillto <= 0) startlen = 1;
      if (fillto < bar_width) endlen = bar_width;
      if (bar_width > 2) middlelen = bar_width - 1;

      for (; index < startlen; index++)
         stream << start_char;
      for (; index < fillto; index++)
         stream << fill_char;
      for (; index < middlelen; index++)
         stream << middle_char;
      for (; index < endlen; index++)
         stream << end_char;
      stream << " " << message << "\r";
      return stream;
   }
   uint32_t startlen = 0, endlen = 0;
   uint32_t middlelen = 0, index = 0;

   void _constr(uint32_t width) {
      _constr(width, 0.0f, "");
   }

   void _constr(uint32_t width,
      float start_percent,
      std::string const pre_message)
   {
      _constr(width, start_percent, pre_message);
   }

   void _constr(uint32_t width,
      float start_percent,
      std::string const pre_message,
      char start,
      char end,
      char middle,
      char fill
   ) {
      bar_width = width;
      message = pre_message;
      start_char = start;
      end_char = end;
      middle_char = middle;
      fill_char = fill;
      PaintBar(std::cout, 0.0f);
   }


public:
   ProgressBar(uint32_t width) {
      _constr(width);
   }

   ProgressBar(uint32_t width, float start_percent, std::string const pre_message) { 
      _constr(width, start_percent, pre_message, ASCII_START_CH, ASCII_END_CH, ASCII_MIDDLE_CH, ASCII_SOLID_CH);
   }

   ProgressBar(
      uint32_t width,
      float start_percent,
      std::string const pre_message,
      char start,
      char end,
      char middle,
      char fill
   ) {
      _constr(width, start_percent, pre_message, start, end, middle, fill);
   }

   std::ostream& UpdateBar(std::ostream& stream, float percentage) {
      return PaintBar(stream, percentage);
   }

   void UpdateMessage(std::string const new_message) { message = new_message; }
};

// example usage

int main() {
   {
      ProgressBar bar = ProgressBar(50, 0.0f, "");
      for (uint16_t full = 0; full <= 50; full++) {
         float percent = (float)(full / (float)50);
         std::string msg = std::to_string((uint32_t)(percent * 100)) + "%";
         bar.UpdateMessage(msg);
         bar.UpdateBar(std::cout, percent);
         std::this_thread::sleep_for(std::chrono::milliseconds(100));
      }
      std::cout << std::endl;
   } {
      ProgressBar bar = ProgressBar(80, 0.0f, "", ASCII_LOWDENSITY_CH, ASCII_LOWDENSITY_CH, ASCII_LOWDENSITY_CH, ASCII_SOLID_CH);
      for (uint16_t full = 0; full <= 50; full++) {
         float percent = (float)(full / (float)50);
         std::string msg = std::to_string((uint32_t)(percent * 100)) + "%";
         bar.UpdateMessage(msg);
         bar.UpdateBar(std::cout, percent);
         std::this_thread::sleep_for(std::chrono::milliseconds(100));
      }
   }
   return 0;
}