terminal_color.h

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#ifndef __TRMCLR_H__
#define __TRMCLR_H__

// Copyright (c) 2016 Camille Brugel
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgement in the product documentation would be
//    appreciated but is not required.
// 2. Altered source versions must be plainly marked as such, and must not be
//    misrepresented as being the original software.
// 3. This notice may not be removed or altered from any source distribution.

#include <cstdint>
#include <limits>
#include <ostream>
#include <sstream>
#include <string>

// ## Example

// ```c++
// #include "trmclr.hpp"
// #include <iostream>

// int main()
// {
//     trmclr::Style fancyStyle(trmclr::Background::LIGHT_BLUE    |
//                              trmclr::Foreground::WHITE         |
//                              trmclr::Attribute::UNDERLINED     |
//                              trmclr::Attribute::BOLD);

//     trmclr::Style basicStyle(trmclr::Attribute::DEFAULT);

//     std::cout << fancyStyle << "Hello "
//               << basicStyle << "World!\n";

//     return 0;
// }

// /*
// Note you can also do things like:
// auto bold = [](trmclr::Style style) { return trmclr::Style(style | trmclr::Attribute::BOLD); };
// */
// `

namespace trmclr {

  struct Style
  {
    Style(uint32_t value) : _value(value) {}

    operator uint32_t() const { return _value; }

    uint32_t _value;
  };

  enum StyleTypes { FOREGROUND, ATTRIBUTE, BACKGROUND, N_STYLE_TYPES };

  static const uint32_t STYLE_SHIFT = std::numeric_limits<uint32_t>::digits / N_STYLE_TYPES;

  struct Attribute
  {
    static const uint32_t SHIFT = STYLE_SHIFT * ATTRIBUTE;

    enum {
      DEFAULT    = 0x01 << SHIFT,
      BOLD       = 0x02 << SHIFT,
      DIM        = 0x04 << SHIFT,
      UNDERLINED = 0x08 << SHIFT,
      BLINK      = 0x10 << SHIFT,
      REVERSE    = 0x20 << SHIFT,
      HIDDEN     = 0x40 << SHIFT
    };
  };

  struct Foreground
  {
    static const uint32_t SHIFT = STYLE_SHIFT * FOREGROUND;

    enum {
      BLACK         = 30 << SHIFT,
      RED           = 31 << SHIFT,
      GREEN         = 32 << SHIFT,
      YELLOW        = 33 << SHIFT,
      BLUE          = 34 << SHIFT,
      MAGENTA       = 35 << SHIFT,
      CYAN          = 36 << SHIFT,
      LIGHT_GRAY    = 37 << SHIFT,
      DEFAULT       = 39 << SHIFT,
      DARK_GRAY     = 90 << SHIFT,
      LIGHT_RED     = 91 << SHIFT,
      LIGHT_GREEN   = 92 << SHIFT,
      LIGHT_YELLOW  = 93 << SHIFT,
      LIGHT_BLUE    = 94 << SHIFT,
      LIGHT_MAGENTA = 95 << SHIFT,
      LIGHT_CYAN    = 96 << SHIFT,
      WHITE         = 97 << SHIFT
    };
  };

  struct Background
  {
    static const uint32_t SHIFT = STYLE_SHIFT * BACKGROUND;

    enum {
      BLACK         = 40 << SHIFT,
      RED           = 41 << SHIFT,
      GREEN         = 42 << SHIFT,
      YELLOW        = 43 << SHIFT,
      BLUE          = 44 << SHIFT,
      MAGENTA       = 45 << SHIFT,
      CYAN          = 46 << SHIFT,
      LIGHT_GRAY    = 47 << SHIFT,
      DEFAULT       = 49 << SHIFT,
      DARK_GRAY     = 100 << SHIFT,
      LIGHT_RED     = 101 << SHIFT,
      LIGHT_GREEN   = 102 << SHIFT,
      LIGHT_YELLOW  = 103 << SHIFT,
      LIGHT_BLUE    = 104 << SHIFT,
      LIGHT_MAGENTA = 105 << SHIFT,
      LIGHT_CYAN    = 106 << SHIFT,
      WHITE         = 107 << SHIFT
    };
  };

  static Style black(trmclr::Foreground::BLACK);
  static Style red(trmclr::Foreground::RED);
  static Style green(trmclr::Foreground::GREEN);
  static Style yellow(trmclr::Foreground::YELLOW);
  static Style blue(trmclr::Foreground::BLUE);
  static Style magenta(trmclr::Foreground::MAGENTA);
  static Style cyan(trmclr::Foreground::CYAN);
  static Style normal(trmclr::Attribute::DEFAULT);

  inline std::ostream &operator<<(std::ostream &os, const Style &style)
  {
    const uint32_t base    = 1 << STYLE_SHIFT;
    uint32_t       encoded = style / base;
    uint32_t       decoded = style % base;

    os << "\x1B[" << (decoded ? decoded : Foreground::DEFAULT >> Foreground::SHIFT);

    decoded = encoded % base;

    for (uint32_t i = 0; decoded != 0; decoded >>= 1, i++) {
      if (decoded & 1) {
        os << ";" << i;
      }
    }

    encoded = encoded / base;
    decoded = encoded % base;

    os << ";" << (decoded ? decoded : Background::DEFAULT >> Background::SHIFT) << "m";

    return os;
  }

} // namespace trmclr
#endif // end __TRMCLR_H__