Dice.h

/*
 * Gamedev Framework (gf)
 * Copyright (C) 2016-2019 Julien Bernard
 *
 * 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 acknowledgment 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.
 */
#ifndef GF_DICE_H
#define GF_DICE_H

#include <cassert>
#include <climits>

#include "Portability.h"
#include "Random.h"
#include "StringRef.h"

namespace gf {
#ifndef DOXYGEN_SHOULD_SKIP_THIS
inline namespace v1 {
#endif

  class GF_API Dice {
  public:
    constexpr explicit Dice(int faces, int count = 1, int modifier = 0)
    : m_faces(faces)
    , m_count(count)
    , m_modifier(modifier)
    {

    }

    constexpr Dice(StringRef str)
    : m_faces(0)
    , m_count(0)
    , m_modifier(0)
    {
      std::size_t i = 0;
      std::size_t sz = str.getSize();

      while (i < sz && '0' <= str[i] && str[i] <= '9') {
        m_count = m_count * 10 + (str[i] - '0');
        ++i;
      }

      if (i == sz) {
        return;
      }

      if (str[i] != 'd' && str[i] != 'D') {
        return;
      }

      if (m_count == 0) {
        m_count = 1;
      }

      ++i; // eat 'd'

      while (i < sz && '0' <= str[i] && str[i] <= '9') {
        m_faces = m_faces * 10 + (str[i] - '0');
        ++i;
      }

      if (i == sz) {
        return;
      }

      if (str[i] != '+') {
        return;
      }

      ++i; // eat '+'

      while (i < sz && '0' <= str[i] && str[i] <= '9') {
        m_modifier = m_modifier * 10 + (str[i] - '0');
        ++i;
      }
    }

    constexpr int getFaces() const {
      return m_faces;
    }

    constexpr int getCount() const {
      return m_count;
    }

    constexpr int getModifier() const {
      return m_modifier;
    }

    int roll(gf::Random& random) const;

  private:
    int m_faces;
    int m_count;
    int m_modifier;
  };


  namespace literals {

    constexpr gf::Dice operator"" _dice(const char *str, std::size_t sz) {
      return gf::Dice(StringRef(str, sz));
    }

    constexpr gf::Dice operator"" _d4(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(4, static_cast<int>(count));
    }

    constexpr gf::Dice operator"" _d6(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(6, static_cast<int>(count));
    }

    constexpr gf::Dice operator"" _d8(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(8, static_cast<int>(count));
    }

    constexpr gf::Dice operator"" _d10(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(10, static_cast<int>(count));
    }

    constexpr gf::Dice operator"" _d12(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(12, static_cast<int>(count));
    }

    constexpr gf::Dice operator"" _d20(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(20, static_cast<int>(count));
    }

    constexpr gf::Dice operator"" _d100(unsigned long long int count) {
      assert(count <= INT_MAX);
      return gf::Dice(100, static_cast<int>(count));
    }
 }

#ifndef DOXYGEN_SHOULD_SKIP_THIS
}
#endif
}

#endif // GF_DICE_H