aria2/src/AlphaNumberDecorator.h

/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#ifndef D_ALPHA_NUMBER_DECORATOR_H
#define D_ALPHA_NUMBER_DECORATOR_H

#include "NumberDecorator.h"
#include "DlAbortEx.h"
#include <algorithm>

namespace aria2 {

class AlphaNumberDecorator : public NumberDecorator
{
private:

  size_t width_;

  char zero_;

  std::string widen(const std::string& s, size_t width)
  {
    std::string t = s;
    std::string zero(1, zero_);
    while(t.size() < width) {
      t.insert(0, zero);
    }
    return t;
  }

public:
  AlphaNumberDecorator(size_t width, bool uppercase = false):
    width_(width), zero_(uppercase?'A':'a') {}

  virtual ~AlphaNumberDecorator() {}

  virtual std::string decorate(unsigned int number)
  {
    if(number == 0) {
      return widen(std::string(1, zero_), width_);
    }

    int base = 26;
    char u[14]; // because if unsigned int is 64bit, which is the biggest integer for the time being and number is UINT64_MAX, you get "HLHXCZMXSYUMQP"
    size_t index = 0;
    do {
      unsigned int quot = number/base;
      unsigned int rem = number%base;
      u[index++] = zero_+rem;
      number = quot;
    } while(number);
    std::reverse(&u[0], &u[index]);

    return widen(std::string(&u[0], &u[index]), width_);
  }
};

} // namespace aria2

#endif // D_ALPHA_NUMBER_DECORATOR_H