/**********************************************************************

 * File:        mod128.h  (Formerly dir128.h)

 * Description: Header for class which implements modulo arithmetic.

 * Author:      Ray Smith

 *

 * (C) Copyright 1991, Hewlett-Packard Ltd.

 ** Licensed under the Apache License, Version 2.0 (the "License");

 ** you may not use this file except in compliance with the License.

 ** You may obtain a copy of the License at

 ** http://www.apache.org/licenses/LICENSE-2.0

 ** Unless required by applicable law or agreed to in writing, software

 ** distributed under the License is distributed on an "AS IS" BASIS,

 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 ** See the License for the specific language governing permissions and

 ** limitations under the License.

 *

 **********************************************************************/

#ifndef MOD128_H

#define MOD128_H

#include "points.h"

namespace tesseract {

#define MODULUS 128   /*range of directions */

#define DIRBITS 7     // no of bits used

#define DIRSCALE 1000 // length of vector

class DIR128 {

public:

  DIR128() = default;

  DIR128(              // constructor

      int16_t value) { // value to assign

    value %= MODULUS;  // modulo arithmetic

    if (value < 0) {

      value += MODULUS; // done properly

    }

    dir = static_cast<int8_t>(value);

  }

  DIR128(const FCOORD fc); // quantize vector

  DIR128 &operator=(   // assign of int16_t

      int16_t value) { // value to assign

    value %= MODULUS;  // modulo arithmetic

    if (value < 0) {

      value += MODULUS; // done properly

    }

    dir = static_cast<int8_t>(value);

    return *this;

  }

  int8_t operator-(              // subtraction

      const DIR128 &minus) const // for signed result

  {

    // result

    int16_t result = dir - minus.dir;

    if (result > MODULUS / 2) {

      result -= MODULUS; // get in range

    } else if (result < -MODULUS / 2) {

      result += MODULUS;

    }

    return static_cast<int8_t>(result);

  }

  DIR128 operator+(            // addition

      const DIR128 &add) const // of itself

  {

    DIR128 result; // sum

    result = dir + add.dir; // let = do the work

    return result;

  }

  DIR128 &operator+=( // same as +

      const DIR128 &add) {

    *this = dir + add.dir; // let = do the work

    return *this;

  }

  int8_t get_dir() const { // access function

    return dir;

  }

  int8_t dir; // a direction

};

} // namespace tesseract

#endif