O_C

// Copyright 2015 Olivier Gillet, 2016 mxmxmx
//
// Author: Olivier Gillet (ol.gillet@gmail.com)
// adapted for OC, mxmxmx
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
// 
// See http://creativecommons.org/licenses/MIT/ for more information.
//
// -----------------------------------------------------------------------------
//
// input mapping, based on braids quantizer

#include "OC_input_map.h"
#include "Arduino.h"
#include <algorithm>
#include <cstdlib>

namespace OC {


void Input_Map::Init() {
  enabled_ = true;
  update_ = false;
  code_index_ = 0;
  previous_boundary_ = 0;
  next_boundary_ = 0;
  num_slots_ = 15;
  for (int16_t i = 0; i < 16; ++i) {
    codebook_[i] = i << 7;
  }
}

void Input_Map::Configure(const int8_t num_slots, const int16_t* ranges, uint8_t range) {

  enabled_ = ranges != NULL;

  if (enabled_) {
  
    int16_t delta = ranges[range];

    for (int32_t i = 0; i < 16; ++i) {
      codebook_[i] = delta*i;
    }
    update_ = true;
    num_slots_ = num_slots;
  }
}

int8_t Input_Map::Process(int32_t input) {

  int8_t _slot = 0;

  if (!enabled_) {
    return _slot;
  }

  if (!update_ && input >= previous_boundary_ && input <= next_boundary_) {
    // We're still in the voronoi cell for the active codeword.
    _slot = code_index_;
  } else {
    // Search for the nearest neighbour in the codebook.
    int16_t upper_bound_index = std::upper_bound(
        &codebook_[2],
        &codebook_[15],
        static_cast<int16_t>(input)) - &codebook_[0];
    int16_t lower_bound_index = upper_bound_index - 2;

    int16_t best_distance = 512;
    int16_t q = -1;
    for (int16_t i = lower_bound_index; i <= upper_bound_index; ++i) {
      int16_t distance = abs(input - codebook_[i]);
      if (distance < best_distance) {
        best_distance = distance;
        q = i;
      }
    }

    // Enlarge the current voronoi cell a bit for hysteresis.
    previous_boundary_ = (9 * codebook_[q - 1] + 7 * codebook_[q]) >> 4;
    next_boundary_ = (9 * codebook_[q + 1] + 7 * codebook_[q]) >> 4;

    if (q < 0) q = 0;
    else if (q > num_slots_) q = num_slots_;
    code_index_ = _slot = q;
    update_ = false;
  }
  return _slot;
}


}  // namespace OC