vrtreclassifier.h

/******************************************************************************
*
 * Project:  Virtual GDAL Datasets
 * Purpose:  Implementation of Reclassifier
 * Author:   Daniel Baston
 *
 ******************************************************************************
 * Copyright (c) 2025, ISciences LLC
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/
 
#pragma once
 
#include "gdal.h"
#include "cpl_error.h"
 
#include <map>
#include <optional>
#include <utility>
#include <vector>
 
namespace gdal
{

class Reclassifier
{
  public:
    static constexpr char MAPPING_INTERVAL_SEP_CHAR = ';';

    static constexpr char MAPPING_FROMTO_SEP_CHAR = '=';

    struct Interval
    {
        double dfMin;

        double dfMax;

        void SetToConstant(double dfVal);

        CPLErr Parse(const char *pszText, char **end);

        bool IsConstant() const
        {
            return dfMin == dfMax;
        }

        bool Contains(double x) const
        {
            return x >= dfMin && x <= dfMax;
        }

        bool Overlaps(const Interval &other) const;
    };

    CPLErr Init(const char *pszText, std::optional<double> noDataValue,
                GDALDataType eBufType);

    void AddMapping(const Interval &interval, std::optional<double> dfDstVal);

    double Reclassify(double srcVal, bool &bFoundInterval) const;

    void SetDefaultPassThrough(bool value)
    {
        m_defaultPassThrough = value;
    }

    void SetDefaultValue(double value)
    {
        m_defaultValue = value;
    }

    void SetNaNValue(double value)
    {
        m_NaNValue = value;
    }

    CPLErr Finalize();
 
  private:
    std::vector<std::pair<Interval, std::optional<double>>>
        m_aoIntervalMappings{};

    std::optional<double> m_NaNValue{};

    std::optional<double> m_defaultValue{};

    bool m_defaultPassThrough{false};
};
 
}  // namespace gdal