json-validator/include/jvalidate/constraint/number_constraint.h

#pragma once

#include <cmath>
#include <limits>

#include <jvalidate/detail/number.h>
#include <jvalidate/forward.h>

namespace jvalidate::constraint {
/**
 * @brief A constraint on the Int and Double types, asserting that the given
 * arg is less than the stored value. Equality is accepted or rejected based
 * on exclusive being true or not.
 * Unlike other constraint types, numeric constraints are trivial and thus
 * are implemented directly in the constraint object.
 *
 * https://json-schema.org/draft/2020-12/json-schema-validation#section-6.2.2
 * https://json-schema.org/draft/2020-12/json-schema-validation#section-6.2.3
 */
struct MaximumConstraint {
  double value;
  bool exclusive;

  bool operator()(double arg) const { return exclusive ? arg < value : arg <= value; }
};

/**
 * @brief A constraint on the Int and Double types, asserting that the given
 * arg is greater than the stored value. Equality is accepted or rejected based
 * on exclusive being true or not.
 * Unlike other constraint types, numeric constraints are trivial and thus
 * are implemented directly in the constraint object.
 *
 * https://json-schema.org/draft/2020-12/json-schema-validation#section-6.2.4
 * https://json-schema.org/draft/2020-12/json-schema-validation#section-6.2.5
 */
struct MinimumConstraint {
  double value;
  bool exclusive;

  bool operator()(double arg) const { return exclusive ? arg > value : arg >= value; }
};

/**
 * @brief A constraint on the Int and Double types, asserting that the given
 * arg is a multiple of the stored value.
 * Unlike other constraint types, numeric constraints are trivial and thus
 * are implemented directly in the constraint object.
 *
 * https://json-schema.org/draft/2020-12/json-schema-validation#section-6.2.1
 */
struct MultipleOfConstraint {
  double value;

  bool operator()(double arg) const {
    if (std::fabs(std::remainder(arg, value)) <= std::numeric_limits<double>::epsilon()) {
      return true;
    }

    double const div = arg / value;
    return std::isfinite(div) && detail::is_json_integer(div);
  }
};
}