VILLASnode/lib/signal.cpp

/* Signal meta data.
 *
 * Author: Steffen Vogel <post@steffenvogel.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#include <villas/exceptions.hpp>
#include <villas/signal.hpp>
#include <villas/utils.hpp>

#include <villas/signal_data.hpp>
#include <villas/signal_type.hpp>

using namespace villas;
using namespace villas::node;
using namespace villas::utils;

Signal::Signal(const std::string &n, const std::string &u, enum SignalType t)
    : name(n), unit(u), init(SignalData::nan()), type(t) {}

int Signal::parse(json_t *json) {
  int ret;
  json_error_t err;
  json_t *json_init = nullptr;
  const char *name_str = nullptr;
  const char *unit_str = nullptr;
  const char *type_str = "float";

  ret = json_unpack_ex(json, &err, 0, "{ s?: s, s?: s, s?: s, s?: o }", "name",
                       &name_str, "unit", &unit_str, "type", &type_str, "init",
                       &json_init);
  if (ret)
    return -1;

  if (name_str)
    name = name_str;

  if (unit_str)
    unit = unit_str;

  if (type_str) {
    type = signalTypeFromString(type_str);
    if (type == SignalType::INVALID)
      return -1;
  }

  if (json_init) {
    ret = init.parseJson(type, json_init);
    if (ret)
      return ret;
  } else
    init.set(type, 0);

  return 0;
}

json_t *Signal::toJson() const {
  json_t *json_sig =
      json_pack("{ s: s }", "type", signalTypeToString(type).c_str());

  auto *json_init = init.toJson(type);
  if (json_init)
    json_object_set_new(json_sig, "init", json_init);

  if (!name.empty())
    json_object_set_new(json_sig, "name", json_string(name.c_str()));

  if (!unit.empty())
    json_object_set_new(json_sig, "unit", json_string(unit.c_str()));

  return json_sig;
}

std::string Signal::toString(const union SignalData *d) const {
  std::stringstream ss;

  if (!name.empty())
    ss << " " << name;

  if (!unit.empty())
    ss << " [" << unit << "]";

  ss << "(" << signalTypeToString(type) << ")";

  if (d)
    ss << " = " << d->toString(type);

  return ss.str();
}

/* Check if two signal names are numbered ascendingly
 *
 * E.g. signal3 -> signal4
 */
static bool isNextName(const std::string &a, const std::string &b) {
  // Find common prefix
  std::string::const_iterator ia, ib;
  for (ia = a.cbegin(), ib = b.cbegin();
       ia != b.cend() && ib != b.cend() && *ia == *ib; ++ia, ++ib)
    ;

  // Suffixes
  auto sa = std::string(ia, a.cend());
  auto sb = std::string(ib, b.cend());

  try {
    size_t ea, eb;
    auto na = std::stoul(sa, &ea, 10);
    auto nb = std::stoul(sb, &eb, 10);

    return na + 1 == nb;
  } catch (std::exception &) {
    return false;
  }
}

bool Signal::isNext(const Signal &sig) {
  if (type != sig.type)
    return false;

  if (!unit.empty() && !sig.unit.empty() && unit != sig.unit)
    return false;

  return isNextName(name, sig.name);
}