modbus_helpers.h

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#pragma once
 
#include <string>
#include <vector>
#include <cmath>
 
#include "esphome/core/helpers.h"
#include "esphome/components/modbus/modbus_definitions.h"
 
namespace esphome::modbus::helpers {
 
enum class SensorValueType : uint8_t {
  RAW = 0x00,     // variable length
  U_WORD = 0x1,   // 1 Register unsigned
  U_DWORD = 0x2,  // 2 Registers unsigned
  S_WORD = 0x3,   // 1 Register signed
  S_DWORD = 0x4,  // 2 Registers signed
  BIT = 0x5,
  U_DWORD_R = 0x6,  // 2 Registers unsigned
  S_DWORD_R = 0x7,  // 2 Registers unsigned
  U_QWORD = 0x8,
  S_QWORD = 0x9,
  U_QWORD_R = 0xA,
  S_QWORD_R = 0xB,
  FP32 = 0xC,
  FP32_R = 0xD
};
 
inline bool value_type_is_float(SensorValueType v) {
  return v == SensorValueType::FP32 || v == SensorValueType::FP32_R;
}
 
inline ModbusFunctionCode modbus_register_read_function(ModbusRegisterType reg_type) {
  switch (reg_type) {
    case ModbusRegisterType::COIL:
      return ModbusFunctionCode::READ_COILS;
    case ModbusRegisterType::DISCRETE_INPUT:
      return ModbusFunctionCode::READ_DISCRETE_INPUTS;
    case ModbusRegisterType::HOLDING:
      return ModbusFunctionCode::READ_HOLDING_REGISTERS;
    case ModbusRegisterType::READ:
      return ModbusFunctionCode::READ_INPUT_REGISTERS;
    default:
      return ModbusFunctionCode::CUSTOM;
  }
}
 
inline ModbusFunctionCode modbus_register_write_function(ModbusRegisterType reg_type) {
  switch (reg_type) {
    case ModbusRegisterType::COIL:
      return ModbusFunctionCode::WRITE_SINGLE_COIL;
    case ModbusRegisterType::DISCRETE_INPUT:
      return ModbusFunctionCode::CUSTOM;
    case ModbusRegisterType::HOLDING:
      return ModbusFunctionCode::READ_WRITE_MULTIPLE_REGISTERS;
    case ModbusRegisterType::READ:
    default:
      return ModbusFunctionCode::CUSTOM;
  }
}
 
inline uint8_t c_to_hex(char c) { return (c >= 'A') ? (c >= 'a') ? (c - 'a' + 10) : (c - 'A' + 10) : (c - '0'); }
 
inline uint8_t byte_from_hex_str(const std::string &value, uint8_t pos) {
  if (value.length() < pos * 2 + 2)
    return 0;
  return (c_to_hex(value[pos * 2]) << 4) | c_to_hex(value[pos * 2 + 1]);
}
 
inline uint16_t word_from_hex_str(const std::string &value, uint8_t pos) {
  return byte_from_hex_str(value, pos) << 8 | byte_from_hex_str(value, pos + 1);
}
 
inline uint32_t dword_from_hex_str(const std::string &value, uint8_t pos) {
  return word_from_hex_str(value, pos) << 16 | word_from_hex_str(value, pos + 2);
}
 
inline uint64_t qword_from_hex_str(const std::string &value, uint8_t pos) {
  return static_cast<uint64_t>(dword_from_hex_str(value, pos)) << 32 | dword_from_hex_str(value, pos + 4);
}
 
// Extract data from modbus response buffer
template<typename T> T get_data(const std::vector<uint8_t> &data, size_t buffer_offset) {
  if (sizeof(T) == sizeof(uint8_t)) {
    return T(data[buffer_offset]);
  }
  if (sizeof(T) == sizeof(uint16_t)) {
    return T((uint16_t(data[buffer_offset + 0]) << 8) | (uint16_t(data[buffer_offset + 1]) << 0));
  }
 
  if (sizeof(T) == sizeof(uint32_t)) {
    return static_cast<uint32_t>(get_data<uint16_t>(data, buffer_offset)) << 16 |
           static_cast<uint32_t>(get_data<uint16_t>(data, buffer_offset + 2));
  }
 
  if (sizeof(T) == sizeof(uint64_t)) {
    return static_cast<uint64_t>(get_data<uint32_t>(data, buffer_offset)) << 32 |
           (static_cast<uint64_t>(get_data<uint32_t>(data, buffer_offset + 4)));
  }
 
  static_assert(sizeof(T) == sizeof(uint8_t) || sizeof(T) == sizeof(uint16_t) || sizeof(T) == sizeof(uint32_t) ||
                    sizeof(T) == sizeof(uint64_t),
                "Unsupported type size in get_data; only 1, 2, 4, or 8-byte integer types are supported.");
 
  return T{};
}
 
inline bool coil_from_vector(int coil, const std::vector<uint8_t> &data) {
  auto data_byte = coil / 8;
  return (data[data_byte] & (1 << (coil % 8))) > 0;
}
 
template<typename N> N mask_and_shift_by_rightbit(N data, uint32_t mask) {
  auto result = (mask & data);
  if (result == 0 || mask == 0xFFFFFFFF) {
    return result;
  }
  for (size_t pos = 0; pos < sizeof(N) << 3; pos++) {
    if (pos < 32 && (mask & (1UL << pos)) != 0)
      return result >> pos;
  }
  return 0;
}
 
void number_to_payload(std::vector<uint16_t> &data, int64_t value, SensorValueType value_type);
 
int64_t payload_to_number(const std::vector<uint8_t> &data, SensorValueType sensor_value_type, uint8_t offset,
                          uint32_t bitmask);
 
inline std::vector<uint16_t> float_to_payload(float value, SensorValueType value_type) {
  int64_t val;
 
  if (value_type_is_float(value_type)) {
    val = bit_cast<uint32_t>(value);
  } else {
    val = llroundf(value);
  }
 
  std::vector<uint16_t> data;
  number_to_payload(data, val, value_type);
  return data;
}
 
}  // namespace esphome::modbus::helpers