Zabbix

/*

** Zabbix

** Copyright (C) 2001-2022 Zabbix SIA

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU General Public License as published by

** the Free Software Foundation; either version 2 of the License, or

** (at your option) any later version.

**

** This program is distributed in the hope that it will be useful,

** but WITHOUT ANY WARRANTY; without even the implied warranty of

** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

** GNU General Public License for more details.

**

** You should have received a copy of the GNU General Public License

** along with this program; if not, write to the Free Software

** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

**/

​

package modbus

​

import (

    "bytes"

    "encoding/binary"

    "encoding/json"

    "fmt"

)

​

// main data transformation

func pack2Json(val []byte, p *mbParams) (jdata interface{}, err error) {

​

    if p.RetType == Bit {

        ar := getArr16(p.RetType, uint(p.Count), val)

        if p.RetCount == 1 {

            return getFirst(ar), nil

        }

​

        if len(ar) < int(p.Offset) {

            return nil, fmt.Errorf("Wrong length of received data: %d", len(ar))

        }

​

        if p.Offset > 0 {

            ar = ar[p.Offset:]

        }

​

        jd, jerr := json.Marshal(ar)

        if jerr != nil {

            return nil, fmt.Errorf("Unable to create json: %s", jerr)

        }

        return string(jd), nil

    }

​

    if len(val) < int(p.Offset*2) {

        return nil, fmt.Errorf("Wrong length of received data: %d", len(val))

    }

​

    if p.Offset > 0 {

        val = val[p.Offset*2:]

    }

​

    var typeSize int

    switch p.RetType {

    case Uint64, Double:

        typeSize = 8

    case Int32, Uint32, Float:

        typeSize = 4

    case Int16, Uint16:

        typeSize = 2

    default:

        typeSize = 1

    }

​

    var arr interface{}

    if typeSize == 1 && p.Endianness.order == binary.LittleEndian {

        arr = swapPairByte(val, p.RetType, p.RetCount)

    } else {

        arr = makeRetArray(p.RetType, p.RetCount)

        r := bytes.NewReader(val)

        if err = binary.Read(r, p.Endianness.order, arr); err != nil {

            return nil, fmt.Errorf("Unable to convert returned data: %w", err)

        }

    }

​

    if typeSize > 2 && 0 != p.Endianness.middle {

        arr = middlePack(arr, p.RetType)

    }

​

    if p.RetCount == 1 {

        return getFirst(arr), nil

    }

​