fix

zhangqian

2023-09-25 cf96f6bc1fb484fde16bd5ed6d49534c96958022

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package modbusx
 
import (
    "encoding/binary"
    "sync/atomic"
)
 
func Read(ipAddr string, address uint16, quantity uint16) (data []byte, err error) {
    address--
    cli := getModbusConnection(ipAddr)
    data, err = cli.ReadHoldingRegisters(address, quantity)
    dealErr(err, ipAddr)
    if err != nil {
        cli = getModbusConnection(ipAddr)
        data, err = cli.ReadHoldingRegisters(address, quantity)
        dealErr(err, ipAddr)
    }
    return
}
 
func Write(ipAddr string, address uint16, value int) (err error) {
    address--
    var bytesVal []byte
    bytesVal = intToBytes(value)
    cli := getModbusConnection(ipAddr)
    _, err = cli.WriteMultipleRegisters(address, uint16(len(bytesVal)), bytesVal)
    dealErr(err, ipAddr)
    return err
}
 
func intToBytes(value int) (data []byte) {
    if value <= 1<<16 {
        data = make([]byte, 2)
        binary.BigEndian.PutUint16(data, uint16(value))
    } else {
        data = make([]byte, 4)
        binary.BigEndian.PutUint32(data, uint32(value))
    }
    return
}
 
func dealErr(err error, ipAddr string) {
    if err != nil {
        unsetModbusConnection(ipAddr)       //失败则删除缓存的连接
        FailureRemainingOpportunitiesDecr() //减少失败剩余机会
    } else {
        FailureRemainingOpportunitiesReset() //重置失败剩余机会
    }
}
 
var connectionStatus atomic.Bool
 
var failureRemainingOpportunities atomic.Int64
 
const (
    defaultFailureRemainingOpportunities = 20
)
 
func IsConnect() bool {
    return connectionStatus.Load()
}
 
func FailureRemainingOpportunitiesDecr() {
    newValue := failureRemainingOpportunities.Add(-1)
    if newValue <= 0 {
        connectionStatus.Store(false)
    }
    return
}
 
func FailureRemainingOpportunitiesReset() {
    if failureRemainingOpportunities.Load() < defaultFailureRemainingOpportunities {
        failureRemainingOpportunities.Store(defaultFailureRemainingOpportunities)
    }
    if connectionStatus.Load() == false {
        connectionStatus.Store(true)
    }
    return
}