git.giacomolli.uk - onehouse/blob - driver/m31/output_request.go

   1 package m31
   2
   3 import (
   4         "bytes"
   5         "encoding/json"
   6         "math"
   7         "math/big"
   8         "time"
   9
  10         "onehouse/driver"
  11 )
  12
  13 type outputRequest struct {
  14         command driver.Command
  15         point   point
  16         analog  bool
  17         value   uint16
  18 }
  19
  20 func newOutputRequest(command driver.Command, topology topology, deviceID string, batch bool) (outputRequest, string) {
  21         request := outputRequest{command: command}
  22
  23         if command.DeviceID != deviceID {
  24                 return request, "Command belongs to another device"
  25         }
  26
  27         if command.Expired(time.Now()) {
  28                 return request, "Command expired"
  29         }
  30
  31         value := bytes.TrimSpace(command.Payload.Value)
  32
  33         for _, output := range topology.outputs {
  34                 if output.id != command.Capability {
  35                         continue
  36                 }
  37
  38                 request.point = output
  39                 if !bytes.Equal(value, []byte("true")) && !bytes.Equal(value, []byte("false")) {
  40                         return request, "Digital output requires a Boolean value"
  41                 }
  42
  43                 if bytes.Equal(value, []byte("true")) {
  44                         request.value = 1
  45                 }
  46
  47                 if output.pulse != 0 && request.value != 1 {
  48                         return request, "Pulse output requires true"
  49                 }
  50
  51                 if batch && output.pulse != 0 {
  52                         return request, "Batches require steady digital outputs"
  53                 }
  54
  55                 return request, ""
  56         }
  57
  58         for _, output := range topology.analog {
  59                 if output.id != command.Capability {
  60                         continue
  61                 }
  62
  63                 request.point, request.analog = output, true
  64                 if batch {
  65                         return request, "Batches require steady digital outputs"
  66                 }
  67
  68                 if len(value) == 0 || !json.Valid(value) || value[0] != '-' && (value[0] < '0' || value[0] > '9') {
  69                         return request, "Analog output requires zero through ten volts"
  70                 }
  71
  72                 number, valid := new(big.Rat).SetString(string(value))
  73                 if !valid || number.Sign() < 0 || number.Cmp(big.NewRat(10, 1)) > 0 {
  74                         return request, "Analog output requires zero through ten volts"
  75                 }
  76
  77                 voltage, _ := number.Float64()
  78                 request.value = uint16(math.Round(voltage * 1000))
  79
  80                 return request, ""
  81         }
  82
  83         return request, "Capability is not a configured output"
  84 }