39 lines
1.5 KiB
Go
39 lines
1.5 KiB
Go
package gateway
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import (
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"encoding/binary"
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"errors"
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)
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var ErrInputMalformed = errors.New("input event malformed")
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func EncodeInputEvent(event InputEvent) ([]byte, error) {
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if len(event.Device) == 0 || len(event.Device) > 64 || len(event.Payload) > 1024 {
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return nil, ErrInputMalformed
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}
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encoded := make([]byte, 16+len(event.Device)+len(event.Payload))
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copy(encoded[:4], "INP1")
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binary.BigEndian.PutUint32(encoded[4:8], event.Sequence)
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binary.BigEndian.PutUint32(encoded[8:12], uint32(event.Code))
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if event.Pressed {
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encoded[12] = 1
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}
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encoded[13] = byte(len(event.Device))
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binary.BigEndian.PutUint16(encoded[14:16], uint16(len(event.Payload)))
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copy(encoded[16:16+len(event.Device)], event.Device)
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copy(encoded[16+len(event.Device):], event.Payload)
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return encoded, nil
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}
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func DecodeInputEvent(data []byte) (InputEvent, error) {
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if len(data) < 16 || len(data) > 1179 || string(data[:4]) != "INP1" || (data[12] != 0 && data[12] != 1) {
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return InputEvent{}, ErrInputMalformed
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}
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deviceLength := int(data[13])
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payloadLength := int(binary.BigEndian.Uint16(data[14:16]))
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if deviceLength == 0 || deviceLength > 64 || payloadLength > 1024 || len(data) != 16+deviceLength+payloadLength {
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return InputEvent{}, ErrInputMalformed
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}
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return InputEvent{Sequence: binary.BigEndian.Uint32(data[4:8]), Code: int32(binary.BigEndian.Uint32(data[8:12])), Pressed: data[12] == 1, Device: string(data[16 : 16+deviceLength]), Payload: append([]byte(nil), data[16+deviceLength:]...)}, nil
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}
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