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43 lines
714 B
43 lines
714 B
2 weeks ago
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package utils
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import (
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"encoding/binary"
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)
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const WCPOLY uint16 = 0x8408
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type CRC16CCITT struct {
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wCRCin uint16
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}
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func NewCRC16CCITT() *CRC16CCITT {
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return &CRC16CCITT{}
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}
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func (c *CRC16CCITT) Update(b byte) {
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c.wCRCin ^= uint16(b)
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for j := 0; j < 8; j++ {
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if (c.wCRCin & 0x0001) != 0 {
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c.wCRCin >>= 1
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c.wCRCin ^= WCPOLY
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} else {
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c.wCRCin >>= 1
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}
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}
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}
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func (c *CRC16CCITT) GetWCRCin(rawBytes []byte) []byte {
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for _, b := range rawBytes {
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c.Update(b)
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}
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//log.Printf("CRC16CCITT=0x%x", c.wCRCin)
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return uint16toBytes(c.wCRCin)
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}
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func uint16toBytes(v uint16) []byte {
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littleEndianBytes := make([]byte, 2)
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binary.BigEndian.PutUint16(littleEndianBytes, v)
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return littleEndianBytes
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}
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