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37 lines
549 B
37 lines
549 B
package misc
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const (
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iBm = 0xA001
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)
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type tABLe [256]uint16
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var ibmTable = makeTable(iBm)
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func makeTable(poly uint16) *tABLe {
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t := new(tABLe)
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for i := 0; i < 256; i++ {
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crc := uint16(i)
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for j := 0; j < 8; j++ {
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if crc&1 == 1 {
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crc = (crc >> 1) ^ poly
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} else {
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crc >>= 1
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}
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}
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t[i] = crc
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}
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return t
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}
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func update(crc uint16, tab *tABLe, p []byte) uint16 {
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crc = ^crc
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for _, v := range p {
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crc = tab[byte(crc)^v] ^ (crc >> 8)
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}
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return ^crc
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}
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func CRC16(data []byte) uint16 {
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return update(0, ibmTable, data)
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}
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