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34 lines
1.1 KiB
Go
34 lines
1.1 KiB
Go
package fec
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import "fmt"
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func Golay_20_8_Parity(bits []byte) []byte {
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var p = make([]byte, 12)
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p[0] = bits[1] ^ bits[4] ^ bits[5] ^ bits[6] ^ bits[7]
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p[1] = bits[1] ^ bits[2] ^ bits[4]
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p[2] = bits[0] ^ bits[2] ^ bits[3] ^ bits[5]
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p[3] = bits[0] ^ bits[1] ^ bits[3] ^ bits[4] ^ bits[6]
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p[4] = bits[0] ^ bits[1] ^ bits[2] ^ bits[4] ^ bits[5] ^ bits[7]
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p[5] = bits[0] ^ bits[2] ^ bits[3] ^ bits[4] ^ bits[7]
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p[6] = bits[3] ^ bits[6] ^ bits[7]
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p[7] = bits[0] ^ bits[1] ^ bits[5] ^ bits[6]
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p[8] = bits[0] ^ bits[1] ^ bits[2] ^ bits[6] ^ bits[7]
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p[9] = bits[2] ^ bits[3] ^ bits[4] ^ bits[5] ^ bits[6]
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p[10] = bits[0] ^ bits[3] ^ bits[4] ^ bits[5] ^ bits[6] ^ bits[7]
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p[11] = bits[1] ^ bits[2] ^ bits[3] ^ bits[5] ^ bits[7]
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return p
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}
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func Golay_20_8_Check(bits []byte) error {
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if len(bits) != 20 {
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return fmt.Errorf("fec/golay_20_8: expected 20 bits, got %d", len(bits))
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}
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parity := Golay_20_8_Parity(bits[:8])
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for i := 0; i < 20; i++ {
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if parity[i] != bits[8+i] {
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return fmt.Errorf("fec/golay_20_8: parity error at bit %d: %v != %v", i, parity, bits[8:])
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}
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}
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return nil
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}
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