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50 lines
1002 B
Go
50 lines
1002 B
Go
9 years ago
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package dmr
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import (
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"errors"
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"fmt"
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"github.com/pd0mz/go-dmr/bit"
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"github.com/pd0mz/go-dmr/crc/quadres_16_7"
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)
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// EMB LCSS fragments
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const (
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SingleFragment uint8 = iota
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FirstFragment
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LastFragment
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Continuation
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)
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func ExtractEMBBitsFromSyncBits(sync bit.Bits) bit.Bits {
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var b = make(bit.Bits, EMBBits)
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var o = EMBHalfBits + EMBSignallingLCFragmentBits
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copy(b[:EMBHalfBits], sync[:EMBHalfBits])
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copy(b[EMBHalfBits:], sync[o:o+EMBHalfBits])
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return b
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}
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type EMB struct {
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ColorCode uint8
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LCSS uint8
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}
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func ParseEMB(bits bit.Bits) (*EMB, error) {
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if len(bits) != EMBBits {
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return nil, fmt.Errorf("dmr/emb: expected %d bits, got %d", EMBBits, len(bits))
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}
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if !quadres_16_7.Check(bits) {
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return nil, errors.New("dmr/emb: checksum error")
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}
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if bits[4] != 0 {
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return nil, errors.New("dmr/emb: pi is not 0")
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}
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return &EMB{
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ColorCode: uint8(bits[0])<<3 | uint8(bits[1])<<2 | uint8(bits[2])<<1 | uint8(bits[3]),
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LCSS: uint8(bits[5])<<1 | uint8(bits[6]),
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}, nil
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}
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