Prepare for public release

.gitattributes

@@ -0,0 +1 @@
+*.pdf filter=lfs diff=lfs merge=lfs -text

README.md

@@ -1,2 +1,32 @@
-# dmr
-Golang Digital Mobile Radio protocols
+# go-dmr
+
+Golang Digital Mobile Radio protocols.
+
+## References
+
+The DMR Air Interface protocol is specified in *Electromagnetic compatibility
+and Radio spectrum Matters (ERM); Digital Mobile Radio (DMR) Systems; Part 1:
+DMR Air Interface (AI) protocol*, [ETSI TS 102 361-1][ETSI TS 102 361-1].
+
+The Brandmeister Homebrew protocol is specified in
+[IPSC Protocol Specs for homebrew DMR repeater][homebrew specs]
+by [Hans DL5DI](mailto:[email protected]),
+[Jonathan Naylor (G4KLXG)](https://twitter.com/g4klx) and Torsten Schultze
+(DG1HT).
+
+[ETSI TS 102 361-1]: docs/ts_10236101v010405p.pdf
+[homebrew specs]: docs/DMRplus%20IPSC%20Protocol%20for%20HB%20repeater%20(20150726).pdf
+
+## Warning
+
+This implementation is not suitable for commercial use and is for educational
+purposes only.
+
+## Acknowledgements
+
+The implementation is possible because of the invaluable help from the
+following persons. Thanks for your patience and providing me with sample data
+and links to test the protocols.
+
+ * Rudy Hardeman (PD0ZRY)
+ * Artem Prilutskiy (R3ABM)

bit/mask.go → bits.go

@@ -1,4 +1,21 @@
-package bit
+package dmr
+
+const (
+	PayloadBits                 = 98 + 10 + 48 + 10 + 98
+	PayloadSize                 = 33
+	InfoHalfBits                = 98
+	InfoBits                    = 2 * InfoHalfBits
+	SlotTypeHalfBits            = 10
+	SlotTypeBits                = 2 * SlotTypeHalfBits
+	SignalBits                  = 48
+	SyncOffsetBits              = InfoHalfBits + SlotTypeHalfBits
+	SyncBits                    = SignalBits
+	VoiceHalfBits               = 108
+	VoiceBits                   = 2 * VoiceHalfBits
+	EMBHalfBits                 = 8
+	EMBBits                     = 2 * EMBHalfBits
+	EMBSignallingLCFragmentBits = 32
+)
 
 // Because Go doesn't have binary literals ("We've found hex and octal to be sufficient")
 const (
@@ -259,3 +276,33 @@ const (
 	B11111110
 	B11111111
 )
+
+// BytesToBits converts a byte slice to a byte slice representing the individual data bits.
+func BytesToBits(data []byte) []byte {
+	var bits = make([]byte, len(data)*8)
+	for i := 0; i < len(data); i++ {
+		copy(bits[i*8:], toBits(data[i]))
+	}
+	return bits
+}
+
+func toBits(b byte) []byte {
+	var o = make([]byte, 8)
+	for bit, mask := 0, byte(128); bit < 8; bit, mask = bit+1, mask>>1 {
+		if b&mask != 0 {
+			o[bit] = 1
+		}
+	}
+	return o
+}
+
+// BitsToBytes converts a byte slice of bits to a byte slice.
+func BitsToBytes(bits []byte) []byte {
+	var data = make([]byte, (len(bits)+7)/8)
+	for i, b := range bits {
+		if b == 0x01 {
+			data[i/8] |= (1 << byte(7-(i%8)))
+		}
+	}
+	return data
+}

bit/bit_test.go → bits_test.go

@@ -1,31 +1,39 @@
-package bit
+package dmr
 
-import "testing"
+import (
+	"bytes"
+	"testing"
+)
 
 func TestBit(t *testing.T) {
 	var tests = []struct {
 		Test []byte
-		Want Bits
+		Want []byte
 	}{
 		{
 			[]byte{0x2a},
-			Bits{0, 0, 1, 0, 1, 0, 1, 0},
+			[]byte{0, 0, 1, 0, 1, 0, 1, 0},
 		},
 		{
 			[]byte{0xbe, 0xef},
-			Bits{1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1},
+			[]byte{1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1},
 		},
 	}
 
 	for _, test := range tests {
-		got := NewBits(test.Test)
+		got := BytesToBits(test.Test)
 		if len(got) != len(test.Want) {
-			t.Fatalf("expected length %d, got %d [%s]", len(test.Want), len(got), got.String())
+			t.Fatalf("expected length %d, got %d [%s]", len(test.Want), len(got), string(got))
 		}
 		for i, b := range got {
 			if b != test.Want[i] {
 				t.Fatalf("bit %d is off: %v != %v", i, got, test.Want)
 			}
 		}
+
+		rev := BitsToBytes(got)
+		if !bytes.Equal(rev, test.Test) {
+			t.Fatalf("reverse bits to bytes failed, %v != %v", rev, test.Test)
+		}
 	}
 }

bptc/bptc.go

@@ -3,11 +3,11 @@ package bptc
 import (
 	"fmt"
 
-	"github.com/tehmaze/go-dmr/bit"
+	"github.com/tehmaze/go-dmr"
 	"github.com/tehmaze/go-dmr/fec"
 )
 
-func Process(info bit.Bits, payload []byte) error {
+func Process(info []byte, payload []byte) error {
 	if len(info) < 196 {
 		return fmt.Errorf("bptc: info size %d too small, need at least 196 bits", len(info))
 	}
@@ -17,8 +17,8 @@ func Process(info bit.Bits, payload []byte) error {
 
 	var (
 		i, j, k   uint32
-		datafr    = make(bit.Bits, 196)
-		extracted = make(bit.Bits, 96)
+		datafr    = make([]byte, 196)
+		extracted = make([]byte, 96)
 	)
 
 	// Deinterleave bits
@@ -41,7 +41,7 @@ func Process(info bit.Bits, payload []byte) error {
 		fec.Hamming15_11_3_Correct(&codeword)
 		codeword &= 0x01ff
 		for j = 0; j < 9; j++ {
-			datafr[j*15+i] = bit.Bit((codeword >> (8 - j)) & 1)
+			datafr[j*15+i] = byte((codeword >> (8 - j)) & 1)
 		}
 	}
 	for j = 0; j < 9; j++ {
@@ -52,7 +52,7 @@ func Process(info bit.Bits, payload []byte) error {
 		}
 		fec.Hamming15_11_3_Correct(&codeword)
 		for i = 0; i < 11; i++ {
-			datafr[j*15+10-i] = bit.Bit((codeword >> i) & 1)
+			datafr[j*15+10-i] = byte((codeword >> i) & 1)
 		}
 	}
 
@@ -66,7 +66,7 @@ func Process(info bit.Bits, payload []byte) error {
 		}
 	}
 
-	copy(payload, extracted.Bytes())
+	copy(payload, dmr.BitsToBytes(extracted))
 
 	return nil
 }