fixes issue #12

due to a race condition some DM codes were created incorrectly

datamatrix/codelayout.go

@@ -2,6 +2,7 @@ package datamatrix
 
 import (
 	"github.com/boombuler/barcode/utils"
+	"strconv"
 )
 
 type setValFunc func(byte)
@@ -24,7 +25,7 @@ func (l *codeLayout) Occupied(row, col int) bool {
 	return l.occupy.GetBit(col + row*l.size.MatrixColumns())
 }
 
-func (l *codeLayout) Set(row, col int, value, bitNum byte, occupy bool) {
+func (l *codeLayout) Set(row, col int, value, bitNum byte) {
 	val := ((value >> (7 - bitNum)) & 1) == 1
 	if row < 0 {
 		row += l.size.MatrixRows()
@@ -34,128 +35,127 @@ func (l *codeLayout) Set(row, col int, value, bitNum byte, occupy bool) {
 		col += l.size.MatrixColumns()
 		row += 4 - ((l.size.MatrixColumns() + 4) % 8)
 	}
-	l.matrix.SetBit(col+row*l.size.MatrixColumns(), val)
-	if occupy {
-		l.occupy.SetBit(col+row*l.size.MatrixColumns(), true)
+	if l.Occupied(row, col) {
+		panic("Field already occupied row: " + strconv.Itoa(row) + " col: " + strconv.Itoa(col))
 	}
+
+	l.occupy.SetBit(col+row*l.size.MatrixColumns(), true)
+
+	l.matrix.SetBit(col+row*l.size.MatrixColumns(), val)
 }
 
 func (l *codeLayout) SetSimple(row, col int, value byte) {
-	l.Set(row-2, col-2, value, 0, true)
-	l.Set(row-2, col-1, value, 1, true)
-	l.Set(row-1, col-2, value, 2, true)
-	l.Set(row-1, col-1, value, 3, true)
-	l.Set(row-1, col-0, value, 4, true)
-	l.Set(row-0, col-2, value, 5, true)
-	l.Set(row-0, col-1, value, 6, true)
-	l.Set(row-0, col-0, value, 7, true)
+	l.Set(row-2, col-2, value, 0)
+	l.Set(row-2, col-1, value, 1)
+	l.Set(row-1, col-2, value, 2)
+	l.Set(row-1, col-1, value, 3)
+	l.Set(row-1, col-0, value, 4)
+	l.Set(row-0, col-2, value, 5)
+	l.Set(row-0, col-1, value, 6)
+	l.Set(row-0, col-0, value, 7)
 }
 
 func (l *codeLayout) Corner1(value byte) {
-	l.Set(l.size.MatrixRows()-1, 0, value, 0, true)
-	l.Set(l.size.MatrixRows()-1, 1, value, 1, true)
-	l.Set(l.size.MatrixRows()-1, 2, value, 2, true)
-	l.Set(0, l.size.MatrixColumns()-2, value, 3, true)
-	l.Set(0, l.size.MatrixColumns()-1, value, 4, true)
-	l.Set(1, l.size.MatrixColumns()-1, value, 5, true)
-	l.Set(2, l.size.MatrixColumns()-1, value, 6, true)
-	l.Set(3, l.size.MatrixColumns()-1, value, 7, true)
+	l.Set(l.size.MatrixRows()-1, 0, value, 0)
+	l.Set(l.size.MatrixRows()-1, 1, value, 1)
+	l.Set(l.size.MatrixRows()-1, 2, value, 2)
+	l.Set(0, l.size.MatrixColumns()-2, value, 3)
+	l.Set(0, l.size.MatrixColumns()-1, value, 4)
+	l.Set(1, l.size.MatrixColumns()-1, value, 5)
+	l.Set(2, l.size.MatrixColumns()-1, value, 6)
+	l.Set(3, l.size.MatrixColumns()-1, value, 7)
 }
 
 func (l *codeLayout) Corner2(value byte) {
-	l.Set(l.size.MatrixRows()-3, 0, value, 0, true)
-	l.Set(l.size.MatrixRows()-2, 0, value, 1, true)
-	l.Set(l.size.MatrixRows()-1, 0, value, 2, true)
-	l.Set(0, l.size.MatrixColumns()-4, value, 3, true)
-	l.Set(0, l.size.MatrixColumns()-3, value, 4, true)
-	l.Set(0, l.size.MatrixColumns()-2, value, 5, true)
-	l.Set(0, l.size.MatrixColumns()-1, value, 6, true)
-	l.Set(1, l.size.MatrixColumns()-1, value, 7, true)
+	l.Set(l.size.MatrixRows()-3, 0, value, 0)
+	l.Set(l.size.MatrixRows()-2, 0, value, 1)
+	l.Set(l.size.MatrixRows()-1, 0, value, 2)
+	l.Set(0, l.size.MatrixColumns()-4, value, 3)
+	l.Set(0, l.size.MatrixColumns()-3, value, 4)
+	l.Set(0, l.size.MatrixColumns()-2, value, 5)
+	l.Set(0, l.size.MatrixColumns()-1, value, 6)
+	l.Set(1, l.size.MatrixColumns()-1, value, 7)
 }
 
 func (l *codeLayout) Corner3(value byte) {
-	l.Set(l.size.MatrixRows()-3, 0, value, 0, true)
-	l.Set(l.size.MatrixRows()-2, 0, value, 1, true)
-	l.Set(l.size.MatrixRows()-1, 0, value, 2, true)
-	l.Set(0, l.size.MatrixColumns()-2, value, 3, true)
-	l.Set(0, l.size.MatrixColumns()-1, value, 4, true)
-	l.Set(1, l.size.MatrixColumns()-1, value, 5, true)
-	l.Set(2, l.size.MatrixColumns()-1, value, 6, true)
-	l.Set(3, l.size.MatrixColumns()-1, value, 7, true)
+	l.Set(l.size.MatrixRows()-3, 0, value, 0)
+	l.Set(l.size.MatrixRows()-2, 0, value, 1)
+	l.Set(l.size.MatrixRows()-1, 0, value, 2)
+	l.Set(0, l.size.MatrixColumns()-2, value, 3)
+	l.Set(0, l.size.MatrixColumns()-1, value, 4)
+	l.Set(1, l.size.MatrixColumns()-1, value, 5)
+	l.Set(2, l.size.MatrixColumns()-1, value, 6)
+	l.Set(3, l.size.MatrixColumns()-1, value, 7)
 }
 
 func (l *codeLayout) Corner4(value byte) {
-	l.Set(l.size.MatrixRows()-1, 0, value, 0, true)
-	l.Set(l.size.MatrixRows()-1, l.size.MatrixColumns()-1, value, 1, true)
-	l.Set(0, l.size.MatrixColumns()-3, value, 2, true)
-	l.Set(0, l.size.MatrixColumns()-2, value, 3, true)
-	l.Set(0, l.size.MatrixColumns()-1, value, 4, true)
-	l.Set(1, l.size.MatrixColumns()-3, value, 5, true)
-	l.Set(1, l.size.MatrixColumns()-2, value, 6, true)
-	l.Set(1, l.size.MatrixColumns()-1, value, 7, true)
+	l.Set(l.size.MatrixRows()-1, 0, value, 0)
+	l.Set(l.size.MatrixRows()-1, l.size.MatrixColumns()-1, value, 1)
+	l.Set(0, l.size.MatrixColumns()-3, value, 2)
+	l.Set(0, l.size.MatrixColumns()-2, value, 3)
+	l.Set(0, l.size.MatrixColumns()-1, value, 4)
+	l.Set(1, l.size.MatrixColumns()-3, value, 5)
+	l.Set(1, l.size.MatrixColumns()-2, value, 6)
+	l.Set(1, l.size.MatrixColumns()-1, value, 7)
 }
 
-func (l *codeLayout) IterateSetter() <-chan setValFunc {
-	result := make(chan setValFunc)
-	go func() {
-		row := 4
-		col := 0
+func (l *codeLayout) SetValues(data []byte) {
+	idx := 0
+	row := 4
+	col := 0
 
-		for (row < l.size.MatrixRows()) || (col < l.size.MatrixColumns()) {
-			if (row == l.size.MatrixRows()) && (col == 0) {
-				result <- l.Corner1
-			}
-			if (row == l.size.MatrixRows()-2) && (col == 0) && (l.size.MatrixColumns()%4 != 0) {
-				result <- l.Corner2
-			}
-			if (row == l.size.MatrixRows()-2) && (col == 0) && (l.size.MatrixColumns()%8 == 4) {
-				result <- l.Corner3
-			}
+	for (row < l.size.MatrixRows()) || (col < l.size.MatrixColumns()) {
+		if (row == l.size.MatrixRows()) && (col == 0) {
+			l.Corner1(data[idx])
+			idx++
+		}
+		if (row == l.size.MatrixRows()-2) && (col == 0) && (l.size.MatrixColumns()%4 != 0) {
+			l.Corner2(data[idx])
+			idx++
+		}
+		if (row == l.size.MatrixRows()-2) && (col == 0) && (l.size.MatrixColumns()%8 == 4) {
+			l.Corner3(data[idx])
+			idx++
+		}
 
-			if (row == l.size.MatrixRows()+4) && (col == 2) && (l.size.MatrixColumns()%8 == 0) {
-				result <- l.Corner4
-			}
+		if (row == l.size.MatrixRows()+4) && (col == 2) && (l.size.MatrixColumns()%8 == 0) {
+			l.Corner4(data[idx])
+			idx++
+		}
 
-			for true {
-				if (row < l.size.MatrixRows()) && (col >= 0) && !l.Occupied(row, col) {
-					r := row
-					c := col
-					result <- func(b byte) {
-						l.SetSimple(r, c, b)
-					}
-				}
-				row -= 2
-				col += 2
-				if (row < 0) || (col >= l.size.MatrixColumns()) {
-					break
-				}
+		for true {
+			if (row < l.size.MatrixRows()) && (col >= 0) && !l.Occupied(row, col) {
+				l.SetSimple(row, col, data[idx])
+				idx++
 			}
-
-			row += 1
-			col += 3
-
-			for true {
-				if (row >= 0) && (col < l.size.MatrixColumns()) && !l.Occupied(row, col) {
-					r := row
-					c := col
-					result <- func(b byte) {
-						l.SetSimple(r, c, b)
-					}
-				}
-				row += 2
-				col -= 2
-				if (row >= l.size.MatrixRows()) || (col < 0) {
-					break
-				}
+			row -= 2
+			col += 2
+			if (row < 0) || (col >= l.size.MatrixColumns()) {
+				break
 			}
-			row += 3
-			col += 1
+		}
+		row += 1
+		col += 3
 
+		for true {
+			if (row >= 0) && (col < l.size.MatrixColumns()) && !l.Occupied(row, col) {
+				l.SetSimple(row, col, data[idx])
+				idx++
+			}
+			row += 2
+			col -= 2
+			if (row >= l.size.MatrixRows()) || (col < 0) {
+				break
+			}
 		}
-		close(result)
-	}()
+		row += 3
+		col += 1
+	}
 
-	return result
+	if !l.Occupied(l.size.MatrixRows()-1, l.size.MatrixColumns()-1) {
+		l.Set(l.size.MatrixRows()-1, l.size.MatrixColumns()-1, 255, 0)
+		l.Set(l.size.MatrixRows()-2, l.size.MatrixColumns()-2, 255, 0)
+	}
 }
 
 func (l *codeLayout) Merge() *datamatrixCode {

datamatrix/datamatrix_test.go

@@ -0,0 +1,102 @@
+package datamatrix
+
+import (
+	"bytes"
+	"testing"
+)
+
+func codeFromStr(str string, size *dmCodeSize) *datamatrixCode {
+	code := newDataMatrixCode(size)
+	idx := 0
+	for _, r := range str {
+		x := idx % size.Columns
+		y := idx / size.Columns
+
+		switch r {
+		case '#':
+			code.set(x, y, true)
+		case '.':
+			code.set(x, y, false)
+		default:
+			continue
+		}
+
+		idx++
+	}
+	return code
+}
+
+func Test_Issue12(t *testing.T) {
+	data := `{"po":12,"batchAction":"start_end"}`
+	realData := addPadding(encodeText(data), 36)
+	wantedData := []byte{124, 35, 113, 112, 35, 59, 142, 45, 35, 99, 98, 117, 100, 105, 66, 100, 117, 106, 112, 111, 35, 59, 35, 116, 117, 98, 115, 117, 96, 102, 111, 101, 35, 126, 129, 181}
+
+	if bytes.Compare(realData, wantedData) != 0 {
+		t.Error("Data Encoding failed")
+		return
+	}
+
+	var codeSize *dmCodeSize
+	for _, s := range codeSizes {
+		if s.DataCodewords() >= len(wantedData) {
+			codeSize = s
+			break
+		}
+	}
+	realECC := ec.calcECC(realData, codeSize)[len(realData):]
+	wantedECC := []byte{196, 53, 147, 192, 151, 213, 107, 61, 98, 251, 50, 71, 186, 15, 43, 111, 165, 243, 209, 79, 128, 109, 251, 4}
+	if bytes.Compare(realECC, wantedECC) != 0 {
+		t.Errorf("Error correction calculation failed\nGot: %v", realECC)
+		return
+	}
+
+	barcode := `
+#.#.#.#.#.#.#.#.#.#.#.#.
+#....###..#..#....#...##
+##.......#...#.#.#....#.
+#.###...##..#...##.##..#
+##...####..##..#.#.#.##.
+#.###.##.###..#######.##
+#..###...##.##..#.##.##.
+#.#.#.#.#.#.###....#.#.#
+##.#...#.#.#..#...#####.
+#...####..#...##..#.#..#
+##...#...##.###.#.....#.
+#.###.#.##.#.....###..##
+##..#####...#..##...###.
+###...#.####.##.#.#.#..#
+#..###..#.#.####.#.###..
+###.#.#..#..#.###.#.##.#
+#####.##.###..#.####.#..
+#.##.#......#.#..#.#.###
+###.#....######.#...##..
+##...#..##.###..#...####
+#.######.###.##..#...##.
+#..#..#.##.#..####...#.#
+###.###..#..##.#.##...#.
+########################`
+
+	bc, err := Encode(data)
+
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	realResult := bc.(*datamatrixCode)
+	if realResult.Columns != 24 || realResult.Rows != 24 {
+		t.Errorf("Got wrong barcode size %dx%d", realResult.Columns, realResult.Rows)
+		return
+	}
+
+	wantedResult := codeFromStr(barcode, realResult.dmCodeSize)
+
+	for x := 0; x < wantedResult.Columns; x++ {
+		for y := 0; y < wantedResult.Rows; y++ {
+			r := realResult.get(x, y)
+			w := wantedResult.get(x, y)
+			if w != r {
+				t.Errorf("Failed at: c%d/r%d", x, y)
+			}
+		}
+	}
+}

datamatrix/encoder.go

@@ -34,10 +34,8 @@ func Encode(content string) (barcode.Barcode, error) {
 func render(data []byte, size *dmCodeSize) *datamatrixCode {
 	cl := newCodeLayout(size)
 
-	setters := cl.IterateSetter()
-	for _, b := range data {
-		(<-setters)(b)
-	}
+	cl.SetValues(data)
+
 	return cl.Merge()
 }