refactor: chunk -> share (#306)

Closes #215

codec_test.go

@@ -34,10 +34,10 @@ func BenchmarkEncoding(b *testing.B) {
 	}
 }
 
-func generateRandData(count int, chunkSize int) [][]byte {
+func generateRandData(count int, shareSize int) [][]byte {
 	out := make([][]byte, count)
 	for i := 0; i < count; i++ {
-		randData := make([]byte, chunkSize)
+		randData := make([]byte, shareSize)
 		_, err := cryptorand.Read(randData)
 		if err != nil {
 			panic(err)
@@ -70,8 +70,8 @@ func BenchmarkDecoding(b *testing.B) {
 	}
 }
 
-func generateMissingData(count int, chunkSize int, codec Codec) [][]byte {
-	randData := generateRandData(count, chunkSize)
+func generateMissingData(count int, shareSize int, codec Codec) [][]byte {
+	randData := generateRandData(count, shareSize)
 	encoded, err := codec.Encode(randData)
 	if err != nil {
 		panic(err)
@@ -98,12 +98,12 @@ func newTestCodec() Codec {
 	return &testCodec{}
 }
 
-func (c *testCodec) Encode(chunk [][]byte) ([][]byte, error) {
-	return chunk, nil
+func (c *testCodec) Encode(share [][]byte) ([][]byte, error) {
+	return share, nil
 }
 
-func (c *testCodec) Decode(chunk [][]byte) ([][]byte, error) {
-	return chunk, nil
+func (c *testCodec) Decode(share [][]byte) ([][]byte, error) {
+	return share, nil
 }
 
 func (c *testCodec) MaxChunks() int {

codecs.go

@@ -6,8 +6,8 @@ const (
 	// Leopard is a codec that was originally implemented in the C++ library
 	// https://github.com/catid/leopard. rsmt2d uses a Go port of the C++
 	// library in https://github.com/klauspost/reedsolomon. The Leopard codec
-	// uses 8-bit leopard for shards less than or equal to 256. The Leopard
-	// codec uses 16-bit leopard for shards greater than 256.
+	// uses 8-bit leopard for shares less than or equal to 256. The Leopard
+	// codec uses 16-bit leopard for shares greater than 256.
 	Leopard = "Leopard"
 )
 
@@ -19,12 +19,13 @@ type Codec interface {
 	// Missing shares must be nil. Returns original + parity data.
 	Decode(data [][]byte) ([][]byte, error)
 	// MaxChunks returns the max number of chunks this codec supports in a 2D
-	// original data square.
+	// original data square. Chunk is a synonym of share.
 	MaxChunks() int
 	// Name returns the name of the codec.
 	Name() string
 	// ValidateChunkSize returns an error if this codec does not support
-	// chunkSize. Returns nil if chunkSize is supported.
+	// chunkSize. Returns nil if chunkSize is supported. Chunk is a synonym of
+	// share.
 	ValidateChunkSize(chunkSize int) error
 }
 

datasquare.go

@@ -9,8 +9,9 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
-// ErrUnevenChunks is thrown when non-nil chunks are not all of equal size.
-var ErrUnevenChunks = errors.New("non-nil chunks not all of equal size")
+// ErrUnevenChunks is thrown when non-nil shares are not all of equal size.
+// Note: chunks is synonymous with shares.
+var ErrUnevenChunks = errors.New("non-nil shares not all of equal size")
 
 // dataSquare stores all data for an original data square (ODS) or extended
 // data square (EDS). Data is duplicated in both row-major and column-major
@@ -20,7 +21,7 @@ type dataSquare struct {
 	squareCol    [][][]byte // col-major
 	dataMutex    sync.Mutex
 	width        uint
-	chunkSize    uint
+	shareSize    uint
 	rowRoots     [][]byte
 	colRoots     [][]byte
 	createTreeFn TreeConstructorFn
@@ -29,14 +30,15 @@ type dataSquare struct {
 // newDataSquare populates the data square from the supplied data and treeCreator.
 // No root calculation is performed.
 // data may have nil values.
-func newDataSquare(data [][]byte, treeCreator TreeConstructorFn, chunkSize uint) (*dataSquare, error) {
+func newDataSquare(data [][]byte, treeCreator TreeConstructorFn, shareSize uint) (*dataSquare, error) {
 	width := int(math.Ceil(math.Sqrt(float64(len(data)))))
 	if width*width != len(data) {
+		// TODO: export this error and modify chunks to shares
 		return nil, errors.New("number of chunks must be a square number")
 	}
 
 	for _, d := range data {
-		if d != nil && len(d) != int(chunkSize) {
+		if d != nil && len(d) != int(shareSize) {
 			return nil, ErrUnevenChunks
 		}
 	}
@@ -46,7 +48,7 @@ func newDataSquare(data [][]byte, treeCreator TreeConstructorFn, chunkSize uint)
 		squareRow[i] = data[i*width : i*width+width]
 
 		for j := 0; j < width; j++ {
-			if squareRow[i][j] != nil && len(squareRow[i][j]) != int(chunkSize) {
+			if squareRow[i][j] != nil && len(squareRow[i][j]) != int(shareSize) {
 				return nil, ErrUnevenChunks
 			}
 		}
@@ -64,15 +66,16 @@ func newDataSquare(data [][]byte, treeCreator TreeConstructorFn, chunkSize uint)
 		squareRow:    squareRow,
 		squareCol:    squareCol,
 		width:        uint(width),
-		chunkSize:    chunkSize,
+		shareSize:    shareSize,
 		createTreeFn: treeCreator,
 	}, nil
 }
 
 // extendSquare extends the original data square by extendedWidth and fills
-// the extended quadrants with fillerChunk.
-func (ds *dataSquare) extendSquare(extendedWidth uint, fillerChunk []byte) error {
-	if uint(len(fillerChunk)) != ds.chunkSize {
+// the extended quadrants with fillerShare.
+func (ds *dataSquare) extendSquare(extendedWidth uint, fillerShare []byte) error {
+	if uint(len(fillerShare)) != ds.shareSize {
+		// TODO: export this error and rename chunk to share
 		return errors.New("filler chunk size does not match data square chunk size")
 	}
 
@@ -81,12 +84,12 @@ func (ds *dataSquare) extendSquare(extendedWidth uint, fillerChunk []byte) error
 
 	fillerExtendedRow := make([][]byte, extendedWidth)
 	for i := uint(0); i < extendedWidth; i++ {
-		fillerExtendedRow[i] = fillerChunk
+		fillerExtendedRow[i] = fillerShare
 	}
 
 	fillerRow := make([][]byte, newWidth)
 	for i := uint(0); i < newWidth; i++ {
-		fillerRow[i] = fillerChunk
+		fillerRow[i] = fillerShare
 	}
 
 	row := make([][]byte, ds.width)
@@ -129,7 +132,8 @@ func (ds *dataSquare) row(x uint) [][]byte {
 
 func (ds *dataSquare) setRowSlice(x uint, y uint, newRow [][]byte) error {
 	for i := uint(0); i < uint(len(newRow)); i++ {
-		if len(newRow[i]) != int(ds.chunkSize) {
+		if len(newRow[i]) != int(ds.shareSize) {
+			// TODO: export this error and rename chunk to share
 			return errors.New("invalid chunk size")
 		}
 	}
@@ -162,7 +166,8 @@ func (ds *dataSquare) col(y uint) [][]byte {
 
 func (ds *dataSquare) setColSlice(x uint, y uint, newCol [][]byte) error {
 	for i := uint(0); i < uint(len(newCol)); i++ {
-		if len(newCol[i]) != int(ds.chunkSize) {
+		if len(newCol[i]) != int(ds.shareSize) {
+			// TODO: export this error and rename chunk to share
 			return errors.New("invalid chunk size")
 		}
 	}
@@ -307,22 +312,23 @@ func (ds *dataSquare) GetCell(x uint, y uint) []byte {
 	if ds.squareRow[x][y] == nil {
 		return nil
 	}
-	cell := make([]byte, ds.chunkSize)
+	cell := make([]byte, ds.shareSize)
 	copy(cell, ds.squareRow[x][y])
 	return cell
 }
 
 // SetCell sets a specific cell. The cell to set must be `nil`. Returns an error
-// if the cell to set is not `nil` or newChunk is not the correct size.
-func (ds *dataSquare) SetCell(x uint, y uint, newChunk []byte) error {
+// if the cell to set is not `nil` or newShare is not the correct size.
+func (ds *dataSquare) SetCell(x uint, y uint, newShare []byte) error {
 	if ds.squareRow[x][y] != nil {
 		return fmt.Errorf("cannot set cell (%d, %d) as it already has a value %x", x, y, ds.squareRow[x][y])
 	}
-	if len(newChunk) != int(ds.chunkSize) {
-		return fmt.Errorf("cannot set cell with chunk size %d because dataSquare chunk size is %d", len(newChunk), ds.chunkSize)
+	if len(newShare) != int(ds.shareSize) {
+		// TODO: export this error and rename chunk to share
+		return fmt.Errorf("cannot set cell with chunk size %d because dataSquare chunk size is %d", len(newShare), ds.shareSize)
 	}
-	ds.squareRow[x][y] = newChunk
-	ds.squareCol[y][x] = newChunk
+	ds.squareRow[x][y] = newShare
+	ds.squareCol[y][x] = newShare
 	ds.resetRoots()
 	return nil
 }

datasquare_test.go

@@ -17,15 +17,15 @@ func TestNewDataSquare(t *testing.T) {
 		name      string
 		cells     [][]byte
 		expected  [][][]byte
-		chunkSize uint
+		shareSize uint
 	}{
 		{"1x1", [][]byte{{1, 2}}, [][][]byte{{{1, 2}}}, 2},
 		{"2x2", [][]byte{{1, 2}, {3, 4}, {5, 6}, {7, 8}}, [][][]byte{{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}}, 2},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			result, err := newDataSquare(test.cells, NewDefaultTree, test.chunkSize)
+			result, err := newDataSquare(test.cells, NewDefaultTree, test.shareSize)
 			if err != nil {
 				panic(err)
 			}
@@ -40,16 +40,16 @@ func TestInvalidDataSquareCreation(t *testing.T) {
 	tests := []struct {
 		name      string
 		cells     [][]byte
-		chunkSize uint
+		shareSize uint
 	}{
-		{"InconsistentChunkNumber", [][]byte{{1, 2}, {3, 4}, {5, 6}}, 2},
-		{"UnequalChunkSize", [][]byte{{1, 2}, {3, 4}, {5, 6}, {7}}, 2},
+		{"InconsistentShareNumber", [][]byte{{1, 2}, {3, 4}, {5, 6}}, 2},
+		{"UnequalShareSize", [][]byte{{1, 2}, {3, 4}, {5, 6}, {7}}, 2},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			_, err := newDataSquare(test.cells, NewDefaultTree, test.chunkSize)
+			_, err := newDataSquare(test.cells, NewDefaultTree, test.shareSize)
 			if err == nil {
-				t.Errorf("newDataSquare failed; chunks accepted with %v", test.name)
+				t.Errorf("newDataSquare failed; shares accepted with %v", test.name)
 			}
 		})
 	}
@@ -76,9 +76,9 @@ func TestSetCell(t *testing.T) {
 			wantErr:      true,
 		},
 		{
-			name:         "expect error if new cell is not the correct chunk size",
+			name:         "expect error if new cell is not the correct share size",
 			originalCell: nil,
-			newCell:      []byte{1, 2}, // incorrect chunk size
+			newCell:      []byte{1, 2}, // incorrect share size
 			wantErr:      true,
 		},
 	}
@@ -186,7 +186,7 @@ func TestInvalidSquareExtension(t *testing.T) {
 	}
 	err = ds.extendSquare(1, []byte{0})
 	if err == nil {
-		t.Errorf("extendSquare failed; error not returned when filler chunk size does not match data square chunk size")
+		t.Errorf("extendSquare failed; error not returned when filler share size does not match data square share size")
 	}
 }
 
@@ -318,7 +318,7 @@ func Test_setRowSlice(t *testing.T) {
 			wantErr: false,
 		},
 		{
-			name:    "returns an error if the new row has an invalid chunk size",
+			name:    "returns an error if the new row has an invalid share size",
 			newRow:  [][]byte{{5, 6}},
 			x:       0,
 			y:       0,
@@ -374,7 +374,7 @@ func Test_setColSlice(t *testing.T) {
 			wantErr: false,
 		},
 		{
-			name:    "returns an error if the new col has an invalid chunk size",
+			name:    "returns an error if the new col has an invalid share size",
 			newCol:  [][]byte{{5, 6}},
 			x:       0,
 			y:       0,
@@ -410,7 +410,7 @@ func BenchmarkEDSRootsWithDefaultTree(b *testing.B) {
 			b.Errorf("Failure to create square of size %d: %s", i, err)
 		}
 		b.Run(
-			fmt.Sprintf("%dx%dx%d ODS", i, i, int(square.chunkSize)),
+			fmt.Sprintf("%dx%dx%d ODS", i, i, int(square.shareSize)),
 			func(b *testing.B) {
 				for n := 0; n < b.N; n++ {
 					square.resetRoots()
@@ -458,7 +458,7 @@ func BenchmarkEDSRootsWithErasuredNMT(b *testing.B) {
 		edsSizeMiBytes := 4 * odsSizeMiBytes
 		b.Run(
 			fmt.Sprintf("%dx%dx%d ODS=%dMB, EDS=%dMB", odsSize, odsSize,
-				int(square.chunkSize),
+				int(square.shareSize),
 				odsSizeMiBytes, edsSizeMiBytes),
 			func(b *testing.B) {
 				for n := 0; n < b.N; n++ {
@@ -521,8 +521,8 @@ func (d *errorTree) Root() ([]byte, error) {
 // setCell overwrites the contents of a specific cell. setCell does not perform
 // any input validation so most use cases should use `SetCell` instead of
 // `setCell`. This method exists strictly for testing.
-func (ds *dataSquare) setCell(x uint, y uint, newChunk []byte) {
-	ds.squareRow[x][y] = newChunk
-	ds.squareCol[y][x] = newChunk
+func (ds *dataSquare) setCell(x uint, y uint, newShare []byte) {
+	ds.squareRow[x][y] = newShare
+	ds.squareCol[y][x] = newShare
 	ds.resetRoots()
 }

extendeddatacrossword.go

@@ -33,7 +33,7 @@ func (a Axis) String() string {
 	}
 }
 
-// ErrUnrepairableDataSquare is thrown when there is insufficient chunks to repair the square.
+// ErrUnrepairableDataSquare is thrown when there is insufficient shares to repair the square.
 var ErrUnrepairableDataSquare = errors.New("failed to solve data square")
 
 // ErrByzantineData is returned when a repaired row or column does not match the
@@ -380,7 +380,7 @@ func (eds *ExtendedDataSquare) preRepairSanityCheck(
 				if err != nil {
 					return err
 				}
-				if !bytes.Equal(flattenChunks(parityShares), flattenChunks(eds.rowSlice(i, eds.originalDataWidth, eds.originalDataWidth))) {
+				if !bytes.Equal(flattenShares(parityShares), flattenShares(eds.rowSlice(i, eds.originalDataWidth, eds.originalDataWidth))) {
 					return &ErrByzantineData{Row, i, eds.row(i)}
 				}
 				return nil
@@ -410,7 +410,7 @@ func (eds *ExtendedDataSquare) preRepairSanityCheck(
 				if err != nil {
 					return err
 				}
-				if !bytes.Equal(flattenChunks(parityShares), flattenChunks(eds.colSlice(eds.originalDataWidth, i, eds.originalDataWidth))) {
+				if !bytes.Equal(flattenShares(parityShares), flattenShares(eds.colSlice(eds.originalDataWidth, i, eds.originalDataWidth))) {
 					return &ErrByzantineData{Col, i, eds.col(i)}
 				}
 				return nil