1 files changed, 194 insertions, 0 deletions
diff --git a/weed/data/read_test.go b/weed/data/read_test.go
new file mode 100644
index 000000000..83742d675
--- /dev/null
+++ b/weed/data/read_test.go
@@ -0,0 +1,194 @@
+package data
+
+import (
+	"encoding/binary"
+	"fmt"
+	"github.com/seaweedfs/seaweedfs/weed/util"
+	"io"
+	"testing"
+)
+
+func TestRead(t *testing.T) {
+	x := make([]uint16, 128)
+	y := make([]uint32, 128)
+
+	for i := range x {
+		x[i] = uint16(i)
+	}
+	for i := range y {
+		y[i] = uint32(i * 32)
+	}
+
+	xbuf := make([]byte, len(x)*SIZE_Uint16)
+	ybuf := make([]byte, len(x)*SIZE_Uint32)
+
+	WriteUint16s(xbuf, x)
+	WriteUint32s(ybuf, y)
+
+	df := &DataFile{
+		xbuf:      xbuf,
+		ybuf:      ybuf,
+		xLen:      len(xbuf),
+		yLen:      len(ybuf),
+		xReaderAt: util.NewBytesReader(xbuf),
+		yReaderAt: util.NewBytesReader(ybuf),
+	}
+
+	dataLayout := make(map[FieldName]DataLayout)
+	dataLayout["x"] = DataLayout{
+		LayoutType: Uint16,
+		SortType:   Unsorted,
+	}
+	dataLayout["y"] = DataLayout{
+		LayoutType: Uint32,
+		SortType:   Unsorted,
+	}
+
+	rows, err := df.ReadRows("x", dataLayout, Equal, NewDUint16(65))
+	if err != nil {
+		fmt.Printf("err: %v", err)
+		return
+	}
+	for _, row := range rows {
+		fmt.Printf("row %d width %d ", row.index, len(row.Datums))
+		for i, d := range row.Datums {
+			fmt.Printf("%d: %v ", i, d)
+		}
+		fmt.Println()
+	}
+
+}
+
+type Operator int32
+type LayoutType int32
+type SortType int32
+
+const (
+	Equal Operator = 0
+	GreaterThan
+	GreaterOrEqual
+	LessThan
+	LessOrEqual
+
+	Uint16 LayoutType = 0
+	Uint32            = 1
+
+	Unsorted SortType = 0
+	Ascending
+	Descending
+)
+
+type DataFile struct {
+	xbuf      []byte
+	ybuf      []byte
+	xReaderAt io.ReaderAt
+	xLen      int
+	yReaderAt io.ReaderAt
+	yLen      int
+}
+
+type DataLayout struct {
+	LayoutType
+	SortType
+}
+
+type FieldName string
+
+func (d *DataFile) ReadRows(field FieldName, layout map[FieldName]DataLayout, op Operator, operand Datum) (rows []*Row, err error) {
+	if field == "x" {
+		rows, err = pushDownReadRows(d.xReaderAt, d.xLen, layout[field], op, operand)
+		if err != nil {
+			return
+		}
+		err = hydrateRows(d.yReaderAt, d.yLen, layout["y"], rows)
+	}
+	if field == "y" {
+		rows, err = pushDownReadRows(d.yReaderAt, d.yLen, layout[field], op, operand)
+		if err != nil {
+			return
+		}
+		err = hydrateRows(d.xReaderAt, d.xLen, layout["x"], rows)
+	}
+	return
+}
+
+type Row struct {
+	index int
+	Datums
+}
+
+func pushDownReadRows(readerAt io.ReaderAt, dataLen int, layout DataLayout, op Operator, operand Datum) (rows []*Row, err error) {
+	if layout.LayoutType == Uint16 {
+		if layout.SortType == Unsorted {
+			buf := make([]byte, SIZE_Uint16)
+			for i := 0; i < dataLen; i += SIZE_Uint16 {
+				if n, err := readerAt.ReadAt(buf, int64(i)); n == SIZE_Uint16 && err == nil {
+					d := NewDUint16(DUint16(binary.BigEndian.Uint16(buf)))
+					cmp, err := d.Compare(operand)
+					if err != nil {
+						return rows, err
+					}
+					if cmp == 0 && op == Equal {
+						println(1)
+						rows = append(rows, &Row{
+							index:  i / SIZE_Uint16,
+							Datums: []Datum{d},
+						})
+					}
+				}
+			}
+		}
+	}
+	if layout.LayoutType == Uint32 {
+		if layout.SortType == Unsorted {
+			buf := make([]byte, SIZE_Uint32)
+			for i := 0; i < dataLen; i += SIZE_Uint32 {
+				if n, err := readerAt.ReadAt(buf, int64(i)); n == SIZE_Uint32 && err == nil {
+					d := NewDUint32(DUint32(binary.BigEndian.Uint32(buf)))
+					cmp, err := d.Compare(operand)
+					if err != nil {
+						return rows, err
+					}
+					if cmp == 0 && op == Equal {
+						println(2)
+						rows = append(rows, &Row{
+							index:  i / SIZE_Uint32,
+							Datums: []Datum{d},
+						})
+					}
+				}
+			}
+		}
+	}
+	return
+}
+
+func hydrateRows(readerAt io.ReaderAt, dataLen int, layout DataLayout, rows []*Row) (err error) {
+	if layout.LayoutType == Uint16 {
+		if layout.SortType == Unsorted {
+			buf := make([]byte, SIZE_Uint16)
+			for _, row := range rows {
+				if n, err := readerAt.ReadAt(buf, int64(row.index)*SIZE_Uint16); n == SIZE_Uint16 && err == nil {
+					t := binary.BigEndian.Uint16(buf)
+					d := NewDUint16(DUint16(t))
+					println(3, "add", t)
+					row.Datums = append(row.Datums, d)
+				}
+			}
+		}
+	}
+	if layout.LayoutType == Uint32 {
+		if layout.SortType == Unsorted {
+			buf := make([]byte, SIZE_Uint32)
+			for _, row := range rows {
+				if n, err := readerAt.ReadAt(buf, int64(row.index)*SIZE_Uint32); n == SIZE_Uint32 && err == nil {
+					t := binary.BigEndian.Uint32(buf)
+					d := NewDUint32(DUint32(t))
+					println(4, "add", t)
+					row.Datums = append(row.Datums, d)
+				}
+			}
+		}
+	}
+	return
+}