// DecodeDecimal decodes bytes to decimal. func DecodeDecimal(b []byte) ([]byte, types.Datum, error) { var d types.Datum if len(b) < 3 { return b, d, errors.New("insufficient bytes to decode value") } precision := int(b[0]) frac := int(b[1]) b = b[2:] dec := new(mysql.MyDecimal) binSize, err := dec.FromBin(b, precision, frac) b = b[binSize:] if err != nil { return b, d, errors.Trace(err) } d.SetLength(precision) d.SetFrac(frac) d.SetMysqlDecimal(dec) return b, d, nil }
func (s *testCodecSuite) TestDecimal(c *C) { defer testleak.AfterTest(c)() tbl := []string{ "1234.00", "1234", "12.34", "12.340", "0.1234", "0.0", "0", "-0.0", "-0.0000", "-1234.00", "-1234", "-12.34", "-12.340", "-0.1234", } for _, t := range tbl { dec := new(mysql.MyDecimal) err := dec.FromString([]byte(t)) c.Assert(err, IsNil) b, err := EncodeKey(nil, types.NewDatum(dec)) c.Assert(err, IsNil) v, err := Decode(b) c.Assert(err, IsNil) c.Assert(v, HasLen, 1) vv := v[0].GetMysqlDecimal() c.Assert(vv.Compare(dec), Equals, 0) } tblCmp := []struct { Arg1 interface{} Arg2 interface{} Ret int }{ // Test for float type decimal. {"1234", "123400", -1}, {"12340", "123400", -1}, {"1234", "1234.5", -1}, {"1234", "1234.0000", 0}, {"1234", "12.34", 1}, {"12.34", "12.35", -1}, {"0.12", "0.1234", -1}, {"0.1234", "12.3400", -1}, {"0.1234", "0.1235", -1}, {"0.123400", "12.34", -1}, {"12.34000", "12.34", 0}, {"0.01234", "0.01235", -1}, {"0.1234", "0", 1}, {"0.0000", "0", 0}, {"0.0001", "0", 1}, {"0.0001", "0.0000", 1}, {"0", "-0.0000", 0}, {"-0.0001", "0", -1}, {"-0.1234", "0", -1}, {"-0.1234", "-0.12", -1}, {"-0.12", "-0.1234", 1}, {"-0.12", "-0.1200", 0}, {"-0.1234", "0.1234", -1}, {"-1.234", "-12.34", 1}, {"-0.1234", "-12.34", 1}, {"-12.34", "1234", -1}, {"-12.34", "-12.35", 1}, {"-0.01234", "-0.01235", 1}, {"-1234", "-123400", 1}, {"-12340", "-123400", 1}, // Test for int type decimal. {int64(-1), int64(1), -1}, {int64(math.MaxInt64), int64(math.MinInt64), 1}, {int64(math.MaxInt64), int64(math.MaxInt32), 1}, {int64(math.MinInt32), int64(math.MaxInt16), -1}, {int64(math.MinInt64), int64(math.MaxInt8), -1}, {int64(0), int64(math.MaxInt8), -1}, {int64(math.MinInt8), int64(0), -1}, {int64(math.MinInt16), int64(math.MaxInt16), -1}, {int64(1), int64(-1), 1}, {int64(1), int64(0), 1}, {int64(-1), int64(0), -1}, {int64(0), int64(0), 0}, {int64(math.MaxInt16), int64(math.MaxInt16), 0}, // Test for uint type decimal. {uint64(0), uint64(0), 0}, {uint64(1), uint64(0), 1}, {uint64(0), uint64(1), -1}, {uint64(math.MaxInt8), uint64(math.MaxInt16), -1}, {uint64(math.MaxUint32), uint64(math.MaxInt32), 1}, {uint64(math.MaxUint8), uint64(math.MaxInt8), 1}, {uint64(math.MaxUint16), uint64(math.MaxInt32), -1}, {uint64(math.MaxUint64), uint64(math.MaxInt64), 1}, {uint64(math.MaxInt64), uint64(math.MaxUint32), 1}, {uint64(math.MaxUint64), uint64(0), 1}, {uint64(0), uint64(math.MaxUint64), -1}, } for _, t := range tblCmp { d1 := types.NewDatum(t.Arg1) dec1, err := d1.ToDecimal() c.Assert(err, IsNil) d1.SetMysqlDecimal(dec1) d2 := types.NewDatum(t.Arg2) dec2, err := d2.ToDecimal() c.Assert(err, IsNil) d2.SetMysqlDecimal(dec2) d1.SetLength(30) d1.SetFrac(6) d2.SetLength(30) d2.SetFrac(6) b1, err := EncodeKey(nil, d1) c.Assert(err, IsNil) b2, err := EncodeKey(nil, d2) c.Assert(err, IsNil) ret := bytes.Compare(b1, b2) c.Assert(ret, Equals, t.Ret, Commentf("%v %x %x", t, b1, b2)) } floats := []float64{-123.45, -123.40, -23.45, -1.43, -0.93, -0.4333, -0.068, -0.0099, 0, 0.001, 0.0012, 0.12, 1.2, 1.23, 123.3, 2424.242424} var decs [][]byte for i := range floats { dec := mysql.NewDecFromFloatForTest(floats[i]) var d types.Datum d.SetLength(20) d.SetFrac(6) d.SetMysqlDecimal(dec) decs = append(decs, EncodeDecimal(nil, d)) } for i := 0; i < len(decs)-1; i++ { cmp := bytes.Compare(decs[i], decs[i+1]) c.Assert(cmp, LessEqual, 0) } }