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Merge pull request #1019 from pingcap/coocood/fix-decimal-codec

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util/codec: fix decimal encoding.
This commit is contained in:
Ewan Chou
2016-03-28 20:00:23 +08:00
parent 1d35814e89 38f77b979c
commit 4e9ebe5636
2 changed files with 11 additions and 11 deletions
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1
util/codec/codec_test.go
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@ -608,6 +608,7 @@ func (s *testCodecSuite) TestDecimal(c *C) {
{"0", "-0.0000", 0},
{"-0.0001", "0", -1},
{"-0.1234", "0", -1},
{"-0.1234", "-0.12", -1},
{"-0.1234", "0.1234", -1},
{"-1.234", "-12.34", 1},
{"-0.1234", "-12.34", 1},

21
util/codec/decimal.go
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@ -59,12 +59,6 @@ func decodeExp(expValue int64, expSign int64, valSign int64) int64 {
return expValue
}
func codecValue(value []byte, valSign int64) {
if valSign == negativeSign {
reverseBytes(value)
}
}
// EncodeDecimal encodes a decimal d into a byte slice which can be sorted lexicographically later.
// EncodeDecimal guarantees that the encoded value is in ascending order for comparison.
// Decimal encoding:
@ -106,14 +100,16 @@ func EncodeDecimal(b []byte, d mysql.Decimal) []byte {
expSign := codecSign(expVal)
// For negtive exp, do bit reverse for exp.
// For negtive decimal, do bit reverse for exp and value.
expVal = encodeExp(expVal, expSign, valSign)
codecValue(value, valSign)
b = append(b, byte(valSign))
b = append(b, byte(expSign))
b = EncodeInt(b, expVal)
b = EncodeBytes(b, value)
if valSign == negativeSign {
b = EncodeBytesDesc(b, value)
} else {
b = EncodeBytes(b, value)
}
return b
}
@ -153,11 +149,14 @@ func DecodeDecimal(b []byte) ([]byte, mysql.Decimal, error) {
// Decode abs value bytes.
value := []byte{}
r, value, err = DecodeBytes(r)
if valSign == negativeSign {
r, value, err = DecodeBytesDesc(r)
} else {
r, value, err = DecodeBytes(r)
}
if err != nil {
return r, d, errors.Trace(err)
}
codecValue(value, valSign)
// Generate decimal string value.
var decimalStr []byte