70 lines
2.0 KiB
Go
70 lines
2.0 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package codec
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import (
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"github.com/pingcap/errors"
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"github.com/pingcap/failpoint"
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"github.com/pingcap/tidb/parser/mysql"
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"github.com/pingcap/tidb/types"
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)
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// EncodeDecimal encodes a decimal into a byte slice which can be sorted lexicographically later.
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func EncodeDecimal(b []byte, dec *types.MyDecimal, precision, frac int) ([]byte, error) {
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if precision == 0 {
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precision, frac = dec.PrecisionAndFrac()
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}
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if frac > mysql.MaxDecimalScale {
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frac = mysql.MaxDecimalScale
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}
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b = append(b, byte(precision), byte(frac))
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b, err := dec.WriteBin(precision, frac, b)
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return b, errors.Trace(err)
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}
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func valueSizeOfDecimal(dec *types.MyDecimal, precision, frac int) (int, error) {
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if precision == 0 {
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precision, frac = dec.PrecisionAndFrac()
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}
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binSize, err := types.DecimalBinSize(precision, frac)
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if err != nil {
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return 0, err
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}
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return binSize + 2, nil
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}
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// DecodeDecimal decodes bytes to decimal.
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func DecodeDecimal(b []byte) ([]byte, *types.MyDecimal, int, int, error) {
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failpoint.Inject("errorInDecodeDecimal", func(val failpoint.Value) {
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if val.(bool) {
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failpoint.Return(b, nil, 0, 0, errors.New("gofail error"))
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}
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})
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if len(b) < 3 {
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return b, nil, 0, 0, errors.New("insufficient bytes to decode value")
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}
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precision := int(b[0])
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frac := int(b[1])
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b = b[2:]
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dec := new(types.MyDecimal)
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binSize, err := dec.FromBin(b, precision, frac)
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b = b[binSize:]
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if err != nil {
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return b, nil, precision, frac, errors.Trace(err)
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}
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return b, dec, precision, frac, nil
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}
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