96 lines
2.7 KiB
Go
96 lines
2.7 KiB
Go
// Copyright 2023 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 external
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import (
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"encoding/binary"
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)
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// rangeProperty stores properties of a range:
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// - key: the start key of the range.
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// - offset: the start offset of the range in the file.
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// - size: the size of the range.
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// - keys: the number of keys in the range.
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type rangeProperty struct {
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firstKey []byte
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lastKey []byte
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offset uint64
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size uint64
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keys uint64
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}
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// decodeMultiProps is only used for test.
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func decodeMultiProps(data []byte) []*rangeProperty {
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var ret []*rangeProperty
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for len(data) > 0 {
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propLen := int(binary.BigEndian.Uint32(data))
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propBytes := data[4 : 4+propLen]
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rp := decodeProp(propBytes)
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ret = append(ret, rp)
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data = data[4+propLen:]
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}
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return ret
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}
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func decodeProp(data []byte) *rangeProperty {
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rp := &rangeProperty{}
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n := 0
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keyLen := int(binary.BigEndian.Uint32(data[n : n+4]))
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n += 4
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rp.firstKey = data[n : n+keyLen]
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n += keyLen
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keyLen = int(binary.BigEndian.Uint32(data[n : n+4]))
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n += 4
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rp.lastKey = data[n : n+keyLen]
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n += keyLen
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rp.size = binary.BigEndian.Uint64(data[n : n+8])
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n += 8
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rp.keys = binary.BigEndian.Uint64(data[n : n+8])
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n += 8
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rp.offset = binary.BigEndian.Uint64(data[n : n+8])
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return rp
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}
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// keyLen * 2 + p.size + p.keys + p.offset
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const propertyLengthExceptKeys = 4*2 + 8 + 8 + 8
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func encodeMultiProps(buf []byte, props []*rangeProperty) []byte {
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var propLen [4]byte
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for _, p := range props {
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binary.BigEndian.PutUint32(propLen[:],
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uint32(propertyLengthExceptKeys+len(p.firstKey)+len(p.lastKey)))
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buf = append(buf, propLen[:4]...)
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buf = encodeProp(buf, p)
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}
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return buf
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}
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func encodeProp(buf []byte, r *rangeProperty) []byte {
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var b [8]byte
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binary.BigEndian.PutUint32(b[:], uint32(len(r.firstKey)))
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buf = append(buf, b[:4]...)
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buf = append(buf, r.firstKey...)
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binary.BigEndian.PutUint32(b[:], uint32(len(r.lastKey)))
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buf = append(buf, b[:4]...)
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buf = append(buf, r.lastKey...)
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binary.BigEndian.PutUint64(b[:], r.size)
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buf = append(buf, b[:]...)
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binary.BigEndian.PutUint64(b[:], r.keys)
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buf = append(buf, b[:]...)
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binary.BigEndian.PutUint64(b[:], r.offset)
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buf = append(buf, b[:]...)
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return buf
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}
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