mirror of https://github.com/tikv/client-go.git
89 lines
2.5 KiB
Go
89 lines
2.5 KiB
Go
// Copyright 2021 TiKV Authors
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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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// NOTE: The code in this file is based on code from the
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// TiDB project, licensed under the Apache License v 2.0
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//
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// https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/kv/key.go
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//
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// Copyright 2021 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 kv
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import (
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"bytes"
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)
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// NextKey returns the next key in byte-order.
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func NextKey(k []byte) []byte {
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// add 0x0 to the end of key
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buf := make([]byte, len(k)+1)
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copy(buf, k)
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return buf
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}
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// PrefixNextKey returns the next prefix key.
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//
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// Assume there are keys like:
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//
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// rowkey1
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// rowkey1_column1
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// rowkey1_column2
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// rowKey2
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//
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// If we seek 'rowkey1' NextKey, we will get 'rowkey1_column1'.
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// If we seek 'rowkey1' PrefixNextKey, we will get 'rowkey2'.
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func PrefixNextKey(k []byte) []byte {
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buf := make([]byte, len(k))
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copy(buf, k)
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var i int
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for i = len(k) - 1; i >= 0; i-- {
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buf[i]++
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if buf[i] != 0 {
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break
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}
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}
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if i == -1 {
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// Unlike TiDB, for the specific key 0xFF
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// we return empty slice instead of {0xFF, 0x0}
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buf = make([]byte, 0)
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}
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return buf
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}
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// CmpKey returns the comparison result of two key.
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// The result will be 0 if a==b, -1 if a < b, and +1 if a > b.
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func CmpKey(k, another []byte) int {
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return bytes.Compare(k, another)
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}
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// KeyRange represents a range where StartKey <= key < EndKey.
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type KeyRange struct {
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StartKey []byte
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EndKey []byte
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}
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