tidb util 代码
文件路径：/util/schemacmp/util.go
/ Copyright 2022 PingCAP, Inc.
/
/ Licensed under the Apache License, Version 2.0 (the "License");
/ you may not use this file except in compliance with the License.
/ You may obtain a copy of the License at
/
/ http://www.apache.org/licenses/LICENSE-2.0
/
/ Unless required by applicable law or agreed to in writing, software
/ distributed under the License is distributed on an "AS IS" BASIS,
/ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/ See the License for the specific language governing permissions and
/ limitations under the License.
package schemacmp
import "github.com/pingcap/tidb/parser/mysql"
/ compareMySQLIntegerType compares two MySQL integer types,
/ return -1 if a < b, 0 if a == b and 1 if a > b.
func compareMySQLIntegerType(a, b byte) int {
if a == b {
return 0
}
/ TypeTiny(1) < TypeShort(2) < TypeInt24(9) < TypeLong(3) < TypeLonglong(8)
switch {
case a == mysql.TypeInt24:
if b <= mysql.TypeShort {
return 1
}
return -1
case b == mysql.TypeInt24:
if a <= mysql.TypeShort {
return -1
}
return 1
case a < b:
return -1
default:
return 1
}
}
/ compareMySQLBlobType compares two MySQL blob types,
/ return -1 if a < b, 0 if a == b and 1 if a > b.
func compareMySQLBlobType(a, b byte) int {
if a == b {
return 0
}
/ TypeTinyBlob(0xf9, 249) < TypeBlob(0xfc, 252) < TypeMediumBlob(0xfa, 250) < TypeLongBlob(0xfb, 251)
switch {
case a == mysql.TypeBlob:
if b == mysql.TypeTinyBlob {
return 1
}
return -1
case b == mysql.TypeBlob:
if a == mysql.TypeTinyBlob {
return -1
}
return 1
case a < b:
return -1
default:
return 1
}
}