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// Copyright 2015 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package types
import (
"strconv"
"strings"
"github.com/pingcap/errors"
)
var zeroSet = Set{Name: "", Value: 0}
// Set is for MySQL Set type.
type Set struct {
Name string
Value uint64
}
// String implements fmt.Stringer interface.
func (e Set) String() string {
return e.Name
}
// ToNumber changes Set to float64 for numeric operation.
func (e Set) ToNumber() float64 {
return float64(e.Value)
}
// ParseSetName creates a Set with name.
func ParseSetName(elems []string, name string) (Set, error) {
if len(name) == 0 {
return zeroSet, nil
}
seps := strings.Split(name, ",")
marked := make(map[string]struct{}, len(seps))
for _, s := range seps {
marked[strings.ToLower(s)] = struct{}{}
}
items := make([]string, 0, len(seps))
value := uint64(0)
for i, n := range elems {
key := strings.ToLower(n)
if _, ok := marked[key]; ok {
value |= 1 << uint64(i)
delete(marked, key)
items = append(items, n)
}
}
if len(marked) == 0 {
return Set{Name: strings.Join(items, ","), Value: value}, nil
}
// name doesn't exist, maybe an integer?
if num, err := strconv.ParseUint(name, 0, 64); err == nil {
return ParseSetValue(elems, num)
}
return Set{}, errors.Errorf("item %s is not in Set %v", name, elems)
}
var (
setIndexValue []uint64
setIndexInvertValue []uint64
)
func init() {
setIndexValue = make([]uint64, 64)
setIndexInvertValue = make([]uint64, 64)
for i := 0; i < 64; i++ {
setIndexValue[i] = 1 << uint64(i)
setIndexInvertValue[i] = ^setIndexValue[i]
}
}
// ParseSetValue creates a Set with special number.
func ParseSetValue(elems []string, number uint64) (Set, error) {
if number == 0 {
return zeroSet, nil
}
value := number
var items []string
for i := 0; i < len(elems); i++ {
if number&setIndexValue[i] > 0 {
items = append(items, elems[i])
number &= setIndexInvertValue[i]
}
}
if number != 0 {
return Set{}, errors.Errorf("invalid number %d for Set %v", number, elems)
}
return Set{Name: strings.Join(items, ","), Value: value}, nil
}
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