/
mod.go
87 lines (70 loc) · 2.02 KB
/
mod.go
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 function
import (
"context"
)
import (
"github.com/pkg/errors"
"github.com/shopspring/decimal"
)
import (
"github.com/arana-db/arana/pkg/proto"
)
// FuncMod is https://dev.mysql.com/doc/refman/5.6/en/mathematical-functions.html#function_mod
const FuncMod = "MOD"
var _ proto.Func = (*modFunc)(nil)
func init() {
proto.RegisterFunc(FuncMod, modFunc{})
}
type modFunc struct{}
func (a modFunc) Apply(ctx context.Context, inputs ...proto.Valuer) (proto.Value, error) {
val1, err := inputs[0].Value(ctx)
if err != nil {
return nil, errors.Wrapf(err, "cannot eval %s", FuncMod)
}
val2, err := inputs[1].Value(ctx)
if err != nil {
return nil, errors.Wrapf(err, "cannot eval %s", FuncMod)
}
if val1 == nil || val2 == nil {
return nil, nil
}
x, err := val1.Decimal()
if err != nil {
x = decimal.Zero
}
y, err := val2.Decimal()
if err != nil {
return nil, nil
}
if y.IsZero() {
return nil, nil
}
z := x.Mod(y)
switch val1.Family() {
case proto.ValueFamilySign, proto.ValueFamilyUnsigned:
switch val2.Family() {
case proto.ValueFamilySign, proto.ValueFamilyUnsigned:
return proto.NewValueInt64(z.IntPart()), nil
}
}
return proto.NewValueDecimal(z), nil
}
func (a modFunc) NumInput() int {
return 2
}