gitea/vendor/github.com/pingcap/tidb/evaluator/builtin_math.go

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// Copyright 2013 The ql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSES/QL-LICENSE file.
// 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 evaluator
import (
"math"
"math/rand"
"github.com/juju/errors"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/util/types"
)
// see https://dev.mysql.com/doc/refman/5.7/en/mathematical-functions.html
func builtinAbs(args []types.Datum, _ context.Context) (d types.Datum, err error) {
d = args[0]
switch d.Kind() {
case types.KindNull:
return d, nil
case types.KindUint64:
return d, nil
case types.KindInt64:
iv := d.GetInt64()
if iv >= 0 {
d.SetInt64(iv)
return d, nil
}
d.SetInt64(-iv)
return d, nil
default:
// we will try to convert other types to float
// TODO: if time has no precision, it will be a integer
f, err := d.ToFloat64()
d.SetFloat64(math.Abs(f))
return d, errors.Trace(err)
}
}
func builtinRand(args []types.Datum, _ context.Context) (d types.Datum, err error) {
if len(args) == 1 && args[0].Kind() != types.KindNull {
seed, err := args[0].ToInt64()
if err != nil {
d.SetNull()
return d, errors.Trace(err)
}
rand.Seed(seed)
}
d.SetFloat64(rand.Float64())
return d, nil
}
func builtinPow(args []types.Datum, _ context.Context) (d types.Datum, err error) {
x, err := args[0].ToFloat64()
if err != nil {
d.SetNull()
return d, errors.Trace(err)
}
y, err := args[1].ToFloat64()
if err != nil {
d.SetNull()
return d, errors.Trace(err)
}
d.SetFloat64(math.Pow(x, y))
return d, nil
}