wehub-resource-sync
50 lines
1.5 KiB
Go
50 lines
1.5 KiB
Go
// Copyright 2024 Dolthub, 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 functions
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import (
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"github.com/cockroachdb/apd/v3"
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"github.com/cockroachdb/errors"
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"github.com/dolthub/go-mysql-server/sql"
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"github.com/dolthub/doltgresql/server/functions/framework"
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pgtypes "github.com/dolthub/doltgresql/server/types"
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)
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// initFactorial registers the functions to the catalog.
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func initFactorial() {
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framework.RegisterFunction(factorial_int64)
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}
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// factorial_int64 represents the PostgreSQL function of the same name, taking the same parameters.
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var factorial_int64 = framework.Function1{
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Name: "factorial",
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Return: pgtypes.Numeric,
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Parameters: [1]*pgtypes.DoltgresType{pgtypes.Int64},
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Strict: true,
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Callable: func(ctx *sql.Context, _ [2]*pgtypes.DoltgresType, val any) (any, error) {
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n := val.(int64)
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if n < 0 {
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return nil, errors.Errorf("factorial of a negative number is undefined")
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}
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total := int64(1)
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for i := int64(2); i <= n; i++ {
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total *= i
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}
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return apd.New(total, 0), nil
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},
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}
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