chore: import upstream snapshot with attribution

server/functions/div.go

@@ -0,0 +1,69 @@
+// Copyright 2024 Dolthub, 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 functions
+
+import (
+	"github.com/cockroachdb/apd/v3"
+	errors "github.com/cockroachdb/errors"
+	"github.com/dolthub/go-mysql-server/sql"
+
+	"github.com/dolthub/doltgresql/server/functions/framework"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+)
+
+// initDiv registers the functions to the catalog.
+func initDiv() {
+	framework.RegisterFunction(div_numeric)
+}
+
+// div_numeric represents the PostgreSQL function of the same name, taking the same parameters.
+var div_numeric = framework.Function2{
+	Name:       "div",
+	Return:     pgtypes.Numeric,
+	Parameters: [2]*pgtypes.DoltgresType{pgtypes.Numeric, pgtypes.Numeric},
+	Strict:     true,
+	Callable: func(ctx *sql.Context, _ [3]*pgtypes.DoltgresType, val1 any, val2 any) (any, error) {
+		num1 := val1.(*apd.Decimal)
+		num2 := val2.(*apd.Decimal)
+		if num1.Form == apd.NaN || num2.Form == apd.NaN ||
+			(num1.Form == apd.Infinite && num2.Form == apd.Infinite) {
+			return pgtypes.NumericNaN, nil
+		}
+		if num2.IsZero() {
+			return nil, errors.Errorf("division by zero")
+		}
+		if num1.Form == apd.Infinite {
+			return num1, nil
+		}
+		if num2.Form == apd.Infinite {
+			return apd.New(0, 0), nil
+		}
+
+		p := num1.NumDigits()
+		if num1.Exponent > 0 {
+			p += int64(num1.Exponent)
+		}
+		if num2.Exponent < 0 {
+			p += int64(-num2.Exponent)
+		}
+
+		res := new(apd.Decimal)
+		_, err := sql.DecimalCtx.WithPrecision(uint32(p)).QuoInteger(res, num1, num2)
+		if err != nil {
+			return nil, err
+		}
+		return res, nil
+	},
+}