chore: import upstream snapshot with attribution

server/functions/width_bucket.go

@@ -0,0 +1,122 @@
+// 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 (
+	"math"
+
+	"github.com/cockroachdb/apd/v3"
+	"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"
+)
+
+// initWidthBucket registers the functions to the catalog.
+func initWidthBucket() {
+	framework.RegisterFunction(width_bucket_float64_float64_float64_int64)
+	framework.RegisterFunction(width_bucket_numeric_numeric_numeric_int64)
+}
+
+// width_bucket_float64_float64_float64_int64 represents the PostgreSQL function of the same name, taking the same parameters.
+var width_bucket_float64_float64_float64_int64 = framework.Function4{
+	Name:       "width_bucket",
+	Return:     pgtypes.Int32,
+	Parameters: [4]*pgtypes.DoltgresType{pgtypes.Float64, pgtypes.Float64, pgtypes.Float64, pgtypes.Int32},
+	Strict:     true,
+	Callable: func(ctx *sql.Context, _ [5]*pgtypes.DoltgresType, operandInterface any, lowInterface any, highInterface any, countInterface any) (any, error) {
+		operand := operandInterface.(float64)
+		low := lowInterface.(float64)
+		high := highInterface.(float64)
+		if low == high {
+			return nil, errors.Errorf("lower bound cannot equal upper bound")
+		}
+		count := countInterface.(int32)
+		if count <= 0 {
+			return nil, errors.Errorf("count must be greater than zero")
+		}
+		if operand == high {
+			return count + 1, nil
+		} else if operand == low {
+			return int32(1), nil
+		}
+		bucket := (high - low) / float64(count)
+		result := math.Ceil((operand - low) / bucket)
+		if result < 0 {
+			result = 0
+		} else if result > float64(count+1) {
+			result = float64(count + 1)
+		}
+		return int32(result), nil
+	},
+}
+
+// width_bucket_numeric_numeric_numeric_int64 represents the PostgreSQL function of the same name, taking the same parameters.
+var width_bucket_numeric_numeric_numeric_int64 = framework.Function4{
+	Name:       "width_bucket",
+	Return:     pgtypes.Int32,
+	Parameters: [4]*pgtypes.DoltgresType{pgtypes.Numeric, pgtypes.Numeric, pgtypes.Numeric, pgtypes.Int32},
+	Strict:     true,
+	Callable: func(ctx *sql.Context, _ [5]*pgtypes.DoltgresType, operandInterface any, lowInterface any, highInterface any, countInterface any) (any, error) {
+		operand := operandInterface.(*apd.Decimal)
+		low := lowInterface.(*apd.Decimal)
+		high := highInterface.(*apd.Decimal)
+		if low.Cmp(high) == 0 {
+			return nil, errors.Errorf("lower bound cannot equal upper bound")
+		}
+		count := countInterface.(int32)
+		if count <= 0 {
+			return nil, errors.Errorf("count must be greater than zero")
+		}
+		if operand.Cmp(high) == 0 {
+			return count + 1, nil
+		} else if operand.Cmp(low) == 0 {
+			return int32(1), nil
+		}
+		bucket := new(apd.Decimal)
+		_, err := sql.DecimalCtx.Sub(bucket, high, low)
+		if err != nil {
+			return nil, err
+		}
+		_, err = sql.DecimalCtx.Quo(bucket, bucket, apd.New(int64(count), 0))
+		if err != nil {
+			return nil, err
+		}
+		result := new(apd.Decimal)
+		_, err = sql.DecimalCtx.Sub(result, operand, low)
+		if err != nil {
+			return nil, err
+		}
+		_, err = sql.DecimalCtx.Sub(result, result, bucket)
+		if err != nil {
+			return nil, err
+		}
+		_, err = sql.DecimalCtx.Ceil(result, result)
+		if err != nil {
+			return nil, err
+		}
+		if result.Sign() < 0 {
+			result = apd.New(0, 0)
+		} else if c1 := apd.New(int64(count+1), 0); result.Cmp(c1) > 0 {
+			result = c1
+		}
+		i64, err := result.Int64()
+		if err != nil {
+			return nil, err
+		}
+		return int32(i64), nil
+	},
+}