chore: import upstream snapshot with attribution

server/cast/float64.go

@@ -0,0 +1,89 @@
+// 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 cast
+
+import (
+	"math"
+
+	"github.com/cockroachdb/apd/v3"
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/go-mysql-server/sql"
+
+	"github.com/dolthub/doltgresql/core/casts"
+	"github.com/dolthub/doltgresql/core/id"
+	"github.com/dolthub/doltgresql/server/functions/framework"
+	pgtypes "github.com/dolthub/doltgresql/server/types"
+)
+
+// initFloat64 handles all casts that are built-in. This comprises only the source types.
+func initFloat64(builtInCasts map[id.Cast]casts.Cast) {
+	float64Assignment(builtInCasts)
+}
+
+// float64Assignment registers all assignment casts. This comprises only the source types.
+func float64Assignment(builtInCasts map[id.Cast]casts.Cast) {
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Float64,
+		ToType:   pgtypes.Float32,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			return float32(val.(float64)), nil
+		},
+	})
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Float64,
+		ToType:   pgtypes.Int16,
+		Function: func(ctx *sql.Context, valInterface any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			val := math.RoundToEven(valInterface.(float64))
+			if val > 32767 || val < -32768 {
+				return nil, errors.Wrap(pgtypes.ErrCastOutOfRange, "smallint out of range")
+			}
+			return int16(val), nil
+		},
+	})
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Float64,
+		ToType:   pgtypes.Int32,
+		Function: func(ctx *sql.Context, valInterface any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			val := math.RoundToEven(valInterface.(float64))
+			if val > 2147483647 || val < -2147483648 {
+				return nil, errors.Wrap(pgtypes.ErrCastOutOfRange, "integer out of range")
+			}
+			return int32(val), nil
+		},
+	})
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Float64,
+		ToType:   pgtypes.Int64,
+		Function: func(ctx *sql.Context, valInterface any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			val := math.RoundToEven(valInterface.(float64))
+			if val > 9223372036854775807 || val < -9223372036854775808 {
+				return nil, errors.Wrap(pgtypes.ErrCastOutOfRange, "bigint out of range")
+			}
+			return int64(val), nil
+		},
+	})
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Float64,
+		ToType:   pgtypes.Numeric,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			d := new(apd.Decimal)
+			err := d.Scan(val.(float64))
+			if err != nil {
+				return nil, err
+			}
+			return pgtypes.GetNumericValueWithTypmod(d, targetType.GetAttTypMod())
+		},
+	})
+}