chore: import upstream snapshot with attribution

server/cast/numeric.go

@@ -0,0 +1,101 @@
+// 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 (
+	"github.com/cockroachdb/apd/v3"
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/types"
+
+	"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"
+)
+
+// initNumeric handles all casts that are built-in. This comprises only the source types.
+func initNumeric(builtInCasts map[id.Cast]casts.Cast) {
+	numericAssignment(builtInCasts)
+	numericImplicit(builtInCasts)
+}
+
+// numericAssignment registers all assignment casts. This comprises only the source types.
+func numericAssignment(builtInCasts map[id.Cast]casts.Cast) {
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Numeric,
+		ToType:   pgtypes.Int16,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			d := val.(*apd.Decimal)
+			if d.Cmp(pgtypes.NumericValueMinInt16) < 0 || d.Cmp(pgtypes.NumericValueMaxInt16) > 0 {
+				return nil, errors.Wrap(pgtypes.ErrCastOutOfRange, "smallint out of range")
+			}
+			i := types.DecimalRoundedIntPart(d)
+			return int16(i), nil
+		},
+	})
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Numeric,
+		ToType:   pgtypes.Int32,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			d := val.(*apd.Decimal)
+			if d.Cmp(pgtypes.NumericValueMinInt32) < 0 || d.Cmp(pgtypes.NumericValueMaxInt32) > 0 {
+				return nil, errors.Wrap(pgtypes.ErrCastOutOfRange, "integer out of range")
+			}
+			i := types.DecimalRoundedIntPart(d)
+			return int32(i), nil
+		},
+	})
+	framework.MustAddAssignmentTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Numeric,
+		ToType:   pgtypes.Int64,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			d := val.(*apd.Decimal)
+			if d.Cmp(pgtypes.NumericValueMinInt64) < 0 || d.Cmp(pgtypes.NumericValueMaxInt64) > 0 {
+				return nil, errors.Wrap(pgtypes.ErrCastOutOfRange, "bigint out of range")
+			}
+			return types.DecimalRoundedIntPart(d), nil
+		},
+	})
+}
+
+// numericImplicit registers all implicit casts. This comprises only the source types.
+func numericImplicit(builtInCasts map[id.Cast]casts.Cast) {
+	framework.MustAddImplicitTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Numeric,
+		ToType:   pgtypes.Float32,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			d := val.(*apd.Decimal)
+			f, _ := d.Float64()
+			return float32(f), nil
+		},
+	})
+	framework.MustAddImplicitTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Numeric,
+		ToType:   pgtypes.Float64,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			d := val.(*apd.Decimal)
+			f, _ := d.Float64()
+			return f, nil
+		},
+	})
+	framework.MustAddImplicitTypeCast(builtInCasts, framework.TypeCast{
+		FromType: pgtypes.Numeric,
+		ToType:   pgtypes.Numeric,
+		Function: func(ctx *sql.Context, val any, _, targetType *pgtypes.DoltgresType) (any, error) {
+			return pgtypes.GetNumericValueWithTypmod(val.(*apd.Decimal), targetType.GetAttTypMod())
+		},
+	})
+}