bitwise.go

// Copyright 2023 The Expr Authors
// 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 expr

import (
	"fmt"
	"go/ast"
	"go/token"

	"github.com/muktihari/expr/internal/conv"
)

func bitwise(v, vx, vy *Visitor, binaryExpr *ast.BinaryExpr) {
	// numeric guards:
	if vx.value.Kind() <= numeric_beg || vx.value.Kind() >= numeric_end {
		v.err = newBitwiseNonIntegerError(vx, binaryExpr.X)
		return
	}
	if vy.value.Kind() <= numeric_beg || vy.value.Kind() >= numeric_end {
		v.err = newBitwiseNonIntegerError(vy, binaryExpr.Y)
		return
	}

	var x, y int64
	switch v.options.numericType {
	case NumericTypeFloat:
		v.err = newBitwiseNonIntegerError(v, binaryExpr)
		return
	case NumericTypeComplex:
		v.err = newBitwiseNonIntegerError(v, binaryExpr)
		return
	case NumericTypeInt:
		x = parseInt(vx.value)
		y = parseInt(vy.value)
	case NumericTypeAuto:
		var ok bool
		x, ok = convertToInt64(vx.value)
		if !ok {
			v.err = newBitwiseNonIntegerError(vx, binaryExpr.X)
			return
		}
		y, ok = convertToInt64(vy.value)
		if !ok {
			v.err = newBitwiseNonIntegerError(vy, binaryExpr.Y)
			return
		}
	}

	v.value.SetKind(KindInt)
	switch binaryExpr.Op {
	case token.AND:
		v.value = int64Value(x & y)
	case token.OR:
		v.value = int64Value(x | y)
	case token.XOR:
		v.value = int64Value(x ^ y)
	case token.AND_NOT:
		v.value = int64Value(x &^ y)
	case token.SHL:
		v.value = int64Value(x << y)
	case token.SHR:
		v.value = int64Value(x >> y)
	}
}

func newBitwiseNonIntegerError(v *Visitor, e ast.Expr) error {
	s := conv.FormatExpr(e)
	return &SyntaxError{
		Msg: "result value of \"" + s + "\" is \"" + fmt.Sprintf("%v", v.value.Any()) + "\" which is not an integer",
		Pos: int(e.Pos()),
		Err: ErrBitwiseOperation,
	}
}

func convertToInt64(val value) (int64, bool) {
	switch val.Kind() {
	case KindFloat:
		f := val.Float64()
		if float64(int64(f)) == f { // only if it doesn't have decimal.
			return int64(f), true
		}
	case KindInt:
		return val.Int64(), true
	}
	return 0, false
}