decode the Avro logical type Decimal

decode_decimal.go

func decodeAvroDecimal(data []byte) float64 {
	number := new(big.Int).SetBytes(data)

	// Check if the number is negative
	mostSignificantBit := byte(0x80)
	if data[0]&mostSignificantBit > 0 {
		// For negative numbers, take two's complement
		number.Sub(number, new(big.Int).Lsh(big.NewInt(1), uint(len(data))*8))
	}

	decimalRep := decimal.NewFromInt(number.Int64())
	divisor := decimal.NewFromInt(baseOfDecimal).Pow(decimal.NewFromInt(scale))
	decimalRep = decimalRep.Div(divisor)

	fVal, _ := decimalRep.Float64()
	return fVal
}