presto-parquet/src/main/java/io/prestosql/parquet/reader/ShortDecimalColumnReader.java/ShortDecimalColumnReader/readValue
class ShortDecimalColumnReader:    @Override
    protected void readValue(BlockBuilder blockBuilder, Type type)
    {
        if (definitionLevel == columnDescriptor.getMaxDefinitionLevel()) {
            long decimalValue;
            // When decimals are encoded with primitive types Parquet stores unscaled values
            if (columnDescriptor.getPrimitiveType().getPrimitiveTypeName() == INT32) {
                decimalValue = valuesReader.readInteger();
            }
            else if (columnDescriptor.getPrimitiveType().getPrimitiveTypeName() == INT64) {
                decimalValue = valuesReader.readLong();
            }
            else {
                decimalValue = getShortDecimalValue(valuesReader.readBytes().getBytes());
            }

            if (isShortDecimal(type)) {
                type.writeLong(blockBuilder, decimalValue);
            }
            else {
                type.writeSlice(blockBuilder, unscaledDecimal(decimalValue));
            }
        }
        else if (isValueNull()) {
            blockBuilder.appendNull();
        }
    }