content: /* ###
   * IP: GHIDRA
   *
   * 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 firmware.option_rom;
  
  import ghidra.app.util.bin.BinaryReader;
  
  import java.io.IOException;
  
  /**
   * Factory for constructing the correct option ROM type based off the code type field in the PCI
   * data structure header.
   */
  public class OptionROMHeaderFactory {
  	private OptionROMHeaderFactory() {}
  
  	/**
  	 * Constructs an OptionROMHeader from a specified BinaryReader by checking the code type field
  	 * in the PCI data structure header.
  	 *
  	 * @param reader the specified BinaryReader
  	 * @return       the parsed OptionROMHeader
  	 */
  	public static OptionROMHeader parseOptionROM(BinaryReader reader) throws IOException {
  		short signature = reader.peekNextShort();
  		if (signature != OptionROMConstants.ROM_SIGNATURE) {
  			throw new IOException("Not a valid PCI option ROM header");
  		}
  
  		// Read the PCI data structure offset field in the ROM header.
  		short pcirOffset = reader.readShort(0x18);
  
  		// Construct the correct OptionROMHeader based off the code type.
  		byte codeType = reader.readByte(pcirOffset + 0x14);
  		switch (codeType) {
  			case OptionROMConstants.CodeType.PC_AT_COMPATIBLE:
  				return new LegacyOptionROMHeader(reader);
  			case OptionROMConstants.CodeType.EFI:
  				return new UEFIOptionROMHeader(reader);
  			default:
  				return new OptionROMHeader(reader);
  		}
  	}
  }
  