code: /* ###
   * 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 ghidra.app.util.bin.format.pe.cli.blobs;
  
  import java.io.IOException;
  
  import ghidra.app.util.bin.BinaryReader;
  import ghidra.app.util.bin.format.pe.cli.streams.CliStreamMetadata;
  import ghidra.program.model.data.*;
  import ghidra.util.exception.InvalidInputException;
  
  public class CliSigStandAloneMethod extends CliAbstractSig {
  
  	private CliRetType retType;
  	private CliParam params[];
  	private byte flags;
  	private int sizeOfCount;
  	private int sentinelIndex; // SENTINEL is before the parameter index in this field
  
  	// Note: The only difference between this and the MethodRefSig is the number of
  	// values that can be included in the first byte
  
  	private final int STANDALONEMETHODSIG_FLAGS_DEFAULT = 0x0;
  	private final int STANDALONEMETHODSIG_FLAGS_HASTHIS = 0x20;
  	private final int STANDALONEMETHODSIG_FLAGS_EXPLICITTHIS = 0x40;
  	private final int STANDALONEMETHODSIG_FLAGS_VARARG = 0x5;
  	private final int STANDALONEMETHODSIG_FLAGS_C = 0x01;
  	private final int STANDALONEMETHODSIG_FLAGS_STDCALL = 0x02;
  	private final int STANDALONEMETHODSIG_FLAGS_THISCALL = 0x03;
  	private final int STANDALONEMETHODSIG_FLAGS_FASTCALL = 0x04;
  
  	public enum CallingConvention {
  		MANAGED, C, STDCALL, THISCALL, FASTCALL
  	}
  
  	public CliSigStandAloneMethod(CliBlob blob) throws IOException {
  		super(blob);
  		sentinelIndex = -1;
  
  		// Read the flags
  		BinaryReader reader = getContentsReader();
  		flags = reader.readNextByte();
  
  		long origIndex = reader.getPointerIndex();
  		int paramCount = decodeCompressedUnsignedInt(reader);
  		this.sizeOfCount = (int) (reader.getPointerIndex() - origIndex);
  
  		try {
  			retType = new CliRetType(reader);
  		}
  		catch (InvalidInputException e) {
  			retType = null;
  		}
  
  		params = new CliParam[paramCount];
  		for (int i = 0; i < paramCount; i++) {
  			if (reader.peekNextByte() == CliElementType.ELEMENT_TYPE_SENTINEL.id()) {
  				reader.readNextByte();
  				sentinelIndex = i;
  			}
  			try {
  				params[i] = new CliParam(reader);
  			}
  			catch (InvalidInputException e) {
  				params[i] = null;
  			}
  		}
  	}
  
  	@Override
  	public String getContentsName() {
  		return "StandAloneMethodSig";
  	}
  
  	@Override
  	public String getContentsComment() {
  		return "Typically for calli instruction; Type info for method return and params";
  	}
  
  	@Override
  	public DataType getContentsDataType() {
  		StructureDataType struct = new StructureDataType(new CategoryPath(PATH), getName(), 0);
  		struct.add(BYTE, "flags",
  			"ORed VARARG/DEFAULT/C/STDCALL/THISCALL/FASTCALL and HASTHIS/EXPLICITTHIS");
  		struct.add(getDataTypeForBytes(sizeOfCount), "Count",
  			"Number of param types to follow RetType");
  		struct.add(retType.getDefinitionDataType(), "RetType", null);
  		for (CliParam param : params) {
  			struct.add(param.getDefinitionDataType(), null, null);
  		}
  		return struct;
  	}
  
  	public CliRetType getReturnType() {
  		return retType;
  	}
  
  	public CliParam[] getParams() {
  		return params.clone();
  	}
  
  	public boolean hasThis() {
  		return (flags & STANDALONEMETHODSIG_FLAGS_HASTHIS) == STANDALONEMETHODSIG_FLAGS_HASTHIS;
  	}
  
  	public boolean hasExplicitThis() {
  		return (flags &
  			STANDALONEMETHODSIG_FLAGS_EXPLICITTHIS) == STANDALONEMETHODSIG_FLAGS_EXPLICITTHIS;
  	}
  
  	public boolean hasVarArgs() {
  		return (flags & STANDALONEMETHODSIG_FLAGS_VARARG) == STANDALONEMETHODSIG_FLAGS_VARARG;
  	}
  
  	public CallingConvention getCallingConvention() {
  		if ((flags & STANDALONEMETHODSIG_FLAGS_C) == STANDALONEMETHODSIG_FLAGS_C) {
  			// cdecl
  			return CallingConvention.C;
  		}
  		else if ((flags & STANDALONEMETHODSIG_FLAGS_STDCALL) == STANDALONEMETHODSIG_FLAGS_STDCALL) {
  			// stdcall
  			return CallingConvention.STDCALL;
  		}
  		else if ((flags &
  			STANDALONEMETHODSIG_FLAGS_THISCALL) == STANDALONEMETHODSIG_FLAGS_THISCALL) {
  			// ecx/rcx is this pointer
  			return CallingConvention.THISCALL;
  		}
  		else if ((flags &
  			STANDALONEMETHODSIG_FLAGS_FASTCALL) == STANDALONEMETHODSIG_FLAGS_FASTCALL) {
  			// ecx/rcx and edx/rdx are the first two parameters, standard x64 convention
  			return CallingConvention.FASTCALL;
  		}
  
  		// Managed code call
  		return CallingConvention.MANAGED;
  	}
  
  	@Override
  	public String getRepresentationCommon(CliStreamMetadata stream, boolean isShort) {
  		String rep = getRepresentationOf(retType, stream, isShort) + " fn(";
  
  		for (CliParam param : params) {
  			if (param == null) {
  				rep += "unidentified_param_type, ";
  			}
  			else {
  				rep += getRepresentationOf(param, stream, isShort) + ", ";
  			}
  		}
  		if (params.length > 0) {
  			rep = rep.substring(0, rep.length() - 2); // Take off last comma+space
  		}
  		rep += ")";
  		return rep;
  	}
  
  }
  