ns-usbloader/src/main/java/nsusbloader/Utilities/patches/es/finders/HeuristicEs1.java

104 lines
3.7 KiB
Java

/*
Copyright 2018-2022 Dmitry Isaenko
This file is part of NS-USBloader.
NS-USBloader is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
NS-USBloader is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with NS-USBloader. If not, see <https://www.gnu.org/licenses/>.
*/
package nsusbloader.Utilities.patches.es.finders;
import libKonogonka.Converter;
import nsusbloader.AppPreferences;
import nsusbloader.Utilities.patches.AHeuristic;
import nsusbloader.Utilities.patches.BinToAsmPrinter;
import nsusbloader.Utilities.patches.SimplyFind;
import java.util.List;
class HeuristicEs1 extends AHeuristic {
private static final String PATTERN = AppPreferences.getInstance().getPatchPattern("ES", 1, 0);
private final List<Integer> findings;
private final byte[] where;
HeuristicEs1(byte[] where){
this.where = where;
SimplyFind simplyfind = new SimplyFind(PATTERN, where);
this.findings = simplyfind.getResults();
this.findings.removeIf(this::dropStep1);
if(findings.size() < 2)
return;
this.findings.removeIf(this::dropStep2);
}
// Check ranges
private boolean dropStep1(int offsetOfPatternFound){
return ((offsetOfPatternFound < 0x10000 || offsetOfPatternFound > 0xffffc));
}
// Remove non-CBZ
private boolean dropStep2(int offsetOfPatternFound){
return ((where[offsetOfPatternFound - 1] & (byte) 0b01111111) != 0x34);
}
@Override
public boolean isFound(){
return findings.size() == 1;
}
@Override
public boolean wantLessEntropy(){
return findings.size() > 1;
}
@Override
public int getOffset() throws Exception{
if(findings.isEmpty())
throw new Exception("Nothing found");
if (findings.size() > 1)
throw new Exception("Too many offsets");
return findings.get(0);
}
@Override
public boolean setOffsetsNearby(int offsetNearby) {
findings.removeIf(offset -> {
if (offset > offsetNearby)
return ! (offset < offsetNearby - 0xffff);
return ! (offset > offsetNearby - 0xffff);
});
return isFound();
}
@Override
public String getDetails(){
int cbzOffsetInternal = findings.get(0) - 4;
int instructionExpression = Converter.getLEint(where, cbzOffsetInternal);
int conditionalJumpLocation = ((instructionExpression >> 5 & 0x7FFFF) * 4 + cbzOffsetInternal) & 0xfffff;
int secondExpressionsPairElement1 = Converter.getLEint(where, conditionalJumpLocation);
int secondExpressionsPairElement2 = Converter.getLEint(where, conditionalJumpLocation+4);
return BinToAsmPrinter.printSimplified(instructionExpression, cbzOffsetInternal) +
BinToAsmPrinter.printSimplified(Converter.getLEint(where, cbzOffsetInternal + 4),
cbzOffsetInternal + 4) +
BinToAsmPrinter.printSimplified(Converter.getLEint(where, cbzOffsetInternal + 8),
cbzOffsetInternal + 8) +
"...\n" +
BinToAsmPrinter.printSimplified(secondExpressionsPairElement1, conditionalJumpLocation) +
BinToAsmPrinter.printSimplified(secondExpressionsPairElement2, conditionalJumpLocation + 4);
}
}