Add reversed bytes function.

.gitignore

@@ -4,3 +4,4 @@
 
 /EarthboundBattleBackgrounds/.vs/EarthboundBattleBackgrounds
 /EarthboundBattleBackgrounds/EarthboundBattleBackgrounds/x64/Debug
+/.vs/EarthboundBattleBackgrounds/v17

EarthboundBattleBackgrounds/EarthboundBattleBackgrounds/main.cpp

@@ -122,9 +122,57 @@ struct Rom{
 			uint32_t pos{ptrStart};
 			uint32_t bpos{};
 			uint32_t bpos2{};
+			char tmp;
 			int read{};
 			while(data[pos]!=0xFF){
+				if (pos >= data.length())return;
+				char commandType{data[pos]>>5};
+				char len{data[pos]&0x1F+1};
+				if(commandType==7){
+					commandType=(data[pos]&0x1C)>>2;
+					len=((data[pos]&3)<<8)+data[pos+1]+1;
+					++pos;
+				}
+				if(bpos+len>maxLength||bpos+len<0)return;
+				if(commandType>=4) {
+					bpos2=(data[pos]<<8)+data[pos+1];
+					if(bpos2>=maxLength||bpos2<0)return;
+					pos+=2;
+				}
+				switch(commandType) {
+					case UNCOMPRESSED_BLOCK:{
+						while(len--!=0)block[bpos++]=data[pos++];
+					}break;
+					case RUN_LENGTH_ENCODED_BYTE:{
+						while(len--!=0)block[bpos++]=data[pos];
+						++pos;
+					}break;
+					case RUN_LENGTH_ENCODED_SHORT:{
+						if(bpos+2*len>maxLength||bpos<0)return;
+						while(len--!=0){
+							block[bpos++]=data[pos];
+							block[bpos++]=data[pos+1];
+						}
+					}break;
+					case INCREMENTAL_SEQUENCE:{
+						tmp=data[pos++];
+						while(len--!=0)block[bpos++]=tmp++;
+					}break;
+					case REPEAT_PREVIOUS_DATA:{
+						if(bpos+2*len>maxLength||bpos<0)return;
+						for(int i:std::views::iota(0,len))block[bpos++]=block[bpos2+i];
+					}break;
+					case REVERSE_BITS:{
+						if(bpos+2*len>maxLength||bpos<0)return;
+						while(len--!=0)block[bpos++]=Rom::reversedBytes[block[bpos2++]&0xFF];
+					}break;
+					case UNKNOWN_1:{
 
+					}break;
+					case UNKNOWN_2:{
+
+					}break;
+				}
 			}
 		}
 	};
@@ -189,10 +237,24 @@ struct Rom{
 		}
 	};
 	std::string data;
+	inline static std::string reversedBytes;
 	std::vector<BattleBackground>backgrounds;
 	std::vector<BackgroundPalette>palettes;
 	std::vector<BackgroundGraphics>graphics;
 	Rom(){
+		#pragma region Setup Reversed Bytes
+			reversedBytes.resize(256);
+			for(int i:std::views::iota(0U,reversedBytes.size())){
+				uint8_t newNumb{};
+				for(int digit=0;digit<8;digit++){
+					uint8_t digitVal{1U<<digit};
+					if(i&digitVal)newNumb|=1<<(7-digit);
+				}
+				reversedBytes[i]=newNumb;
+				i++;
+			}
+		#pragma endregion
+
 		std::ifstream dataStream{"truncated_backgrounds.dat",std::ios_base::binary};
 		while(dataStream.good())data+=dataStream.get();