package com.gamebuster19901.excite.crc;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;

import org.apache.commons.io.IOUtils;

public class CRCTester {
	private final byte[] data;
	
	public CRCTester(InputStream inputStream) throws IOException {
		this(IOUtils.toByteArray(inputStream));
	}
	
	public CRCTester(byte[] data) {
		this.data = data;
	}
	
	public int test(final int seed) {
		
		ByteBuffer param1 = ByteBuffer.wrap(data);
		int length = data.length;
		
		byte pos1;
		byte pos2;
		byte pos3;
		byte pos4;
		byte pos5;
		byte pos6;
		
		byte bVar7;
		boolean bVar8;
		int leftoverBytes;
		int bytesEvaluated;
		@Unsigned int uVar11;
		@Unsigned int cyclesRemaining;
		
		uVar11 = seed;
		
		int dataPointer = 0;
		
		if(3 < length) {
			pos1 = param1.get(0);
			length = length - 4;
			pos2 = param1.get(1);
			bVar7 = pos1;
			pos3 = param1.get(2);
			
			param1.getInt();
			dataPointer = dataPointer + 4;
			
			uVar11 = ~(bVar7 << 0x18 | pos1 << 0x10 | pos2 << 8 | pos3);
		}
	
		bytesEvaluated = 0;
		if(0 < length) {
			if (8 < length) {
				bVar8 = false;
				if (-1 < length && length < 0x7fffffff) {
					bVar8 = true;
				}
				cyclesRemaining = length - 1 >>> 3;
				if(bVar8 
						&& 0 < length - 8) { //this is almost certainty a for loop. Also cyclesRemaining = (maxLength - 1) / 8
					do {
						bytesEvaluated = bytesEvaluated + 8;
						uVar11 = (uVar11 << 8 | param1.getInt(0)) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						pos1 = param1.get(dataPointer + 1);
						pos2 = param1.get(dataPointer + 2);
						pos3 = param1.get(dataPointer + 3);
						uVar11 = (uVar11 << 8 | param1.getInt(1)) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						pos4 = param1.get(dataPointer + 4);
						pos5 = param1.get(dataPointer + 5);
						pos6 = param1.get(dataPointer + 6);
						
						param1.getLong();
						dataPointer = dataPointer + 8;
						
						uVar11 = (uVar11 << 8 | pos1) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						uVar11 = (uVar11 << 8 | pos2) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						uVar11 = (uVar11 << 8 | pos3) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						uVar11 = (uVar11 << 8 | pos4) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						uVar11 = (uVar11 << 8 | pos5) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						uVar11 = (uVar11 << 8 | pos6) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
						cyclesRemaining = cyclesRemaining - 1;
					}
					while (cyclesRemaining != 0);
				}
			}
			leftoverBytes = length - bytesEvaluated;
			if(bytesEvaluated < length) {
				do {
					bVar7 = param1.get(dataPointer);
					dataPointer = dataPointer++;
					
					uVar11 = (uVar11 << 8 | bVar7) ^ (seed + (uVar11 >>> 0x16 & 0x3fc));
					leftoverBytes = leftoverBytes - 1;
				}
				while (leftoverBytes != 0);
			}
		}
		return ~uVar11;
	}
	
	
}