using System;
using System.Security.Cryptography;

namespace wf
{
	public class CRC32 : HashAlgorithm
	{
		public override void Initialize()
		{
			this.result = CRC32.MaskValue;
		}

		public override int HashSize
		{
			get
			{
				return 32;
			}
		}

		public uint ComputeChecksum(byte[] bytes)
		{
			uint num = CRC32.MaskValue;
			for (int i = 0; i < bytes.Length; i++)
			{
				byte b = (byte)((num & 255U) ^ (uint)bytes[i]);
				num = (num >> 8 ^ CRC32.Crc32tabel[(int)b]);
			}
			return ~num;
		}

		protected override void HashCore(byte[] array, int ibStart, int cbSize)
		{
			while (--cbSize >= 0)
			{
				this.result = (CRC32.Crc32tabel[(int)((UIntPtr)((this.result ^ (uint)array[ibStart++]) & 255U))] ^ this.result >> 8);
			}
		}

		protected override byte[] HashFinal()
		{
			this.result ^= CRC32.MaskValue;
			this.HashValue = new byte[]
			{
				(byte)(this.result >> 24 & 255U),
				(byte)(this.result >> 16 & 255U),
				(byte)(this.result >> 8 & 255U),
				(byte)(this.result & 255U)
			};
			return this.HashValue;
		}

		private static readonly uint[] Crc32tabel = new uint[]
		{
			0U,
			1996959894U,
			3993919788U,
			2567524794U,
			124634137U,
			1886057615U,
			3915621685U,
			2657392035U,
			249268274U,
			2044508324U,
			3772115230U,
			2547177864U,
			162941995U,
			2125561021U,
			3887607047U,
			2428444049U,
			498536548U,
			1789927666U,
			4089016648U,
			2227061214U,
			450548861U,
			1843258603U,
			4107580753U,
			2211677639U,
			325883990U,
			1684777152U,
			4251122042U,
			2321926636U,
			335633487U,
			1661365465U,
			4195302755U,
			2366115317U,
			997073096U,
			1281953886U,
			3579855332U,
			2724688242U,
			1006888145U,
			1258607687U,
			3524101629U,
			2768942443U,
			901097722U,
			1119000684U,
			3686517206U,
			2898065728U,
			853044451U,
			1172266101U,
			3705015759U,
			2882616665U,
			651767980U,
			1373503546U,
			3369554304U,
			3218104598U,
			565507253U,
			1454621731U,
			3485111705U,
			3099436303U,
			671266974U,
			1594198024U,
			3322730930U,
			2970347812U,
			795835527U,
			1483230225U,
			3244367275U,
			3060149565U,
			1994146192U,
			31158534U,
			2563907772U,
			4023717930U,
			1907459465U,
			112637215U,
			2680153253U,
			3904427059U,
			2013776290U,
			251722036U,
			2517215374U,
			3775830040U,
			2137656763U,
			141376813U,
			2439277719U,
			3865271297U,
			1802195444U,
			476864866U,
			2238001368U,
			4066508878U,
			1812370925U,
			453092731U,
			2181625025U,
			4111451223U,
			1706088902U,
			314042704U,
			2344532202U,
			4240017532U,
			1658658271U,
			366619977U,
			2362670323U,
			4224994405U,
			1303535960U,
			984961486U,
			2747007092U,
			3569037538U,
			1256170817U,
			1037604311U,
			2765210733U,
			3554079995U,
			1131014506U,
			879679996U,
			2909243462U,
			3663771856U,
			1141124467U,
			855842277U,
			2852801631U,
			3708648649U,
			1342533948U,
			654459306U,
			3188396048U,
			3373015174U,
			1466479909U,
			544179635U,
			3110523913U,
			3462522015U,
			1591671054U,
			702138776U,
			2966460450U,
			3352799412U,
			1504918807U,
			783551873U,
			3082640443U,
			3233442989U,
			3988292384U,
			2596254646U,
			62317068U,
			1957810842U,
			3939845945U,
			2647816111U,
			81470997U,
			1943803523U,
			3814918930U,
			2489596804U,
			225274430U,
			2053790376U,
			3826175755U,
			2466906013U,
			167816743U,
			2097651377U,
			4027552580U,
			2265490386U,
			503444072U,
			1762050814U,
			4150417245U,
			2154129355U,
			426522225U,
			1852507879U,
			4275313526U,
			2312317920U,
			282753626U,
			1742555852U,
			4189708143U,
			2394877945U,
			397917763U,
			1622183637U,
			3604390888U,
			2714866558U,
			953729732U,
			1340076626U,
			3518719985U,
			2797360999U,
			1068828381U,
			1219638859U,
			3624741850U,
			2936675148U,
			906185462U,
			1090812512U,
			3747672003U,
			2825379669U,
			829329135U,
			1181335161U,
			3412177804U,
			3160834842U,
			628085408U,
			1382605366U,
			3423369109U,
			3138078467U,
			570562233U,
			1426400815U,
			3317316542U,
			2998733608U,
			733239954U,
			1555261956U,
			3268935591U,
			3050360625U,
			752459403U,
			1541320221U,
			2607071920U,
			3965973030U,
			1969922972U,
			40735498U,
			2617837225U,
			3943577151U,
			1913087877U,
			83908371U,
			2512341634U,
			3803740692U,
			2075208622U,
			213261112U,
			2463272603U,
			3855990285U,
			2094854071U,
			198958881U,
			2262029012U,
			4057260610U,
			1759359992U,
			534414190U,
			2176718541U,
			4139329115U,
			1873836001U,
			414664567U,
			2282248934U,
			4279200368U,
			1711684554U,
			285281116U,
			2405801727U,
			4167216745U,
			1634467795U,
			376229701U,
			2685067896U,
			3608007406U,
			1308918612U,
			956543938U,
			2808555105U,
			3495958263U,
			1231636301U,
			1047427035U,
			2932959818U,
			3654703836U,
			1088359270U,
			936918000U,
			2847714899U,
			3736837829U,
			1202900863U,
			817233897U,
			3183342108U,
			3401237130U,
			1404277552U,
			615818150U,
			3134207493U,
			3453421203U,
			1423857449U,
			601450431U,
			3009837614U,
			3294710456U,
			1567103746U,
			711928724U,
			3020668471U,
			3272380065U,
			1510334235U,
			755167117U
		};

		private static readonly uint MaskValue = uint.MaxValue;

		private uint result;
	}
}