namespace Org.BouncyCastle.Apache.Bzip2;

internal class CRC
{
	public static readonly int[] crc32Table = new int[256]
	{
		0, 79764919, 159529838, 222504665, 319059676, 398814059, 445009330, 507990021, 638119352, 583659535,
		797628118, 726387553, 890018660, 835552979, 1015980042, 944750013, 1276238704, 1221641927, 1167319070, 1095957929,
		1595256236, 1540665371, 1452775106, 1381403509, 1780037320, 1859660671, 1671105958, 1733955601, 2031960084, 2111593891,
		1889500026, 1952343757, -1742489888, -1662866601, -1851683442, -1788833735, -1960329156, -1880695413, -2103051438, -2040207643,
		-1104454824, -1159051537, -1213636554, -1284997759, -1389417084, -1444007885, -1532160278, -1603531939, -734892656, -789352409,
		-575645954, -646886583, -952755380, -1007220997, -827056094, -898286187, -231047128, -151282273, -71779514, -8804623,
		-515967244, -436212925, -390279782, -327299027, 881225847, 809987520, 1023691545, 969234094, 662832811, 591600412,
		771767749, 717299826, 311336399, 374308984, 453813921, 533576470, 25881363, 88864420, 134795389, 214552010,
		2023205639, 2086057648, 1897238633, 1976864222, 1804852699, 1867694188, 1645340341, 1724971778, 1587496639, 1516133128,
		1461550545, 1406951526, 1302016099, 1230646740, 1142491917, 1087903418, -1398421865, -1469785312, -1524105735, -1578704818,
		-1079922613, -1151291908, -1239184603, -1293773166, -1968362705, -1905510760, -2094067647, -2014441994, -1716953613, -1654112188,
		-1876203875, -1796572374, -525066777, -462094256, -382327159, -302564546, -206542021, -143559028, -97365931, -17609246,
		-960696225, -1031934488, -817968335, -872425850, -709327229, -780559564, -600130067, -654598054, 1762451694, 1842216281,
		1619975040, 1682949687, 2047383090, 2127137669, 1938468188, 2001449195, 1325665622, 1271206113, 1183200824, 1111960463,
		1543535498, 1489069629, 1434599652, 1363369299, 622672798, 568075817, 748617968, 677256519, 907627842, 853037301,
		1067152940, 995781531, 51762726, 131386257, 177728840, 240578815, 269590778, 349224269, 429104020, 491947555,
		-248556018, -168932423, -122852000, -60002089, -500490030, -420856475, -341238852, -278395381, -685261898, -739858943,
		-559578920, -630940305, -1004286614, -1058877219, -845023740, -916395085, -1119974018, -1174433591, -1262701040, -1333941337,
		-1371866206, -1426332139, -1481064244, -1552294533, -1690935098, -1611170447, -1833673816, -1770699233, -2009983462, -1930228819,
		-2119160460, -2056179517, 1569362073, 1498123566, 1409854455, 1355396672, 1317987909, 1246755826, 1192025387, 1137557660,
		2072149281, 2135122070, 1912620623, 1992383480, 1753615357, 1816598090, 1627664531, 1707420964, 295390185, 358241886,
		404320391, 483945776, 43990325, 106832002, 186451547, 266083308, 932423249, 861060070, 1041341759, 986742920,
		613929101, 542559546, 756411363, 701822548, -978770311, -1050133554, -869589737, -924188512, -693284699, -764654318,
		-550540341, -605129092, -475935807, -413084042, -366743377, -287118056, -257573603, -194731862, -114850189, -35218492,
		-1984365303, -1921392450, -2143631769, -2063868976, -1698919467, -1635936670, -1824608069, -1744851700, -1347415887, -1418654458,
		-1506661409, -1561119128, -1129027987, -1200260134, -1254728445, -1309196108
	};

	internal int globalCrc;

	public CRC()
	{
		InitialiseCRC();
	}

	internal void InitialiseCRC()
	{
		globalCrc = -1;
	}

	internal int GetFinalCRC()
	{
		return ~globalCrc;
	}

	internal int GetGlobalCRC()
	{
		return globalCrc;
	}

	internal void SetGlobalCRC(int newCrc)
	{
		globalCrc = newCrc;
	}

	internal void UpdateCRC(int inCh)
	{
		int num = (globalCrc >> 24) ^ inCh;
		if (num < 0)
		{
			num = 256 + num;
		}
		globalCrc = (globalCrc << 8) ^ crc32Table[num];
	}
}