1 files changed, 188 insertions, 0 deletions
diff --git a/nim/crc.pas b/nim/crc.pas
new file mode 100755
index 000000000..d669c17ee
--- /dev/null
+++ b/nim/crc.pas
@@ -0,0 +1,188 @@
+//
+//
+//           The Nimrod Compiler
+//        (c) Copyright 2008 Andreas Rumpf
+//
+//    See the file "copying.txt", included in this
+//    distribution, for details about the copyright.
+//
+unit crc;
+
+interface
+
+{$include 'config.inc'}
+
+uses
+  nsystem, strutils;
+
+type
+  TCrc32 = int32;
+
+const
+  InitCrc32 = TCrc32($ffffffff);
+
+function updateCrc32(val: Byte; crc: TCrc32): TCrc32; overload;
+function updateCrc32(val: Char; crc: TCrc32): TCrc32; overload;
+
+function crcFromBuf(buf: Pointer; len: int): TCrc32;
+function strCrc32(const s: string): TCrc32;
+
+function crcFromFile(const filename: string): TCrc32;
+
+implementation
+
+{@ignore}
+{$ifopt Q+} { we need Q- here! }
+  {$define Q_on}
+  {$Q-}
+{$endif}
+
+{$ifopt R+}
+  {$define R_on}
+  {$R-}
+{$endif}
+{@emit}
+
+{@ignore}
+type
+  TCRC_TabEntry = TCrc32;
+{@emit
+type
+  TCRC_TabEntry = int
+}
+
+const
+  crc32table: array [0..255] of TCRC_TabEntry = (
+    0, 1996959894, -301047508, -1727442502,
+    124634137, 1886057615, -379345611, -1637575261,
+    249268274, 2044508324, -522852066, -1747789432,
+    162941995, 2125561021, -407360249, -1866523247,
+    498536548, 1789927666, -205950648, -2067906082,
+    450548861, 1843258603, -187386543, -2083289657,
+    325883990, 1684777152, -43845254, -1973040660,
+    335633487, 1661365465, -99664541, -1928851979,
+    997073096, 1281953886, -715111964, -1570279054,
+    1006888145, 1258607687, -770865667, -1526024853,
+    901097722, 1119000684, -608450090, -1396901568,
+    853044451, 1172266101, -589951537, -1412350631,
+    651767980, 1373503546, -925412992, -1076862698,
+    565507253, 1454621731, -809855591, -1195530993,
+    671266974, 1594198024, -972236366, -1324619484,
+    795835527, 1483230225, -1050600021, -1234817731,
+    1994146192, 31158534, -1731059524, -271249366,
+    1907459465, 112637215, -1614814043, -390540237,
+    2013776290, 251722036, -1777751922, -519137256,
+    2137656763, 141376813, -1855689577, -429695999,
+    1802195444, 476864866, -2056965928, -228458418,
+    1812370925, 453092731, -2113342271, -183516073,
+    1706088902, 314042704, -1950435094, -54949764,
+    1658658271, 366619977, -1932296973, -69972891,
+    1303535960, 984961486, -1547960204, -725929758,
+    1256170817, 1037604311, -1529756563, -740887301,
+    1131014506, 879679996, -1385723834, -631195440,
+    1141124467, 855842277, -1442165665, -586318647,
+    1342533948, 654459306, -1106571248, -921952122,
+    1466479909, 544179635, -1184443383, -832445281,
+    1591671054, 702138776, -1328506846, -942167884,
+    1504918807, 783551873, -1212326853, -1061524307,
+    -306674912, -1698712650, 62317068, 1957810842,
+    -355121351, -1647151185, 81470997, 1943803523,
+    -480048366, -1805370492, 225274430, 2053790376,
+    -468791541, -1828061283, 167816743, 2097651377,
+    -267414716, -2029476910, 503444072, 1762050814,
+    -144550051, -2140837941, 426522225, 1852507879,
+    -19653770, -1982649376, 282753626, 1742555852,
+    -105259153, -1900089351, 397917763, 1622183637,
+    -690576408, -1580100738, 953729732, 1340076626,
+    -776247311, -1497606297, 1068828381, 1219638859,
+    -670225446, -1358292148, 906185462, 1090812512,
+    -547295293, -1469587627, 829329135, 1181335161,
+    -882789492, -1134132454, 628085408, 1382605366,
+    -871598187, -1156888829, 570562233, 1426400815,
+    -977650754, -1296233688, 733239954, 1555261956,
+    -1026031705, -1244606671, 752459403, 1541320221,
+    -1687895376, -328994266, 1969922972, 40735498,
+    -1677130071, -351390145, 1913087877, 83908371,
+    -1782625662, -491226604, 2075208622, 213261112,
+    -1831694693, -438977011, 2094854071, 198958881,
+    -2032938284, -237706686, 1759359992, 534414190,
+    -2118248755, -155638181, 1873836001, 414664567,
+    -2012718362, -15766928, 1711684554, 285281116,
+    -1889165569, -127750551, 1634467795, 376229701,
+    -1609899400, -686959890, 1308918612, 956543938,
+    -1486412191, -799009033, 1231636301, 1047427035,
+    -1362007478, -640263460, 1088359270, 936918000,
+    -1447252397, -558129467, 1202900863, 817233897,
+    -1111625188, -893730166, 1404277552, 615818150,
+    -1160759803, -841546093, 1423857449, 601450431,
+    -1285129682, -1000256840, 1567103746, 711928724,
+    -1274298825, -1022587231, 1510334235, 755167117
+  );
+
+function updateCrc32(val: Byte; crc: TCrc32): TCrc32; overload;
+begin
+  result := crc32Table[(int(crc) xor val) and $ff] xor (crc shr 8);
+end;
+
+function updateCrc32(val: Char; crc: TCrc32): TCrc32; overload;
+begin
+  result := updateCrc32(ord(val), crc);
+end;
+
+function strCrc32(const s: string): TCrc32;
+var
+  i: int;
+begin
+  result := InitCrc32;
+  for i := strStart to length(s)+StrStart-1 do
+    result := updateCrc32(s[i], result)
+end;
+
+type
+  TByteArray = array [0..10000000] of Byte;
+  PByteArray = ^TByteArray;
+function crcFromBuf(buf: Pointer; len: int): TCrc32;
+var
+  p: PByteArray;
+  i: int;
+begin
+  p := {@cast}PByteArray(buf);
+  result := InitCrc32;
+  for i := 0 to len-1 do result := updateCrc32(p[i], result)
+end;
+
+function crcFromFile(const filename: string): TCrc32;
+const
+  bufSize = 8 * 1024;
+var
+  bin: TBinaryFile;
+  buf: Pointer;
+  readBytes, i: int;
+  p: PByteArray;
+begin
+  result := InitCrc32;
+  if not openFile(bin, filename) then exit; // not equal if file does not exist
+  buf := alloc(BufSize);
+  p := {@cast}PByteArray(buf);
+  while true do begin
+    readBytes := readBuffer(bin, buf, bufSize);
+    for i := 0 to readBytes-1 do result := updateCrc32(p[i], result);
+    if readBytes <> bufSize then break;
+  end;
+  dealloc(buf);
+  CloseFile(bin);
+end;
+
+{@ignore}
+{$ifdef Q_on}
+  {$undef Q_on}
+  {$Q+}
+{$endif}
+
+{$ifdef R_on}
+  {$undef R_on}
+  {$R+}
+{$endif}
+{@emit}
+
+end.