1 files changed, 145 insertions, 0 deletions
diff --git a/rod/crc.nim b/rod/crc.nim
new file mode 100755
index 000000000..e66ce30fb
--- /dev/null
+++ b/rod/crc.nim
@@ -0,0 +1,145 @@
+#
+#
+#           The Nimrod Compiler
+#        (c) Copyright 2008 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+import 
+  strutils
+
+type 
+  TCrc32* = int32
+
+const 
+  InitCrc32* = TCrc32(- 1)
+  InitAdler32* = int32(1)
+
+proc updateCrc32*(val: int8, crc: TCrc32): TCrc32
+proc updateCrc32*(val: Char, crc: TCrc32): TCrc32
+proc crcFromBuf*(buf: Pointer, length: int): TCrc32
+proc strCrc32*(s: string): TCrc32
+proc crcFromFile*(filename: string): TCrc32
+proc updateAdler32*(adler: int32, buf: pointer, length: int): int32
+# implementation
+
+type 
+  TCRC_TabEntry = int
+
+const 
+  crc32table: array[0..255, 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]
+
+proc updateCrc32(val: int8, crc: TCrc32): TCrc32 = 
+  result = TCrc32(crc32Table[(int(crc) xor (int(val) and 0x000000FF)) and
+      0x000000FF]) xor (crc shr TCrc32(8))
+
+proc updateCrc32(val: Char, crc: TCrc32): TCrc32 = 
+  result = updateCrc32(int8(ord(val)), crc)
+
+proc strCrc32(s: string): TCrc32 = 
+  result = InitCrc32
+  for i in countup(0, len(s) + 0 - 1): result = updateCrc32(s[i], result)
+  
+type 
+  TByteArray = array[0..10000000, int8]
+  PByteArray = ref TByteArray
+
+proc crcFromBuf(buf: Pointer, length: int): TCrc32 = 
+  var p: PByteArray
+  p = cast[PByteArray](buf)
+  result = InitCrc32
+  for i in countup(0, length - 1): result = updateCrc32(p[i], result)
+  
+proc crcFromFile(filename: string): TCrc32 = 
+  const 
+    bufSize = 8 * 1024
+  var 
+    bin: tfile
+    buf: Pointer
+    readBytes: int
+    p: PByteArray
+  result = InitCrc32
+  if not open(bin, filename): 
+    return                    # not equal if file does not exist
+  buf = alloc(BufSize)
+  p = cast[PByteArray](buf)
+  while true: 
+    readBytes = readBuffer(bin, buf, bufSize)
+    for i in countup(0, readBytes - 1): result = updateCrc32(p[i], result)
+    if readBytes != bufSize: break 
+  dealloc(buf)
+  close(bin)
+
+const 
+  base = int32(65521) # largest prime smaller than 65536 
+                      #NMAX = 5552; original code with unsigned 32 bit integer 
+                      # NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 
+  nmax = 3854 # code with signed 32 bit integer 
+              # NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^31-1 
+              # The penalty is the time loss in the extra MOD-calls. 
+
+proc updateAdler32(adler: int32, buf: pointer, length: int): int32 = 
+  var 
+    s1, s2: int32
+    L, k, b: int
+  s1 = adler and int32(0x0000FFFF)
+  s2 = (adler shr int32(16)) and int32(0x0000FFFF)
+  L = length
+  b = 0
+  while (L > 0): 
+    if L < nmax: k = L
+    else: k = nmax
+    dec(L, k)
+    while (k > 0): 
+      s1 = s1 +% int32((cast[cstring](buf))[b])
+      s2 = s2 +% s1
+      inc(b)
+      dec(k)
+    s1 = `%%`(s1, base)
+    s2 = `%%`(s2, base)
+  result = (s2 shl int32(16)) or s1