added libsvm wrapper

lib/pure/oids.nim

@@ -0,0 +1,81 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2012 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Nimrod OID support. An OID consists of a timestamp, a unique counter
+## and a random value. This combination should suffice to produce a globally
+## distributed unique ID. This implementation was extracted from the
+## Mongodb interface. This calls ``math.randomize()`` for the first call of
+## ``genOid``.
+
+import times, endians
+
+type
+  Toid* {.pure, final.} = object ## an OID
+    time: int32  ## 
+    fuzz: int32  ## 
+    count: int32 ## 
+
+proc hexbyte*(hex: char): int = 
+  case hex
+  of '0'..'9': result = (ord(hex) - ord('0'))
+  of 'a'..'f': result = (ord(hex) - ord('a') + 10)
+  of 'A'..'F': result = (ord(hex) - ord('A') + 10)
+  else: nil
+
+proc parseOid*(str: cstring): TOid =
+  ## parses an OID.
+  var bytes = cast[cstring](addr(result.time))
+  var i = 0
+  while i < 12:
+    bytes[i] = chr((hexbyte(str[2 * i]) shl 4) or hexbyte(str[2 * i + 1]))
+    inc(i)
+
+proc oidToString*(oid: TOid, str: cstring) = 
+  const hex = "0123456789abcdef"
+  # work around a compiler bug:
+  var str = str
+  var o = oid
+  var bytes = cast[cstring](addr(o))
+  var i = 0
+  while i < 12:
+    let b = bytes[i].ord
+    str[2 * i] = hex[(b and 0xF0) shr 4]
+    str[2 * i + 1] = hex[b and 0xF]
+    inc(i)
+  str[24] = '\0'
+
+var
+  incr, fuzz: int
+
+proc genOid*(): TOid =
+  ## generates a new OID.
+  proc rand(): cint {.importc: "rand", nodecl.}
+  proc gettime(dummy: ptr cint): cint {.importc: "time", header: "<time.h>".}
+  proc srand(seed: cint) {.importc: "srand", nodecl.}
+
+  var t = gettime(nil)
+  
+  var i = int32(incr)
+  atomicInc(incr)
+  
+  if fuzz == 0:
+    # racy, but fine semantically:
+    srand(t)
+    fuzz = rand()
+  bigEndian32(addr result.time, addr(t))
+  result.fuzz = fuzz
+  bigEndian32(addr result.count, addr(i))
+
+proc generatedTime*(oid: TOid): TTime =
+  ## returns the generated timestamp of the OID.
+  var tmp: int32
+  var dummy = oid.time
+  bigEndian32(addr(tmp), addr(dummy))
+  result = TTime(tmp)
+