initial non-compiling version of 'parallel'

lib/pure/concurrency/cpuinfo.nim

@@ -0,0 +1,58 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2014 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements procs to determine the number of CPUs / cores.
+
+include "system/inclrtl"
+
+import strutils, os
+
+when not defined(windows):
+  import posix
+
+when defined(linux):
+  import linux
+
+when defined(macosx) or defined(bsd):
+  const
+    CTL_HW = 6
+    HW_AVAILCPU = 25
+    HW_NCPU = 3
+  proc sysctl(x: ptr array[0..3, cint], y: cint, z: pointer,
+              a: var csize, b: pointer, c: int): cint {.
+             importc: "sysctl", header: "<sys/sysctl.h>".}
+
+proc countProcessors*(): int {.rtl, extern: "ncpi$1".} =
+  ## returns the numer of the processors/cores the machine has.
+  ## Returns 0 if it cannot be detected.
+  when defined(windows):
+    var x = getEnv("NUMBER_OF_PROCESSORS")
+    if x.len > 0: result = parseInt(x.string)
+  elif defined(macosx) or defined(bsd):
+    var
+      mib: array[0..3, cint]
+      numCPU: int
+      len: csize
+    mib[0] = CTL_HW
+    mib[1] = HW_AVAILCPU
+    len = sizeof(numCPU)
+    discard sysctl(addr(mib), 2, addr(numCPU), len, nil, 0)
+    if numCPU < 1:
+      mib[1] = HW_NCPU
+      discard sysctl(addr(mib), 2, addr(numCPU), len, nil, 0)
+    result = numCPU
+  elif defined(hpux):
+    result = mpctl(MPC_GETNUMSPUS, nil, nil)
+  elif defined(irix):
+    var SC_NPROC_ONLN {.importc: "_SC_NPROC_ONLN", header: "<unistd.h>".}: cint
+    result = sysconf(SC_NPROC_ONLN)
+  else:
+    result = sysconf(SC_NPROCESSORS_ONLN)
+  if result <= 0: result = 1
+