text: #!/usr/bin/env python
  
  """ This module tries to retrieve as much platform-identifying data as
      possible. It makes this information available via function APIs.
  
      If called from the command line, it prints the platform
      information concatenated as single string to stdout. The output
      format is useable as part of a filename.
  
  """
  #    This module is maintained by Marc-Andre Lemburg <mal@egenix.com>.
  #    If you find problems, please submit bug reports/patches via the
  #    Python SourceForge Project Page and assign them to "lemburg".
  #
  #    Note: Please keep this module compatible to Python 1.5.2.
  #
  #    Still needed:
  #    * more support for WinCE
  #    * support for MS-DOS (PythonDX ?)
  #    * support for Amiga and other still unsupported platforms running Python
  #    * support for additional Linux distributions
  #
  #    Many thanks to all those who helped adding platform-specific
  #    checks (in no particular order):
  #
  #      Charles G Waldman, David Arnold, Gordon McMillan, Ben Darnell,
  #      Jeff Bauer, Cliff Crawford, Ivan Van Laningham, Josef
  #      Betancourt, Randall Hopper, Karl Putland, John Farrell, Greg
  #      Andruk, Just van Rossum, Thomas Heller, Mark R. Levinson, Mark
  #      Hammond, Bill Tutt, Hans Nowak, Uwe Zessin (OpenVMS support),
  #      Colin Kong, Trent Mick
  #
  #    History:
  #    1.0.2 - added more Windows support
  #    1.0.1 - reformatted to make doc.py happy
  #    1.0.0 - reformatted a bit and checked into Python CVS
  #    0.8.0 - added sys.version parser and various new access
  #            APIs (python_version(), python_compiler(), etc.)
  #    0.7.2 - fixed architecture() to use sizeof(pointer) where available
  #    0.7.1 - added support for Caldera OpenLinux
  #    0.7.0 - some fixes for WinCE; untabified the source file
  #    0.6.2 - support for OpenVMS - requires version 1.5.2-V006 or higher and
  #            vms_lib.getsyi() configured
  #    0.6.1 - added code to prevent 'uname -p' on platforms which are
  #            known not to support it
  #    0.6.0 - fixed win32_ver() to hopefully work on Win95,98,NT and Win2k;
  #            did some cleanup of the interfaces - some APIs have changed
  #    0.5.5 - fixed another type in the MacOS code... should have
  #            used more coffee today ;-)
  #    0.5.4 - fixed a few typos in the MacOS code
  #    0.5.3 - added experimental MacOS support; added better popen()
  #            workarounds in _syscmd_ver() -- still not 100% elegant
  #            though
  #    0.5.2 - fixed uname() to return '' instead of 'unknown' in all
  #            return values (the system uname command tends to return
  #            'unknown' instead of just leaving the field emtpy)
  #    0.5.1 - included code for slackware dist; added exception handlers
  #            to cover up situations where platforms don't have os.popen
  #            (e.g. Mac) or fail on socket.gethostname(); fixed libc
  #            detection RE
  #    0.5.0 - changed the API names referring to system commands to *syscmd*;
  #            added java_ver(); made syscmd_ver() a private
  #            API (was system_ver() in previous versions) -- use uname()
  #            instead; extended the win32_ver() to also return processor
  #            type information
  #    0.4.0 - added win32_ver() and modified the platform() output for WinXX
  #    0.3.4 - fixed a bug in _follow_symlinks()
  #    0.3.3 - fixed popen() and "file" command invokation bugs
  #    0.3.2 - added architecture() API and support for it in platform()
  #    0.3.1 - fixed syscmd_ver() RE to support Windows NT
  #    0.3.0 - added system alias support
  #    0.2.3 - removed 'wince' again... oh well.
  #    0.2.2 - added 'wince' to syscmd_ver() supported platforms
  #    0.2.1 - added cache logic and changed the platform string format
  #    0.2.0 - changed the API to use functions instead of module globals
  #            since some action take too long to be run on module import
  #    0.1.0 - first release
  #
  #    You can always get the latest version of this module at:
  #
  #             http://www.egenix.com/files/python/platform.py
  #
  #    If that URL should fail, try contacting the author.
  
  __copyright__ = """
      Copyright (c) 1999-2000, Marc-Andre Lemburg; mailto:mal@lemburg.com
      Copyright (c) 2000-2003, eGenix.com Software GmbH; mailto:info@egenix.com
  
      Permission to use, copy, modify, and distribute this software and its
      documentation for any purpose and without fee or royalty is hereby granted,
      provided that the above copyright notice appear in all copies and that
      both that copyright notice and this permission notice appear in
      supporting documentation or portions thereof, including modifications,
      that you make.
  
      EGENIX.COM SOFTWARE GMBH DISCLAIMS ALL WARRANTIES WITH REGARD TO
      THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
      FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
      INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
      FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
      NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
      WITH THE USE OR PERFORMANCE OF THIS SOFTWARE !
  
  """
  
  __version__ = '1.0.2'
  
  import sys,string,os,re
  
  ### Platform specific APIs
  
  _libc_search = re.compile(r'(__libc_init)'
                            '|'
                            '(GLIBC_([0-9.]+))'
                            '|'
                            '(libc(_\w+)?\.so(?:\.(\d[0-9.]*))?)')
  
  def libc_ver(executable=sys.executable,lib='',version='',
  
               chunksize=2048):
  
      """ Tries to determine the libc version that the file executable
          (which defaults to the Python interpreter) is linked against.
  
          Returns a tuple of strings (lib,version) which default to the
          given parameters in case the lookup fails.
  
          Note that the function has intimate knowledge of how different
          libc versions add symbols to the executable and thus is probably
          only useable for executables compiled using gcc.
  
          The file is read and scanned in chunks of chunksize bytes.
  
      """
      f = open(executable,'rb')
      binary = f.read(chunksize)
      pos = 0
      while 1:
          m = _libc_search.search(binary,pos)
          if not m:
              binary = f.read(chunksize)
              if not binary:
                  break
              pos = 0
              continue
          libcinit,glibc,glibcversion,so,threads,soversion = m.groups()
          if libcinit and not lib:
              lib = 'libc'
          elif glibc:
              if lib != 'glibc':
                  lib = 'glibc'
                  version = glibcversion
              elif glibcversion > version:
                  version = glibcversion
          elif so:
              if lib != 'glibc':
                  lib = 'libc'
                  if soversion > version:
                      version = soversion
                  if threads and version[-len(threads):] != threads:
                      version = version + threads
          pos = m.end()
      f.close()
      return lib,version
  
  def _dist_try_harder(distname,version,id):
  
      """ Tries some special tricks to get the distribution
          information in case the default method fails.
  
          Currently supports older SuSE Linux, Caldera OpenLinux and
          Slackware Linux distributions.
  
      """
      if os.path.exists('/var/adm/inst-log/info'):
          # SuSE Linux stores distribution information in that file
          info = open('/var/adm/inst-log/info').readlines()
          distname = 'SuSE'
          for line in info:
              tv = string.split(line)
              if len(tv) == 2:
                  tag,value = tv
              else:
                  continue
              if tag == 'MIN_DIST_VERSION':
                  version = string.strip(value)
              elif tag == 'DIST_IDENT':
                  values = string.split(value,'-')
                  id = values[2]
          return distname,version,id
  
      if os.path.exists('/etc/.installed'):
          # Caldera OpenLinux has some infos in that file (thanks to Colin Kong)
          info = open('/etc/.installed').readlines()
          for line in info:
              pkg = string.split(line,'-')
              if len(pkg) >= 2 and pkg[0] == 'OpenLinux':
                  # XXX does Caldera support non Intel platforms ? If yes,
                  #     where can we find the needed id ?
                  return 'OpenLinux',pkg[1],id
  
      if os.path.isdir('/usr/lib/setup'):
          # Check for slackware verson tag file (thanks to Greg Andruk)
          verfiles = os.listdir('/usr/lib/setup')
          for n in range(len(verfiles)-1, -1, -1):
              if verfiles[n][:14] != 'slack-version-':
                  del verfiles[n]
          if verfiles:
              verfiles.sort()
              distname = 'slackware'
              version = verfiles[-1][14:]
              return distname,version,id
  
      return distname,version,id
  
  _release_filename = re.compile(r'(\w+)[-_](release|version)')
  _release_version = re.compile(r'([\d.]+)[^(]*(?:\((.+)\))?')
  
  _distributor_id_file_re = re.compile("(?:DISTRIB_ID\s*=)\s*(.*)", re.I)
  _release_file_re = re.compile("(?:DISTRIB_RELEASE\s*=)\s*(.*)", re.I)
  _codename_file_re = re.compile("(?:DISTRIB_CODENAME\s*=)\s*(.*)", re.I)
  
  def dist(distname='',version='',id='',
  
           supported_dists=('SuSE','debian','redhat','mandrake')):
  
      """ Tries to determine the name of the Linux OS distribution name.
  
          The function first looks for a distribution release file in
          /etc and then reverts to _dist_try_harder() in case no
          suitable files are found.
  
          Returns a tuple (distname,version,id) which default to the
          args given as parameters.
  
      """
      # check for the Debian/Ubuntu /etc/lsb-release file first, needed so
      # that the distribution doesn't get identified as Debian.
      try:
          etclsbrel = open("/etc/lsb-release", "rU")
          for line in etclsbrel:
              m = _distributor_id_file_re.search(line)
              if m:
                  _u_distname = m.group(1).strip()
              m = _release_file_re.search(line)
              if m:
                  _u_version = m.group(1).strip()
              m = _codename_file_re.search(line)
              if m:
                  _u_id = m.group(1).strip()
          if _u_distname and _u_version:
              return (_u_distname, _u_version, _u_id)
      except (EnvironmentError, UnboundLocalError):
              pass
  
      try:
          etc = os.listdir('/etc')
      except os.error:
          # Probably not a Unix system
          return distname,version,id
  
      if os.path.exists('/etc/lsb-release'):
          for line in open('/etc/lsb-release'):
              line = line.strip()
              if not line:
                  continue
              var, arg = line.split('=', 1)
              if var.startswith('DISTRIB_'):
                  var = var[8:]
                  if arg.startswith('"') and arg.endswith('"'):
                      arg = arg[1:-1]
                  if var == 'ID':
                      distname = arg
                  elif var == 'RELEASE':
                      version = arg
                  elif var == 'CODENAME':
                      id = arg
          return distname,version,id
  
      for file in etc:
          m = _release_filename.match(file)
          if m:
              _distname,dummy = m.groups()
              if _distname in supported_dists:
                  distname = _distname
                  break
      else:
          return _dist_try_harder(distname,version,id)
      f = open('/etc/'+file,'r')
      firstline = f.readline()
      f.close()
      m = _release_version.search(firstline)
      if m:
          _version,_id = m.groups()
          if _version:
              version = _version
          if _id:
              id = _id
      else:
          # Unkown format... take the first two words
          l = string.split(string.strip(firstline))
          if l:
              version = l[0]
              if len(l) > 1:
                  id = l[1]
      return distname,version,id
  
  class _popen:
  
      """ Fairly portable (alternative) popen implementation.
  
          This is mostly needed in case os.popen() is not available, or
          doesn't work as advertised, e.g. in Win9X GUI programs like
          PythonWin or IDLE.
  
          Writing to the pipe is currently not supported.
  
      """
      tmpfile = ''
      pipe = None
      bufsize = None
      mode = 'r'
  
      def __init__(self,cmd,mode='r',bufsize=None):
  
          if mode != 'r':
              raise ValueError,'popen()-emulation only supports read mode'
          import tempfile
          self.tmpfile = tmpfile = tempfile.mktemp()
          os.system(cmd + ' > %s' % tmpfile)
          self.pipe = open(tmpfile,'rb')
          self.bufsize = bufsize
          self.mode = mode
  
      def read(self):
  
          return self.pipe.read()
  
      def readlines(self):
  
          if self.bufsize is not None:
              return self.pipe.readlines()
  
      def close(self,
  
                remove=os.unlink,error=os.error):
  
          if self.pipe:
              rc = self.pipe.close()
          else:
              rc = 255
          if self.tmpfile:
              try:
                  remove(self.tmpfile)
              except error:
                  pass
          return rc
  
      # Alias
      __del__ = close
  
  def popen(cmd, mode='r', bufsize=None):
  
      """ Portable popen() interface.
      """
      # Find a working popen implementation preferring win32pipe.popen
      # over os.popen over _popen
      popen = None
      if os.environ.get('OS','') == 'Windows_NT':
          # On NT win32pipe should work; on Win9x it hangs due to bugs
          # in the MS C lib (see MS KnowledgeBase article Q150956)
          try:
              import win32pipe
          except ImportError:
              pass
          else:
              popen = win32pipe.popen
      if popen is None:
          if hasattr(os,'popen'):
              popen = os.popen
              # Check whether it works... it doesn't in GUI programs
              # on Windows platforms
              if sys.platform == 'win32': # XXX Others too ?
                  try:
                      popen('')
                  except os.error:
                      popen = _popen
          else:
              popen = _popen
      if bufsize is None:
          return popen(cmd,mode)
      else:
          return popen(cmd,mode,bufsize)
  
  def _norm_version(version,build=''):
  
      """ Normalize the version and build strings and return a single
          vesion string using the format major.minor.build (or patchlevel).
      """
      l = string.split(version,'.')
      if build:
          l.append(build)
      try:
          ints = map(int,l)
      except ValueError:
          strings = l
      else:
          strings = map(str,ints)
      version = string.join(strings[:3],'.')
      return version
  
  _ver_output = re.compile(r'(?:([\w ]+) ([\w.]+) '
                           '.*'
                           'Version ([\d.]+))')
  
  def _syscmd_ver(system='',release='',version='',
  
                 supported_platforms=('win32','win16','dos','os2')):
  
      """ Tries to figure out the OS version used and returns
          a tuple (system,release,version).
  
          It uses the "ver" shell command for this which is known
          to exists on Windows, DOS and OS/2. XXX Others too ?
  
          In case this fails, the given parameters are used as
          defaults.
  
      """
      if sys.platform not in supported_platforms:
          return system,release,version
  
      # Try some common cmd strings
      for cmd in ('ver','command /c ver','cmd /c ver'):
          try:
              pipe = popen(cmd)
              info = pipe.read()
              if pipe.close():
                  raise os.error,'command failed'
              # XXX How can I supress shell errors from being written
              #     to stderr ?
          except os.error,why:
              #print 'Command %s failed: %s' % (cmd,why)
              continue
          except IOError,why:
              #print 'Command %s failed: %s' % (cmd,why)
              continue
          else:
              break
      else:
          return system,release,version
  
      # Parse the output
      info = string.strip(info)
      m = _ver_output.match(info)
      if m:
          system,release,version = m.groups()
          # Strip trailing dots from version and release
          if release[-1] == '.':
              release = release[:-1]
          if version[-1] == '.':
              version = version[:-1]
          # Normalize the version and build strings (eliminating additional
          # zeros)
          version = _norm_version(version)
      return system,release,version
  
  def _win32_getvalue(key,name,default=''):
  
      """ Read a value for name from the registry key.
  
          In case this fails, default is returned.
  
      """
      from win32api import RegQueryValueEx
      try:
          return RegQueryValueEx(key,name)
      except:
          return default
  
  def win32_ver(release='',version='',csd='',ptype=''):
  
      """ Get additional version information from the Windows Registry
          and return a tuple (version,csd,ptype) referring to version
          number, CSD level and OS type (multi/single
          processor).
  
          As a hint: ptype returns 'Uniprocessor Free' on single
          processor NT machines and 'Multiprocessor Free' on multi
          processor machines. The 'Free' refers to the OS version being
          free of debugging code. It could also state 'Checked' which
          means the OS version uses debugging code, i.e. code that
          checks arguments, ranges, etc. (Thomas Heller).
  
          Note: this function only works if Mark Hammond's win32
          package is installed and obviously only runs on Win32
          compatible platforms.
  
      """
      # XXX Is there any way to find out the processor type on WinXX ?
      # XXX Is win32 available on Windows CE ?
      #
      # Adapted from code posted by Karl Putland to comp.lang.python.
      #
      # The mappings between reg. values and release names can be found
      # here: http://msdn.microsoft.com/library/en-us/sysinfo/base/osversioninfo_str.asp
  
      # Import the needed APIs
      try:
          import win32api
      except ImportError:
          return release,version,csd,ptype
      from win32api import RegQueryValueEx,RegOpenKeyEx,RegCloseKey,GetVersionEx
      from win32con import HKEY_LOCAL_MACHINE,VER_PLATFORM_WIN32_NT,\
                           VER_PLATFORM_WIN32_WINDOWS
  
      # Find out the registry key and some general version infos
      maj,min,buildno,plat,csd = GetVersionEx()
      version = '%i.%i.%i' % (maj,min,buildno & 0xFFFF)
      if csd[:13] == 'Service Pack ':
          csd = 'SP' + csd[13:]
      if plat == VER_PLATFORM_WIN32_WINDOWS:
          regkey = 'SOFTWARE\\Microsoft\\Windows\\CurrentVersion'
          # Try to guess the release name
          if maj == 4:
              if min == 0:
                  release = '95'
              elif min == 10:
                  release = '98'
              elif min == 90:
                  release = 'Me'
              else:
                  release = 'postMe'
          elif maj == 5:
              release = '2000'
      elif plat == VER_PLATFORM_WIN32_NT:
          regkey = 'SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion'
          if maj <= 4:
              release = 'NT'
          elif maj == 5:
              if min == 0:
                  release = '2000'
              elif min == 1:
                  release = 'XP'
              elif min == 2:
                  release = '2003Server'
              else:
                  release = 'post2003'
      else:
          if not release:
              # E.g. Win3.1 with win32s
              release = '%i.%i' % (maj,min)
          return release,version,csd,ptype
  
      # Open the registry key
      try:
          keyCurVer = RegOpenKeyEx(HKEY_LOCAL_MACHINE,regkey)
          # Get a value to make sure the key exists...
          RegQueryValueEx(keyCurVer,'SystemRoot')
      except:
          return release,version,csd,ptype
  
      # Parse values
      #subversion = _win32_getvalue(keyCurVer,
      #                            'SubVersionNumber',
      #                            ('',1))[0]
      #if subversion:
      #   release = release + subversion # 95a, 95b, etc.
      build = _win32_getvalue(keyCurVer,
                              'CurrentBuildNumber',
                              ('',1))[0]
      ptype = _win32_getvalue(keyCurVer,
                             'CurrentType',
                             (ptype,1))[0]
  
      # Normalize version
      version = _norm_version(version,build)
  
      # Close key
      RegCloseKey(keyCurVer)
      return release,version,csd,ptype
  
  def _mac_ver_lookup(selectors,default=None):
  
      from gestalt import gestalt
      import MacOS
      l = []
      append = l.append
      for selector in selectors:
          try:
              append(gestalt(selector))
          except (RuntimeError, MacOS.Error):
              append(default)
      return l
  
  def _bcd2str(bcd):
  
      return hex(bcd)[2:]
  
  def mac_ver(release='',versioninfo=('','',''),machine=''):
  
      """ Get MacOS version information and return it as tuple (release,
          versioninfo, machine) with versioninfo being a tuple (version,
          dev_stage, non_release_version).
  
          Entries which cannot be determined are set to the paramter values
          which default to ''. All tuple entries are strings.
  
          Thanks to Mark R. Levinson for mailing documentation links and
          code examples for this function. Documentation for the
          gestalt() API is available online at:
  
             http://www.rgaros.nl/gestalt/
  
      """
      # Check whether the version info module is available
      try:
          import gestalt
          import MacOS
      except ImportError:
          return release,versioninfo,machine
      # Get the infos
      sysv,sysu,sysa = _mac_ver_lookup(('sysv','sysu','sysa'))
      # Decode the infos
      if sysv:
          major = (sysv & 0xFF00) >> 8
          minor = (sysv & 0x00F0) >> 4
          patch = (sysv & 0x000F)
          release = '%s.%i.%i' % (_bcd2str(major),minor,patch)
      if sysu:
          major =  int((sysu & 0xFF000000L) >> 24)
          minor =  (sysu & 0x00F00000) >> 20
          bugfix = (sysu & 0x000F0000) >> 16
          stage =  (sysu & 0x0000FF00) >> 8
          nonrel = (sysu & 0x000000FF)
          version = '%s.%i.%i' % (_bcd2str(major),minor,bugfix)
          nonrel = _bcd2str(nonrel)
          stage = {0x20:'development',
                   0x40:'alpha',
                   0x60:'beta',
                   0x80:'final'}.get(stage,'')
          versioninfo = (version,stage,nonrel)
      if sysa:
          machine = {0x1: '68k',
                     0x2: 'PowerPC'}.get(sysa,'')
      return release,versioninfo,machine
  
  def _java_getprop(name,default):
  
      from java.lang import System
      try:
          return System.getProperty(name)
      except:
          return default
  
  def java_ver(release='',vendor='',vminfo=('','',''),osinfo=('','','')):
  
      """ Version interface for Jython.
  
          Returns a tuple (release,vendor,vminfo,osinfo) with vminfo being
          a tuple (vm_name,vm_release,vm_vendor) and osinfo being a
          tuple (os_name,os_version,os_arch).
  
          Values which cannot be determined are set to the defaults
          given as parameters (which all default to '').
  
      """
      # Import the needed APIs
      try:
          import java.lang
      except ImportError:
          return release,vendor,vminfo,osinfo
  
      vendor = _java_getprop('java.vendor',vendor)
      release = _java_getprop('java.version',release)
      vm_name,vm_release,vm_vendor = vminfo
      vm_name = _java_getprop('java.vm.name',vm_name)
      vm_vendor = _java_getprop('java.vm.vendor',vm_vendor)
      vm_release = _java_getprop('java.vm.version',vm_release)
      vminfo = vm_name,vm_release,vm_vendor
      os_name,os_version,os_arch = osinfo
      os_arch = _java_getprop('java.os.arch',os_arch)
      os_name = _java_getprop('java.os.name',os_name)
      os_version = _java_getprop('java.os.version',os_version)
      osinfo = os_name,os_version,os_arch
  
      return release,vendor,vminfo,osinfo
  
  ### System name aliasing
  
  def system_alias(system,release,version):
  
      """ Returns (system,release,version) aliased to common
          marketing names used for some systems.
  
          It also does some reordering of the information in some cases
          where it would otherwise cause confusion.
  
      """
      if system == 'Rhapsody':
          # Apple's BSD derivative
          # XXX How can we determine the marketing release number ?
          return 'MacOS X Server',system+release,version
  
      elif system == 'SunOS':
          # Sun's OS
          if release < '5':
              # These releases use the old name SunOS
              return system,release,version
          # Modify release (marketing release = SunOS release - 3)
          l = string.split(release,'.')
          if l:
              try:
                  major = int(l[0])
              except ValueError:
                  pass
              else:
                  major = major - 3
                  l[0] = str(major)
                  release = string.join(l,'.')
          if release < '6':
              system = 'Solaris'
          else:
              # XXX Whatever the new SunOS marketing name is...
              system = 'Solaris'
  
      elif system == 'IRIX64':
          # IRIX reports IRIX64 on platforms with 64-bit support; yet it
          # is really a version and not a different platform, since 32-bit
          # apps are also supported..
          system = 'IRIX'
          if version:
              version = version + ' (64bit)'
          else:
              version = '64bit'
  
      elif system in ('win32','win16'):
          # In case one of the other tricks
          system = 'Windows'
  
      return system,release,version
  
  ### Various internal helpers
  
  def _platform(*args):
  
      """ Helper to format the platform string in a filename
          compatible format e.g. "system-version-machine".
      """
      # Format the platform string
      platform = string.join(
          map(string.strip,
              filter(len,args)),
          '-')
  
      # Cleanup some possible filename obstacles...
      replace = string.replace
      platform = replace(platform,' ','_')
      platform = replace(platform,'/','-')
      platform = replace(platform,'\\','-')
      platform = replace(platform,':','-')
      platform = replace(platform,';','-')
      platform = replace(platform,'"','-')
      platform = replace(platform,'(','-')
      platform = replace(platform,')','-')
  
      # No need to report 'unknown' information...
      platform = replace(platform,'unknown','')
  
      # Fold '--'s and remove trailing '-'
      while 1:
          cleaned = replace(platform,'--','-')
          if cleaned == platform:
              break
          platform = cleaned
      while platform[-1] == '-':
          platform = platform[:-1]
  
      return platform
  
  def _node(default=''):
  
      """ Helper to determine the node name of this machine.
      """
      try:
          import socket
      except ImportError:
          # No sockets...
          return default
      try:
          return socket.gethostname()
      except socket.error:
          # Still not working...
          return default
  
  # os.path.abspath is new in Python 1.5.2:
  if not hasattr(os.path,'abspath'):
  
      def _abspath(path,
  
                   isabs=os.path.isabs,join=os.path.join,getcwd=os.getcwd,
                   normpath=os.path.normpath):
  
          if not isabs(path):
              path = join(getcwd(), path)
          return normpath(path)
  
  else:
  
      _abspath = os.path.abspath
  
  def _follow_symlinks(filepath):
  
      """ In case filepath is a symlink, follow it until a
          real file is reached.
      """
      filepath = _abspath(filepath)
      while os.path.islink(filepath):
          filepath = os.path.normpath(
              os.path.join(filepath,os.readlink(filepath)))
      return filepath
  
  def _syscmd_uname(option,default=''):
  
      """ Interface to the system's uname command.
      """
      if sys.platform in ('dos','win32','win16','os2'):
          # XXX Others too ?
          return default
      try:
          f = os.popen('uname %s 2> /dev/null' % option)
      except (AttributeError,os.error):
          return default
      output = string.strip(f.read())
      rc = f.close()
      if not output or rc:
          return default
      else:
          return output
  
  def _syscmd_file(target,default=''):
  
      """ Interface to the system's file command.
  
          The function uses the -b option of the file command to have it
          ommit the filename in its output and if possible the -L option
          to have the command follow symlinks. It returns default in
          case the command should fail.
  
      """
      target = _follow_symlinks(target)
      try:
          f = os.popen('file %s 2> /dev/null' % target)
      except (AttributeError,os.error):
          return default
      output = string.strip(f.read())
      rc = f.close()
      if not output or rc:
          return default
      else:
          return output
  
  ### Information about the used architecture
  
  # Default values for architecture; non-empty strings override the
  # defaults given as parameters
  _default_architecture = {
      'win32': ('','WindowsPE'),
      'win16': ('','Windows'),
      'dos': ('','MSDOS'),
  }
  
  _architecture_split = re.compile(r'[\s,]').split
  
  def architecture(executable=sys.executable,bits='',linkage=''):
  
      """ Queries the given executable (defaults to the Python interpreter
          binary) for various architecture information.
  
          Returns a tuple (bits,linkage) which contains information about
          the bit architecture and the linkage format used for the
          executable. Both values are returned as strings.
  
          Values that cannot be determined are returned as given by the
          parameter presets. If bits is given as '', the sizeof(pointer)
          (or sizeof(long) on Python version < 1.5.2) is used as
          indicator for the supported pointer size.
  
          The function relies on the system's "file" command to do the
          actual work. This is available on most if not all Unix
          platforms. On some non-Unix platforms where the "file" command
          does not exist and the executable is set to the Python interpreter
          binary defaults from _default_architecture are used.
  
      """
      # Use the sizeof(pointer) as default number of bits if nothing
      # else is given as default.
      if not bits:
          import struct
          try:
              size = struct.calcsize('P')
          except struct.error:
              # Older installations can only query longs
              size = struct.calcsize('l')
          bits = str(size*8) + 'bit'
  
      # Get data from the 'file' system command
      output = _syscmd_file(executable,'')
  
      if not output and \
         executable == sys.executable:
          # "file" command did not return anything; we'll try to provide
          # some sensible defaults then...
          if _default_architecture.has_key(sys.platform):
              b,l = _default_architecture[sys.platform]
              if b:
                  bits = b
              if l:
                  linkage = l
          return bits,linkage
  
      # Split the output into a list of strings omitting the filename
      fileout = _architecture_split(output)[1:]
  
      if 'executable' not in fileout:
          # Format not supported
          return bits,linkage
  
      # Bits
      if '32-bit' in fileout:
          bits = '32bit'
      elif 'N32' in fileout:
          # On Irix only
          bits = 'n32bit'
      elif '64-bit' in fileout:
          bits = '64bit'
  
      # Linkage
      if 'ELF' in fileout:
          linkage = 'ELF'
      elif 'PE' in fileout:
          # E.g. Windows uses this format
          if 'Windows' in fileout:
              linkage = 'WindowsPE'
          else:
              linkage = 'PE'
      elif 'COFF' in fileout:
          linkage = 'COFF'
      elif 'MS-DOS' in fileout:
          linkage = 'MSDOS'
      else:
          # XXX the A.OUT format also falls under this class...
          pass
  
      return bits,linkage
  
  ### Portable uname() interface
  
  _uname_cache = None
  
  def uname():
  
      """ Fairly portable uname interface. Returns a tuple
          of strings (system,node,release,version,machine,processor)
          identifying the underlying platform.
  
          Note that unlike the os.uname function this also returns
          possible processor information as an additional tuple entry.
  
          Entries which cannot be determined are set to ''.
  
      """
      global _uname_cache
  
      if _uname_cache is not None:
          return _uname_cache
  
      # Get some infos from the builtin os.uname API...
      try:
          system,node,release,version,machine = os.uname()
  
      except AttributeError:
          # Hmm, no uname... we'll have to poke around the system then.
          system = sys.platform
          release = ''
          version = ''
          node = _node()
          machine = ''
          processor = ''
          use_syscmd_ver = 1
  
          # Try win32_ver() on win32 platforms
          if system == 'win32':
              release,version,csd,ptype = win32_ver()
              if release and version:
                  use_syscmd_ver = 0
  
          # Try the 'ver' system command available on some
          # platforms
          if use_syscmd_ver:
              system,release,version = _syscmd_ver(system)
  
          # In case we still don't know anything useful, we'll try to
          # help ourselves
          if system in ('win32','win16'):
              if not version:
                  if system == 'win32':
                      version = '32bit'
                  else:
                      version = '16bit'
              system = 'Windows'
  
          elif system[:4] == 'java':
              release,vendor,vminfo,osinfo = java_ver()
              system = 'Java'
              version = string.join(vminfo,', ')
              if not version:
                  version = vendor
  
          elif os.name == 'mac':
              release,(version,stage,nonrel),machine = mac_ver()
              system = 'MacOS'
  
      else:
          # System specific extensions
          if system == 'OpenVMS':
              # OpenVMS seems to have release and version mixed up
              if not release or release == '0':
                  release = version
                  version = ''
              # Get processor information
              try:
                  import vms_lib
              except ImportError:
                  pass
              else:
                  csid, cpu_number = vms_lib.getsyi('SYI$_CPU',0)
                  if (cpu_number >= 128):
                      processor = 'Alpha'
                  else:
                      processor = 'VAX'
          else:
              # Get processor information from the uname system command
              processor = _syscmd_uname('-p','')
  
      # 'unknown' is not really any useful as information; we'll convert
      # it to '' which is more portable
      if system == 'unknown':
          system = ''
      if node == 'unknown':
          node = ''
      if release == 'unknown':
          release = ''
      if version == 'unknown':
          version = ''
      if machine == 'unknown':
          machine = ''
      if processor == 'unknown':
          processor = ''
      _uname_cache = system,node,release,version,machine,processor
      return _uname_cache
  
  ### Direct interfaces to some of the uname() return values
  
  def system():
  
      """ Returns the system/OS name, e.g. 'Linux', 'Windows' or 'Java'.
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname()[0]
  
  def node():
  
      """ Returns the computer's network name (which may not be fully
          qualified)
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname()[1]
  
  def release():
  
      """ Returns the system's release, e.g. '2.2.0' or 'NT'
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname()[2]
  
  def version():
  
      """ Returns the system's release version, e.g. '#3 on degas'
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname()[3]
  
  def machine():
  
      """ Returns the machine type, e.g. 'i386'
  
          An empty string is returned if the value cannot be determined.
  
      """
      return uname()[4]
  
  def processor():
  
      """ Returns the (true) processor name, e.g. 'amdk6'
  
          An empty string is returned if the value cannot be
          determined. Note that many platforms do not provide this
          information or simply return the same value as for machine(),
          e.g.  NetBSD does this.
  
      """
      return uname()[5]
  
  ### Various APIs for extracting information from sys.version
  
  _sys_version_parser = re.compile(r'([\w.+]+)\s*'
                                    '\(#(\d+),\s*([\w ]+),\s*([\w :]+)\)\s*'
                                    '\[([^\]]+)\]?')
  _sys_version_cache = None
  
  def _sys_version():
  
      """ Returns a parsed version of Python's sys.version as tuple
          (version, buildno, builddate, compiler) referring to the Python
          version, build number, build date/time as string and the compiler
          identification string.
  
          Note that unlike the Python sys.version, the returned value
          for the Python version will always include the patchlevel (it
          defaults to '.0').
  
      """
      global _sys_version_cache
  
      if _sys_version_cache is not None:
          return _sys_version_cache
      version, buildno, builddate, buildtime, compiler = \
               _sys_version_parser.match(sys.version).groups()
      buildno = int(buildno)
      builddate = builddate + ' ' + buildtime
      l = string.split(version, '.')
      if len(l) == 2:
          l.append('0')
          version = string.join(l, '.')
      _sys_version_cache = (version, buildno, builddate, compiler)
      return _sys_version_cache
  
  def python_version():
  
      """ Returns the Python version as string 'major.minor.patchlevel'
  
          Note that unlike the Python sys.version, the returned value
          will always include the patchlevel (it defaults to 0).
  
      """
      return _sys_version()[0]
  
  def python_version_tuple():
  
      """ Returns the Python version as tuple (major, minor, patchlevel)
          of strings.
  
          Note that unlike the Python sys.version, the returned value
          will always include the patchlevel (it defaults to 0).
  
      """
      return string.split(_sys_version()[0], '.')
  
  def python_build():
  
      """ Returns a tuple (buildno, builddate) stating the Python
          build number and date as strings.
  
      """
      return _sys_version()[1:3]
  
  def python_compiler():
  
      """ Returns a string identifying the compiler used for compiling
          Python.
  
      """
      return _sys_version()[3]
  
  ### The Opus Magnum of platform strings :-)
  
  _platform_cache = {}
  
  def platform(aliased=0, terse=0):
  
      """ Returns a single string identifying the underlying platform
          with as much useful information as possible (but no more :).
  
          The output is intended to be human readable rather than
          machine parseable. It may look different on different
          platforms and this is intended.
  
          If "aliased" is true, the function will use aliases for
          various platforms that report system names which differ from
          their common names, e.g. SunOS will be reported as
          Solaris. The system_alias() function is used to implement
          this.
  
          Setting terse to true causes the function to return only the
          absolute minimum information needed to identify the platform.
  
      """
      result = _platform_cache.get((aliased, terse), None)
      if result is not None:
          return result
  
      # Get uname information and then apply platform specific cosmetics
      # to it...
      system,node,release,version,machine,processor = uname()
      if machine == processor:
          processor = ''
      if aliased:
          system,release,version = system_alias(system,release,version)
  
      if system == 'Windows':
          # MS platforms
          rel,vers,csd,ptype = win32_ver(version)
          if terse:
              platform = _platform(system,release)
          else:
              platform = _platform(system,release,version,csd)
  
      elif system in ('Linux',):
          # Linux based systems
          distname,distversion,distid = dist('')
          if distname and not terse:
              platform = _platform(system,release,machine,processor,
                                   'with',
                                   distname,distversion,distid)
          else:
              # If the distribution name is unknown check for libc vs. glibc
              libcname,libcversion = libc_ver(sys.executable)
              platform = _platform(system,release,machine,processor,
                                   'with',
                                   libcname+libcversion)
      elif system == 'Java':
          # Java platforms
          r,v,vminfo,(os_name,os_version,os_arch) = java_ver()
          if terse:
              platform = _platform(system,release,version)
          else:
              platform = _platform(system,release,version,
                                   'on',
                                   os_name,os_version,os_arch)
  
      elif system == 'MacOS':
          # MacOS platforms
          if terse:
              platform = _platform(system,release)
          else:
              platform = _platform(system,release,machine)
  
      else:
          # Generic handler
          if terse:
              platform = _platform(system,release)
          else:
              bits,linkage = architecture(sys.executable)
              platform = _platform(system,release,machine,processor,bits,linkage)
  
      _platform_cache[(aliased, terse)] = platform
      return platform
  
  ### Command line interface
  
  if __name__ == '__main__':
      # Default is to print the aliased verbose platform string
      terse = ('terse' in sys.argv or '--terse' in sys.argv)
      aliased = (not 'nonaliased' in sys.argv and not '--nonaliased' in sys.argv)
      print platform(aliased,terse)
      sys.exit(0)
  