new_contents: #!/usr/bin/env python
  
  # Copyright (c) 2013 ARM Limited
  # All rights reserved
  #
  # The license below extends only to copyright in the software and shall
  # not be construed as granting a license to any other intellectual
  # property including but not limited to intellectual property relating
  # to a hardware implementation of the functionality of the software
  # licensed hereunder.  You may use the software subject to the license
  # terms below provided that you ensure that this notice is replicated
  # unmodified and in its entirety in all distributions of the software,
  # modified or unmodified, in source code or in binary form.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met: redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer;
  # redistributions in binary form must reproduce the above copyright
  # notice, this list of conditions and the following disclaimer in the
  # documentation and/or other materials provided with the distribution;
  # neither the name of the copyright holders nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  # Copyright 2008 Google Inc.  All rights reserved.
  # http://code.google.com/p/protobuf/
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #     * Redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer.
  #     * Redistributions in binary form must reproduce the above
  # copyright notice, this list of conditions and the following disclaimer
  # in the documentation and/or other materials provided with the
  # distribution.
  #     * Neither the name of Google Inc. nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  # Authors: Andreas Hansson
  #
  
  # This script is used to migrate ASCII packet traces to the protobuf
  # format currently used in gem5. It assumes that protoc has been
  # executed and already generated the Python package for the packet
  # messages. This can be done manually using:
  # protoc --python_out=. --proto_path=src/proto src/proto/packet.proto
  #
  # The ASCII trace format uses one line per request on the format cmd,
  # addr, size, tick. For example:
  # r,128,64,4000
  # w,232123,64,500000
  # This trace reads 64 bytes from decimal address 128 at tick 4000,
  # then writes 64 bytes to address 232123 at tick 500000.
  #
  # This script can of course also be used as a template to convert
  # other trace formats into the gem5 protobuf format
  
  import struct
  import sys
  import packet_pb2
  
  def EncodeVarint(out_file, value):
    """
    The encoding of the Varint32 is copied from
    google.protobuf.internal.encoder and is only repeated here to
    avoid depending on the internal functions in the library.
    """
    bits = value & 0x7f
    value >>= 7
    while value:
      out_file.write(struct.pack('<B', 0x80|bits))
      bits = value & 0x7f
      value >>= 7
    out_file.write(struct.pack('<B', bits))
  
  def encodeMessage(out_file, message):
      """
      Encoded a message with the length prepended as a 32-bit varint.
      """
      out = message.SerializeToString()
      EncodeVarint(out_file, len(out))
      out_file.write(out)
  
  def main():
      if len(sys.argv) != 3:
          print "Usage: ", sys.argv[0], " <ASCII input> <protobuf output>"
          exit(-1)
  
      try:
          ascii_in = open(sys.argv[1], 'r')
      except IOError:
          print "Failed to open ", sys.argv[1], " for reading"
          exit(-1)
  
      try:
          proto_out = open(sys.argv[2], 'wb')
      except IOError:
          print "Failed to open ", sys.argv[2], " for writing"
          exit(-1)
  
      # Write the magic number in 4-byte Little Endian, similar to what
      # is done in src/proto/protoio.cc
      proto_out.write("gem5")
  
      # Add the packet header
      header = packet_pb2.PacketHeader()
      header.obj_id = "Converted ASCII trace " + sys.argv[1]
      # Assume the default tick rate
      header.tick_freq = 1000000000
      encodeMessage(proto_out, header)
  
      # For each line in the ASCII trace, create a packet message and
      # write it to the encoded output
      for line in ascii_in:
          cmd, addr, size, tick = line.split(',')
          packet = packet_pb2.Packet()
          packet.tick = long(tick)
          # ReadReq is 1 and WriteReq is 4 in src/mem/packet.hh Command enum
          packet.cmd = 1 if cmd == 'r' else 4
          packet.addr = long(addr)
          packet.size = int(size)
          encodeMessage(proto_out, packet)
  
      # We're done
      ascii_in.close()
      proto_out.close()
  
  if __name__ == "__main__":
      main()
  
subject: Add a utility script for encoding packet traces