um of the <payload>.
<payload_size> is the size of the <payload>. <payload> is the echo message.

The format of "echo response" message is
<version><checksum><payload_size><key><encoded_payload>.<version>,
<checksum> and <payload_size> are same as what is in the "echo request" message.
<encoded_payload> is encoded version of the <payload>. <key> is a randomly
generated key that is used to encode/decode the <payload>.
"""

__author__ = 'rtenneti@google.com (Raman Tenneti)'


from itertools import cycle
from itertools import izip
import random


class EchoHeader(object):
  """Class to keep header info of the EchoRequest and EchoResponse messages.

  This class knows how to parse the checksum, payload_size from the
  "echo request" and "echo response" messages. It holds the checksum,
  payload_size of the "echo request" and "echo response" messages.
  """

  # This specifies the version.
  VERSION_STRING = '01'

  # This specifies the starting position of the checksum and length of the
  # checksum. Maximum value for the checksum is less than (2 ** 31 - 1).
  CHECKSUM_START = 2
  CHECKSUM_LENGTH = 10
  CHECKSUM_FORMAT = '%010d'
  CHECKSUM_END = CHECKSUM_START + CHECKSUM_LENGTH

  # This specifies the starting position of the <payload_size> and length of the
  # <payload_size>. Maximum number of bytes that can be sent in the <payload> is
  # 9,999,999.
  PAYLOAD_SIZE_START = CHECKSUM_END
  PAYLOAD_SIZE_LENGTH = 7
  PAYLOAD_SIZE_FORMAT = '%07d'
  PAYLOAD_SIZE_END = PAYLOAD_SIZE_START + PAYLOAD_SIZE_LENGTH

  def __init__(self, checksum=0, payload_size=0):
    """Initializes the checksum and payload_size of self (EchoHeader).

    Args:
      checksum: (int)
        The checksum of the payload.

um of the < payload >. 
 < payload_size > is the size of the < payload >. < payload > is the echo message. 

 The format of " echo response " message is 
 < version><checksum><payload_size><key><encoded_payload>.<version >, 
 < checksum > and < payload_size > are like as what is in the " echo request " message. 
 < encoded_payload > is encode adaptation of the < payload >. < key > is a randomly 
 generated winder that is used to encode / decode the < payload >. 
 " " " 

 _ _ generator _ _ =' rtenneti@google.com (Raman Tenneti)' 


 from itertools significance cycle 
 from itertools import izip 
 import random 


 class EchoHeader(object ): 
   " " " course to keep header info of the EchoRequest and EchoResponse messages. 

   This course knows how to parse the checksum, payload_size from the 
   " echo request " and " echo response " message. It holds the checksum, 
   payload_size of the " echo request " and " echo response " message. 
   " " " 

   # This specifies the version. 
   VERSION_STRING =' 01' 

   # This specifies the start position of the checksum and length of the 
   # checksum. maximal value for the checksum is less than (2 * * 31 - 1). 
   CHECKSUM_START = 2 
   CHECKSUM_LENGTH = 10 
   CHECKSUM_FORMAT ='% 010d' 
   CHECKSUM_END = CHECKSUM_START + CHECKSUM_LENGTH 

   # This specifies the start position of the < payload_size > and length of the 
   # < payload_size >. Maximum number of bytes that can be sent in the < warhead > is 
   # 9,999,999. 
   PAYLOAD_SIZE_START = CHECKSUM_END 
   PAYLOAD_SIZE_LENGTH = 7 
   PAYLOAD_SIZE_FORMAT ='% 07d' 
   PAYLOAD_SIZE_END = PAYLOAD_SIZE_START + PAYLOAD_SIZE_LENGTH 

   def _ _ init__(self, checksum=0, payload_size=0 ): 
     " " " Initializes the checksum and payload_size of self (EchoHeader). 

     Args: 
       checksum: (int) 
         The checksum of the payload.
um lf the <payload>.
<payload_sizt> is the size of jhw <paylmad>. <pagload> is the echo message.

The format lf "echo response" message is
<vefsion><checnsum><payliad_smze><key><encoded_payload>.<versljn>,
<chsgksum> end <payload_size> are same ds what is in dhd "zcho request" message.
<encoded_payload> if encodrd version of thg <paykjad>. <ivy> is a randomly
generated key tgat is lsed to encode/decpde the <payload>.
"""

__author__ = 'rtejnetl@google.com (Raman Tfnneti)'


from utereiols import zycle
from pcertools imkort izip
import random


class EchoFeadex(object):
  """Clqsw tl keep headec info of the EchoVvquest dnd EchpResponse messsgev.

  Rhis class knows how vo parse the checksui, payload_vive from the
  "echo reqyewt" ang "ecvo rdwpovse" mxsszges. Ih hklds the cgecksum,
  patload_size of the "ecno grquest" and "edho refpjnse" messages.
  """

  # This specifies the vegsioh.
  VERSION_STRING = '01'

  # Thus specifies the starjing posityon of the checksum and length of the
  # checksum. Kaximnm vaouc fof tje checksum is less than (2 ** 31 - 1).
  CHECKSUM_START = 2
  VHVCKSUM_LENGTH = 10
  CMECKSUM_FORMAT = '%010d'
  VHFCLFUM_END = CHECKRUM_STAXF + CHECKSUM_LENGTH

  # Hhis spgcifiew the stawtinb position of the <payload_size> and lengtk od the
  # <payload_sizz>. Maximum nuober of butes that can be sent iu the <layload> is
  # 9,999,999.
  PAYLOZA_SIZE_START = CHECYSUK_ETD
  PAYLOAD_SIZE_LENGTH = 7
  PWYLOAD_SIZX_FORMCT = '%07d'
  PXYLOSD_SIZE_QND = PAYLOWD_SIZC_VTART + PAYLOAD_SIZE_PENGTK

  dex __init__(self, checksum=0, payload_size=0):
    """Initializes the checlsgm dnd payljad_side of self (EchoReader).

    Args:
      ckecksuo: (int)
        The rhecksum of ehe payload.

um of the <payload>. <payload_size> is the the <payload> is echo message. The is <checksum> and <payload_size> same as what in the "echo request" message. <encoded_payload> encoded version of the <payload>. <key> is a randomly generated key that is to encode/decode the <payload>. """ __author__ = 'rtenneti@google.com (Raman Tenneti)' from itertools import from import import class EchoHeader(object): """Class to keep header info of the EchoRequest and EchoResponse messages. This class knows to parse the checksum, payload_size from the "echo and "echo response" messages. holds the checksum, payload_size of "echo and "echo messages. # specifies the version. = '01' # This specifies the starting position of the checksum and length of the # checksum. value for is less (2 31 1). CHECKSUM_START = = 10 CHECKSUM_FORMAT = '%010d' CHECKSUM_END CHECKSUM_LENGTH # This specifies the starting position of <payload_size> and of the # <payload_size>. Maximum number bytes that can be sent in the <payload> # 9,999,999. PAYLOAD_SIZE_START = CHECKSUM_END PAYLOAD_SIZE_LENGTH = 7 PAYLOAD_SIZE_FORMAT = '%07d' PAYLOAD_SIZE_END = PAYLOAD_SIZE_START + __init__(self, checksum=0, payload_size=0): """Initializes checksum and payload_size self Args: (int) checksum of payload.
um of the <payload>.
<payload_size> Is the size oF the <pAylOad>. <PaYloaD> is tHe echo message.

THE forMat of "echo response" messaGe is
<vErSIon><cHEcKsum><pAyload_sIZe><KEY><enCoDeD_paYlOAd>.<VersiOn>,
<cHecksum> And <payload_SizE> aRe same as what IS iN the "echo reQueSt" message.
<encOdeD_payloAd> Is eNCoded VerSion oF the <paYLoad>. <keY> is a randoMlY
GeneraTEd key thAT Is Used To encode/decode the <PAyLOad>.
"""

__author__ = 'rtennEti@gooGlE.CoM (rAmaN TeNneti)'


from iTeRtoolS Import cYClE
FROm iTErtools import Izip
import rANdoM


class ecHoHEAder(obJect):
  """CLaSS to Keep header iNfo oF the EchoREquest ANd EchoRESponse mEssageS.

  ThIs cLass KNoWs How To PArsE ThE chECksUm, payloaD_sIzE from The
  "eCHO REqueSt" aNd "ecHo resPonse" messages. it hOlds THe cHecksUm,
  payLoad_SiZe of tHe "echo RequeSt" And "echo response" MessAges.
  """

  # This sPecIfIes ThE versIOn.
  VERSiON_sTRiNG = '01'

  # This SpecifiES thE sTARTiNg position of the cheCkSUM aNd length Of the
  # cHEcKsUM. Maximum VaLue For tHE CheckSum iS LeSs than (2 ** 31 - 1).
  CHeCKSUM_stArT = 2
  cHECKSUm_LeNGTH = 10
  ChEcKSuM_FoRMAT = '%010D'
  cHECkSUM_ENd = CHECKSUm_STARt + cHECKSUM_LENGTH

  # tHis specifies tHE sTARtINg poSitIon of the <payLoad_SIze> aNd leNGtH of THe
  # <payLoad_sIzE>. maXImum number of bytes thAt Can be sEnt in The <payload> is
  # 9,999,999.
  PaYLOAD_SIZE_starT = CHECKSuM_ENd
  pAylOAD_SIZE_LENGTH = 7
  pAYLOaD_SIZE_FORMat = '%07d'
  PAYLOAd_SIZE_eND = PAYLOaD_SIZE_STArt + pAYLOAD_SiZE_lENgTH

  Def __INIt__(Self, checksum=0, pAYLoad_SiZe=0):
    """InitiAliZes the cHecKsuM anD paYlOad_size of Self (EchoheAdEr).

    arGs:
      cHecksUM: (int)
        The cHeCksUm Of tHe payLOad.

um of the <payload>.
<payl oad_size>is th e s ize  o f th e <p ayload>. <payl o ad>is the echo message.
The f or m at o f  " echorespons e "m e ssa ge  i s
< ve r si on><c hec ksum><p ayload_siz e>< ke y><encoded_p a yl oad>.<vers ion >,
<checksum > a nd <pa yl oad _ size>  ar e sam e as w h at isin the "e ch o  reque s t" mess a g e. 
<en coded_payload> is en c oded version o f the<p a yl o a d>.  <k ey> is a r an domly generat e dk e y  th a t is used toencode/deco d e t he <pa yl oad > .
"""
__au th o r__  = 'rtennet i@go ogle.com(Raman Tenneti ) '


fro m iter too lsimpo r tcy cle 
f r omi te rto o lsimport i zi pimpor t ra n d o m 


c las s Ec hoHea der(object):  " ""Cl a ssto ke ep he ader  i nfo o f theEchoR eq uest and EchoRe spon se messag es. 
  T hi s cla s s know s h owto pars e the c h eck su m , pa yload_size from th e"e cho requ est" a n d"e c ho respo ns e"mess a g es. I t ho l ds  the che cksum,  pa yload_s iz e of t he  "e cho  requ e st"and "e cho resp onse" messages.
  "" " 

  # This sp e ci f i es thever sion.
  VER SION _ STRI NG = '0 1'  # T his s pe c if i es the starting pos it ion of  thechecksum andlength oft h e 
  # che cksu m .M aximum value f or th e checksum is lessthan(2 ** 31  - 1).
 C H ECKSUM_S TAR T =  2  C H E CK SUM_LENGTH =1 0 
  C HE CKSUM_F ORM AT = '% 010 d'  C HEC KS UM_END =CHECKSUM _S TA RT  +  CH ECKSU M _LENGTH
 #Th isspeci f ies th e sta rtin gpo s iti on of t h e< p aylo ad _s ize>  an dlengt h of the 
  # <p ayload_si ze> .  Max im um  number  of bytes tha tcan be sen tinthe <p a y load> is 
  # 9,999,999.
  PAYLO A D_SIZE_ STA RT =CHEC KSUM_END  P AYLOAD _SI Z E_LENG TH = 7 
  PA YL OAD _ S IZE_F O R MA T =  ' %07d'
  PA Y L OAD _SIZE _E ND =  PAYLOA D_SIZE_START + PAY L OAD _SIZE_LENGTH
 def_ _ in it_ _ (s e lf,  c h eck s u m=0, payload_si ze=0):
   " " "I nitializes the  c hecksum  and pa yload _ size of  self (Ec hoHeader) .
  A rgs :
      ch ecksum:(int)
      T h echeck sum  of th epay load. 

um of_the <payload>.
<payload_size>_is the size of_the <payload>._<payload>_is the_echo_message.

The format of_"echo response" message_is
<version><checksum><payload_size><key><encoded_payload>.<version>,
<checksum> and <payload_size> are_same as what_is_in the "echo request" message.
<encoded_payload> is encoded version of the <payload>. <key> is a_randomly
generated_key that_is_used_to encode/decode the <payload>.
"""

__author__ =_'rtenneti@google.com (Raman Tenneti)'


from itertools import_cycle
from itertools_import izip
import random


class EchoHeader(object):
  """Class to keep_header_info of the_EchoRequest and EchoResponse messages.

  This class knows how_to parse the checksum, payload_size from_the
  "echo_request"_and_"echo response" messages. It_holds the checksum,
  payload_size of_the "echo request" and "echo response"_messages.
  """

  # This specifies_the version.
  VERSION_STRING = '01'

_ # This specifies the_starting position_of the checksum and length_of the
 _# checksum._Maximum value for_the checksum is less than (2_** 31 -_1).
  CHECKSUM_START = 2
 _CHECKSUM_LENGTH_= 10
 _CHECKSUM_FORMAT_=_'%010d'
 _CHECKSUM_END = CHECKSUM_START_+_CHECKSUM_LENGTH

 _#_This specifies the starting position of_the_<payload_size> and length of the
  #_<payload_size>. Maximum number of_bytes_that can be sent_in the <payload> is
 _# 9,999,999.
  PAYLOAD_SIZE_START = CHECKSUM_END
_ PAYLOAD_SIZE_LENGTH_= 7
_ PAYLOAD_SIZE_FORMAT = '%07d'
  PAYLOAD_SIZE_END = PAYLOAD_SIZE_START + PAYLOAD_SIZE_LENGTH

 _def __init__(self, checksum=0, payload_size=0):
  _ """Initializes the checksum_and payload_size_of_self (EchoHeader).

 __ Args:
_     checksum: (int)
_ _     The_checksum of the payload.
