Package ais :: Module sls_header
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Source Code for Module ais.sls_header

  1  #!/usr/bin/env python 
  2   
  3  __version__ = '$Revision: 4791 $'.split()[1] 
  4  __date__ = '$Date: 2007-01-02 $'.split()[1] 
  5  __author__ = 'xmlbinmsg' 
  6   
  7  __doc__=''' 
  8   
  9  Autogenerated python functions to serialize/deserialize binary messages. 
 10   
 11  Generated by: ./aisxmlbinmsg2py.py 
 12   
 13  Need to then wrap these functions with the outer AIS packet and then 
 14  convert the whole binary blob to a NMEA string.  Those functions are 
 15  not currently provided in this file. 
 16   
 17  serialize: python to ais binary 
 18  deserialize: ais binary to python 
 19   
 20  The generated code uses translators.py, binary.py, and aisstring.py 
 21  which should be packaged with the resulting files. 
 22   
 23   
 24  @requires: U{epydoc<http://epydoc.sourceforge.net/>} > 3.0alpha3 
 25  @requires: U{BitVector<http://cheeseshop.python.org/pypi/BitVector>} 
 26   
 27  @author: '''+__author__+''' 
 28  @version: ''' + __version__ +''' 
 29  @var __date__: Date of last svn commit 
 30  @undocumented: __version__ __author__ __doc__ parser 
 31  @status: under development 
 32  @license: Generated code has no license 
 33  ''' 
 34   
 35  import sys 
 36  from decimal import Decimal 
 37  from BitVector import BitVector 
 38   
 39  import binary, aisstring 
 40   
 41  # FIX: check to see if these will be needed 
 42  TrueBV  = BitVector(bitstring="1") 
 43  "Why always rebuild the True bit?  This should speed things up a bunch" 
 44  FalseBV = BitVector(bitstring="0") 
 45  "Why always rebuild the False bit?  This should speed things up a bunch" 
 46   
 47   
48 -def encode(params, validate=False):
49 '''Create a sls_header binary message payload to pack into an AIS Msg sls_header. 50 51 Fields in params: 52 - dac(uint): Designated Area Code 366 for US 53 - fid(uint): Functional Id (field automatically set to "1") 54 - reserved(uint): say what? (field automatically set to "0") 55 - MessageID(uint): Binary message indentifier 56 - BinaryData(binary): FIX: make this consume the rest! 57 @param params: Dictionary of field names/values. Throws a ValueError exception if required is missing 58 @param validate: Set to true to cause checking to occur. Runs slower. FIX: not implemented. 59 @rtype: BitVector 60 @return: encoded binary message (for binary messages, this needs to be wrapped in a msg 8 61 @note: The returned bits may not be 6 bit aligned. It is up to you to pad out the bits. 62 ''' 63 64 bvList = [] 65 bvList.append(binary.setBitVectorSize(BitVector(intVal=params['dac']),10)) 66 bvList.append(binary.setBitVectorSize(BitVector(intVal=1),6)) 67 bvList.append(binary.setBitVectorSize(BitVector(intVal=0),2)) 68 bvList.append(binary.setBitVectorSize(BitVector(intVal=params['MessageID']),6)) 69 bvList.append(params['BinaryData']) 70 71 return binary.joinBV(bvList)
72
73 -def decode(bv, validate=False):
74 '''Unpack a sls_header message 75 76 Fields in params: 77 - dac(uint): Designated Area Code 366 for US 78 - fid(uint): Functional Id (field automatically set to "1") 79 - reserved(uint): say what? (field automatically set to "0") 80 - MessageID(uint): Binary message indentifier 81 - BinaryData(binary): FIX: make this consume the rest! 82 @type bv: BitVector 83 @param bv: Bits defining a message 84 @param validate: Set to true to cause checking to occur. Runs slower. FIX: not implemented. 85 @rtype: dict 86 @return: params 87 ''' 88 89 #Would be nice to check the bit count here.. 90 #if validate: 91 # assert (len(bv)==FIX: SOME NUMBER) 92 r = {} 93 r['dac']=int(bv[0:10]) 94 r['fid']=1 95 r['reserved']=0 96 r['MessageID']=int(bv[18:24]) 97 r['BinaryData']=bv[24:] 98 return r
99
100 -def decodedac(bv, validate=False):
101 return int(bv[0:10])
102
103 -def decodefid(bv, validate=False):
104 return 1
105
106 -def decodereserved(bv, validate=False):
107 return 0
108
109 -def decodeMessageID(bv, validate=False):
110 return int(bv[18:24])
111
112 -def decodeBinaryData(bv, validate=False):
113 return bv[24:]
114
115 -def printFields(params, out=sys.stdout, format='std'):
116 '''Print a sls_header message to stdout. 117 118 Fields in params: 119 - dac(uint): Designated Area Code 366 for US 120 - fid(uint): Functional Id (field automatically set to "1") 121 - reserved(uint): say what? (field automatically set to "0") 122 - MessageID(uint): Binary message indentifier 123 - BinaryData(binary): FIX: make this consume the rest! 124 @param params: Dictionary of field names/values. 125 @param out: File like object to write to 126 @rtype: stdout 127 @return: text to out 128 ''' 129 130 if 'std'==format: 131 out.write("sls_header:\n") 132 if 'dac' in params: out.write(" dac: "+str(params['dac'])+"\n") 133 if 'fid' in params: out.write(" fid: "+str(params['fid'])+"\n") 134 if 'reserved' in params: out.write(" reserved: "+str(params['reserved'])+"\n") 135 if 'MessageID' in params: out.write(" MessageID: "+str(params['MessageID'])+"\n") 136 if 'BinaryData' in params: out.write(" BinaryData: "+str(params['BinaryData'])+"\n") 137 138 return # Nothing to return
139 140 141 142 ###################################################################### 143 # UNIT TESTING 144 ###################################################################### 145 import unittest
146 -def testParams():
147 '''Return a params file base on the testvalue tags. 148 @rtype: dict 149 @return: params based on testvalue tags 150 ''' 151 params = {} 152 params['dac'] = 366 153 params['fid'] = 1 154 params['reserved'] = 0 155 params['MessageID'] = 3 156 params['BinaryData'] = BitVector(bitstring='0') 157 158 return params
159
160 -class Testsls_header(unittest.TestCase):
161 '''Use testvalue tag text from each type to build test case the sls_header message'''
162 - def testEncodeDecode(self):
163 164 params = testParams() 165 bits = encode(params) 166 r = decode(bits) 167 168 # Check that each parameter came through ok. 169 self.failUnlessEqual(r['dac'],params['dac']) 170 self.failUnlessEqual(r['fid'],params['fid']) 171 self.failUnlessEqual(r['reserved'],params['reserved']) 172 self.failUnlessEqual(r['MessageID'],params['MessageID']) 173 self.failUnlessEqual(r['BinaryData'],params['BinaryData'])
174
175 -def addMsgOptions(parser):
176 parser.add_option('-d','--decode',dest='doDecode',default=False,action='store_true', 177 help='decode a "sls_header" AIS message') 178 parser.add_option('-e','--encode',dest='doEncode',default=False,action='store_true', 179 help='encode a "sls_header" AIS message') 180 parser.add_option('--dac-field', dest='dacField',metavar='uint',type='int' 181 ,help='Field parameter value [default: %default]') 182 parser.add_option('--MessageID-field', dest='MessageIDField',metavar='uint',type='int' 183 ,help='Field parameter value [default: %default]') 184 parser.add_option('--BinaryData-field', dest='BinaryDataField',metavar='binary',type='string' 185 ,help='Field parameter value [default: %default]')
186 187 ############################################################ 188 if __name__=='__main__': 189 190 from optparse import OptionParser 191 parser = OptionParser(usage="%prog [options]", 192 version="%prog "+__version__) 193 194 parser.add_option('--doc-test',dest='doctest',default=False,action='store_true', 195 help='run the documentation tests') 196 parser.add_option('--unit-test',dest='unittest',default=False,action='store_true', 197 help='run the unit tests') 198 parser.add_option('-v','--verbose',dest='verbose',default=False,action='store_true', 199 help='Make the test output verbose') 200 201 # FIX: remove nmea from binary messages. No way to build the whole packet? 202 # FIX: or build the surrounding msg 8 for a broadcast? 203 typeChoices = ('binary','nmeapayload','nmea') # FIX: what about a USCG type message? 204 parser.add_option('-t','--type',choices=typeChoices,type='choice',dest='ioType' 205 ,default='nmeapayload' 206 ,help='What kind of string to expect ('+', '.join(typeChoices)+') [default: %default]') 207 addMsgOptions(parser) 208 209 (options,args) = parser.parse_args() 210 success=True 211 212 if options.doctest: 213 import os; print os.path.basename(sys.argv[0]), 'doctests ...', 214 sys.argv= [sys.argv[0]] 215 if options.verbose: sys.argv.append('-v') 216 import doctest 217 numfail,numtests=doctest.testmod() 218 if numfail==0: print 'ok' 219 else: 220 print 'FAILED' 221 success=False 222 223 if not success: sys.exit('Something Failed') 224 del success # Hide success from epydoc 225 226 if options.unittest: 227 sys.argv = [sys.argv[0]] 228 if options.verbose: sys.argv.append('-v') 229 unittest.main() 230 231 if options.doEncode: 232 # First make sure all non required options are specified 233 if None==options.dacField: parser.error("missing value for dacField") 234 if None==options.MessageIDField: parser.error("missing value for MessageIDField") 235 if None==options.BinaryDataField: parser.error("missing value for BinaryDataField") 236 msgDict={ 237 'dac': options.dacField, 238 'fid': '1', 239 'reserved': '0', 240 'MessageID': options.MessageIDField, 241 'BinaryData': options.BinaryDataField, 242 } 243 244 bits = encode(msgDict) 245 if 'binary'==options.ioType: print str(bits) 246 elif 'nmeapayload'==options.ioType: 247 # FIX: figure out if this might be necessary at compile time 248 print "bitLen",len(bits) 249 bitLen=len(bits) 250 if bitLen%6!=0: 251 bits = bits + BitVector(size=(6 - (bitLen%6))) # Pad out to multiple of 6 252 print "result:",binary.bitvectoais6(bits)[0] 253 254 255 # FIX: Do not emit this option for the binary message payloads. Does not make sense. 256 elif 'nmea'==options.ioType: sys.exit("FIX: need to implement this capability") 257 else: sys.exit('ERROR: unknown ioType. Help!') 258 259 if options.doDecode: 260 for msg in args: 261 if 'binary'==options.ioType: 262 bv = BitVector(bitstring=msg) 263 printFields(decode(bv)) 264 265 elif 'nmeapayload'==options.ioType: 266 bv = binary.ais6tobitvec(msg) 267 printFields(decode(bv)) 268 269 elif 'nmea'==options.ioType: 270 bv = binary.ais6tobitvec(msg.split(',')[5]) 271 printFields(decode(bv)) 272 else: sys.exit('ERROR: unknown ioType. Help!') 273