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: 2007-01-04 $'.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 elif 'html'==format: 138 out.write("<h3>BinaryData<h3>\n") 139 out.write("<table border=\"1\">\n") 140 out.write("<tr bgcolor=\"orange\">\n") 141 out.write("<th align=\"left\">Field Name</th>\n") 142 out.write("<th align=\"left\">Type</th>\n") 143 out.write("<th align=\"left\">Value</th>\n") 144 out.write("<th align=\"left\">Value in Lookup Table</th>\n") 145 out.write("\n") 146 out.write("<tr>\n") 147 out.write("<td>dac</td>\n") 148 out.write("<td>uint</td>\n") 149 if 'dac' in params: 150 out.write(" <td>"+str(params['dac'])+"</td>\n") 151 out.write(" <td>"+str(params['dac'])+"</td>\n") 152 out.write("</tr>\n") 153 out.write("\n") 154 out.write("<tr>\n") 155 out.write("<td>fid</td>\n") 156 out.write("<td>uint</td>\n") 157 if 'fid' in params: 158 out.write(" <td>"+str(params['fid'])+"</td>\n") 159 out.write(" <td>"+str(params['fid'])+"</td>\n") 160 out.write("</tr>\n") 161 out.write("\n") 162 out.write("<tr>\n") 163 out.write("<td>reserved</td>\n") 164 out.write("<td>uint</td>\n") 165 if 'reserved' in params: 166 out.write(" <td>"+str(params['reserved'])+"</td>\n") 167 out.write(" <td>"+str(params['reserved'])+"</td>\n") 168 out.write("</tr>\n") 169 out.write("\n") 170 out.write("<tr>\n") 171 out.write("<td>MessageID</td>\n") 172 out.write("<td>uint</td>\n") 173 if 'MessageID' in params: 174 out.write(" <td>"+str(params['MessageID'])+"</td>\n") 175 out.write(" <td>"+str(params['MessageID'])+"</td>\n") 176 out.write("</tr>\n") 177 out.write("\n") 178 out.write("<tr>\n") 179 out.write("<td>BinaryData</td>\n") 180 out.write("<td>binary</td>\n") 181 if 'BinaryData' in params: 182 out.write(" <td>"+str(params['BinaryData'])+"</td>\n") 183 out.write(" <td>"+str(params['BinaryData'])+"</td>\n") 184 out.write("</tr>\n") 185 out.write("</table>\n") 186 else: 187 print "ERROR: unknown format:",format 188 assert False 189 190 return # Nothing to return
191 192 193 194 ###################################################################### 195 # UNIT TESTING 196 ###################################################################### 197 import unittest
198 -def testParams():
199 '''Return a params file base on the testvalue tags. 200 @rtype: dict 201 @return: params based on testvalue tags 202 ''' 203 params = {} 204 params['dac'] = 366 205 params['fid'] = 1 206 params['reserved'] = 0 207 params['MessageID'] = 3 208 params['BinaryData'] = BitVector(bitstring='0') 209 210 return params
211
212 -class Testsls_header(unittest.TestCase):
213 '''Use testvalue tag text from each type to build test case the sls_header message'''
214 - def testEncodeDecode(self):
215 216 params = testParams() 217 bits = encode(params) 218 r = decode(bits) 219 220 # Check that each parameter came through ok. 221 self.failUnlessEqual(r['dac'],params['dac']) 222 self.failUnlessEqual(r['fid'],params['fid']) 223 self.failUnlessEqual(r['reserved'],params['reserved']) 224 self.failUnlessEqual(r['MessageID'],params['MessageID']) 225 self.failUnlessEqual(r['BinaryData'],params['BinaryData'])
226
227 -def addMsgOptions(parser):
228 parser.add_option('-d','--decode',dest='doDecode',default=False,action='store_true', 229 help='decode a "sls_header" AIS message') 230 parser.add_option('-e','--encode',dest='doEncode',default=False,action='store_true', 231 help='encode a "sls_header" AIS message') 232 parser.add_option('--dac-field', dest='dacField',metavar='uint',type='int' 233 ,help='Field parameter value [default: %default]') 234 parser.add_option('--MessageID-field', dest='MessageIDField',metavar='uint',type='int' 235 ,help='Field parameter value [default: %default]') 236 parser.add_option('--BinaryData-field', dest='BinaryDataField',metavar='binary',type='string' 237 ,help='Field parameter value [default: %default]')
238 239 ############################################################ 240 if __name__=='__main__': 241 242 from optparse import OptionParser 243 parser = OptionParser(usage="%prog [options]", 244 version="%prog "+__version__) 245 246 parser.add_option('--doc-test',dest='doctest',default=False,action='store_true', 247 help='run the documentation tests') 248 parser.add_option('--unit-test',dest='unittest',default=False,action='store_true', 249 help='run the unit tests') 250 parser.add_option('-v','--verbose',dest='verbose',default=False,action='store_true', 251 help='Make the test output verbose') 252 253 # FIX: remove nmea from binary messages. No way to build the whole packet? 254 # FIX: or build the surrounding msg 8 for a broadcast? 255 typeChoices = ('binary','nmeapayload','nmea') # FIX: what about a USCG type message? 256 parser.add_option('-t','--type',choices=typeChoices,type='choice',dest='ioType' 257 ,default='nmeapayload' 258 ,help='What kind of string to expect ('+', '.join(typeChoices)+') [default: %default]') 259 260 outputChoices = ('std','html','xml') 261 parser.add_option('-T','--output-type',choices=outputChoices,type='choice',dest='outputType' 262 ,default='std' 263 ,help='What kind of string to output ('+', '.join(outputChoices)+') [default: %default]') 264 265 parser.add_option('-o','--output',dest='outputFileName',default=None, 266 help='Name of the python file to write [default: stdout]') 267 268 addMsgOptions(parser) 269 270 (options,args) = parser.parse_args() 271 success=True 272 273 if options.doctest: 274 import os; print os.path.basename(sys.argv[0]), 'doctests ...', 275 sys.argv= [sys.argv[0]] 276 if options.verbose: sys.argv.append('-v') 277 import doctest 278 numfail,numtests=doctest.testmod() 279 if numfail==0: print 'ok' 280 else: 281 print 'FAILED' 282 success=False 283 284 if not success: sys.exit('Something Failed') 285 del success # Hide success from epydoc 286 287 if options.unittest: 288 sys.argv = [sys.argv[0]] 289 if options.verbose: sys.argv.append('-v') 290 unittest.main() 291 292 outfile = sys.stdout 293 if None!=options.outputFileName: 294 outfile = file(options.outputFileName,'w') 295 296 297 if options.doEncode: 298 # First make sure all non required options are specified 299 if None==options.dacField: parser.error("missing value for dacField") 300 if None==options.MessageIDField: parser.error("missing value for MessageIDField") 301 if None==options.BinaryDataField: parser.error("missing value for BinaryDataField") 302 msgDict={ 303 'dac': options.dacField, 304 'fid': '1', 305 'reserved': '0', 306 'MessageID': options.MessageIDField, 307 'BinaryData': options.BinaryDataField, 308 } 309 310 bits = encode(msgDict) 311 if 'binary'==options.ioType: print str(bits) 312 elif 'nmeapayload'==options.ioType: 313 # FIX: figure out if this might be necessary at compile time 314 print "bitLen",len(bits) 315 bitLen=len(bits) 316 if bitLen%6!=0: 317 bits = bits + BitVector(size=(6 - (bitLen%6))) # Pad out to multiple of 6 318 print "result:",binary.bitvectoais6(bits)[0] 319 320 321 # FIX: Do not emit this option for the binary message payloads. Does not make sense. 322 elif 'nmea'==options.ioType: sys.exit("FIX: need to implement this capability") 323 else: sys.exit('ERROR: unknown ioType. Help!') 324 325 if options.doDecode: 326 for msg in args: 327 bv = None 328 if 'binary' == options.ioType: bv = BitVector(bitstring=msg) 329 elif 'nmeapayload'== options.ioType: bv = binary.ais6tobitvec(msg) 330 elif 'nmea' == options.ioType: bv = binary.ais6tobitvec(msg.split(',')[5]) 331 else: sys.exit('ERROR: unknown ioType. Help!') 332 333 printFields(decode(bv),out=outfile,format=options.outputType) 334