Merge pull request aeron-io#279 from tfgm-bud/master

[python] Add python example

Author: tmontgomery

README.md

@@ -125,6 +125,12 @@ Then build and test with CMake __in the build subdirectory created by the gradle
 C# Build
 --------
 
-See [readme.md](https://github.com/real-logic/simple-binary-encoding/tree/master/vs2013) in vs2013 directory
+See [README.md](https://github.com/real-logic/simple-binary-encoding/tree/master/vs2013) in vs2013 directory
+
+
+Python Support
+--------------
+
+See [README.md](https://github.com/real-logic/simple-binary-encoding/tree/master/examples/python) in python directory.
 
 

examples/python/.gitignore

@@ -0,0 +1,2 @@
+baseline/*
+car.bin

examples/python/README.md

@@ -0,0 +1,22 @@
+Simple test programs demonstrating encoding and decoding with python
+
+based on work originally by Mark McIlroy (https://github.com/mmcilroy/sbe_tests)
+
+First build SBE as usual \(see [README.md](https://github.com/real-logic/simple-binary-encoding)\)
+```
+# SBE Jar file will be in simple-binary-encoding/build/libs
+#
+SBE_JAR=some/path/to/sbe.jar
+SCHEMA_XML=../resources/example-schema.xml
+
+# generate python code
+java -Dsbe.target.language=python -jar ${SBE_JAR} ${SCHEMA_XML}
+echo "" > baseline/__init__.py
+
+# encode car using python
+python encode_example.py
+
+# decode car using python
+python decode_example.py
+
+```

examples/python/decode_example.py

@@ -0,0 +1,60 @@
+import io
+from baseline.Car import Car
+
+length = 129
+inp = io.open('car.bin', 'rb')
+buffer = inp.read(length)
+
+# start decoding
+car = Car()
+car.wrapForDecode(buffer, 0, car.sbeBlockLength(), car.sbeSchemaVersion(), length)
+
+# single fixed fields
+print('serialNumber: '+str(car.getSerialNumber()))
+print('modelYear: '+str(car.getModelYear()))
+print('available: '+str(car.getAvailable()))
+print('code: '+str(car.getCode()))
+
+# fixed arrays
+for i in range(0,car.someNumbersLength()):
+ print('someNumber'+str(i)+': '+str(car.getSomeNumbers(i)))
+
+for i in range(0,car.vehicleCodeLength()):
+ print('vehicleCode'+str(i)+': '+str(car.getVehicleCode(i)))
+
+# bitsets
+print('cruiseControl: '+str(car.extras().getCruiseControl()))
+print('sportsPack: '+str(car.extras().getSportsPack()))
+print('sunRoof: '+str(car.extras().getSunRoof()))
+
+# composites
+print('capacity: '+str(car.engine().getCapacity()))
+print('numCylinders: '+str(car.engine().getNumCylinders()))
+print('maxRpm: '+str(car.engine().maxRpm()))
+
+for i in range(0,car.engine().manufacturerCodeLength()):
+ print('manufacturerCode'+str(i)+': '+str(car.engine().getManufacturerCode(i)))
+
+# groups
+figures = car.fuelFigures()
+while figures.hasNext():
+ figures.next()
+ print('speed: '+str(figures.getSpeed()))
+ print('mpg: '+str(figures.getMpg()))
+
+figures = car.performanceFigures()
+while figures.hasNext():
+ figures.next()
+ print('octaneRating: '+str(figures.getOctaneRating()))
+ acceleration = figures.acceleration()
+ while acceleration.hasNext():
+ acceleration.next()
+ print('mph: '+str(acceleration.getMph()))
+ print('seconds: '+str(acceleration.getSeconds()))
+
+# variable length
+make = car.getMake()
+print('make: '+str(make))
+
+model = car.getModel()
+print('model: '+str(model))

examples/python/encode_example.py

@@ -0,0 +1,73 @@
+import io
+from baseline.Car import Car
+from baseline.BooleanType import BooleanType
+from baseline.Model import Model
+
+buffer = bytearray(2048)
+
+# start decoding
+car = Car()
+car.wrapForEncode(buffer, 0, len(buffer))
+
+car.setSerialNumber(1234)
+car.setModelYear(2013)
+car.setAvailable(BooleanType.TRUE)
+car.setCode(Model.A)
+
+# fixed arrays
+for i in range(0, car.someNumbersLength()) :
+ car.setSomeNumbers(i, i)
+
+
+code = [x for x in 'abcdef']
+for i in range(0, car.vehicleCodeLength()):
+ car.setVehicleCode(i, code[i])
+
+car.extras().setCruiseControl(True)
+car.extras().setSportsPack(True)
+car.extras().setSunRoof(False)
+
+# composites
+car.engine().setCapacity(2000)
+car.engine().setNumCylinders(4)
+code = [x for x in '123']
+for i in range(0, car.engine().manufacturerCodeLength()):
+ car.engine().setManufacturerCode(i, code[i])
+
+# groups
+fuelFigures = car.fuelFiguresCount(3)
+for speed, mpg in [(30,35.9), (55,49.0), (75,40.0)]:
+ fuelFigures.next()
+ fuelFigures.setSpeed(speed)
+ fuelFigures.setMpg(mpg)
+
+
+performanceFigures = car.performanceFiguresCount(2)
+
+performanceFigures.next()
+performanceFigures.setOctaneRating(95)
+
+acceleration = performanceFigures.accelerationCount(3)
+for mph, seconds in [(30,4.0), (60,7.5), (100,12.2)]:
+ acceleration.next()
+ acceleration.setMph(mph)
+ acceleration.setSeconds(seconds)
+
+performanceFigures.next()
+performanceFigures.setOctaneRating(99)
+
+acceleration = performanceFigures.accelerationCount(3)
+for mph, seconds in [(30,3.8), (60,7.1), (100,11.8)]:
+ acceleration.next()
+ acceleration.setMph(mph)
+ acceleration.setSeconds(seconds)
+
+# variable length
+car.setMake('Honda')
+car.setModel('Civic VTi')
+
+length = car.encodedLength()
+
+f = io.open('car.bin', 'wb')
+f.write(buffer[:length])
+f.close()