[#40] Add fromReader method to runtime arrays

ndsev · Nov 22, 2018 · 23073c7 · 23073c7
1 parent 6bdb1d5
commit 23073c7
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Showing 2 changed files with 32 additions and 0 deletions.
diff --git a/compiler/extensions/python/runtime/src/zserio/array.py b/compiler/extensions/python/runtime/src/zserio/array.py
@@ -38,6 +38,29 @@ def __init__(self, arrayTraits, rawArray=None, *, isAuto=None, isImplicit=None,
         self._setOffsetMethod = setOffsetMethod
         self._checkOffsetMethod = checkOffsetMethod
 
+    @classmethod
+    def fromReader(cls, arrayTraits, reader, size=None, *, isAuto=None, isImplicit=None, setOffsetMethod=None,
+                   checkOffsetMethod=None):
+        """
+        Constructs array and reads elements from the given bit stream reader.
+
+        :param arrayTraits: Array traits which specify the array type.
+        :param reader: Bit stream from which to read.
+        :param size: Number of elements to read or None in case of implicit or auto arrays.
+        :param rawArray: Native python list which will be hold by this abstraction.
+        :param isAuto: True if mapped Zserio array is auto array.
+        :param isImplicit: True if mapped Zserio array is implicit array.
+        :param setOffsetMethod:  Set offset method if mapped Zserio array is indexed offset array.
+        :param checkOffsetMethod: Check offset method if mapped Zserio array is indexed offset array.
+        :returns: Array instance filled using given bit stream reader.
+        """
+
+        instance = cls(arrayTraits, isAuto=isAuto, isImplicit=isImplicit, setOffsetMethod=setOffsetMethod,
+                       checkOffsetMethod=checkOffsetMethod)
+        instance.read(reader, size)
+
+        return instance
+
     def __eq__(self, other):
         return (self._rawArray == other._rawArray and
                 self._arrayTraits == other._arrayTraits and

diff --git a/compiler/extensions/python/runtime/tests/test_array.py b/compiler/extensions/python/runtime/tests/test_array.py
@@ -167,6 +167,7 @@ def write(self, writer):
         self._testArray(arrayTraits, array1Values, array1BitSizeOf, array1AligneBitSizeOf, array2Values)
 
     def _testArray(self, arrayTraits, array1Values, array1BitSizeOf, array1AlignedBitSizeOf, array2Values):
+        self._testFromReader(arrayTraits, array1Values)
         self._testHashCode(arrayTraits, array1Values, array2Values)
         self._testLen(arrayTraits, array1Values)
         self._testGetItem(arrayTraits, array1Values)
@@ -178,6 +179,14 @@ def _testArray(self, arrayTraits, array1Values, array1BitSizeOf, array1AlignedBi
         self._testRead(arrayTraits, array1Values)
         self._testWrite(arrayTraits, array1Values, array1BitSizeOf, array1AlignedBitSizeOf)
 
+    def _testFromReader(self, arrayTraits, arrayValues):
+        array = Array(arrayTraits, arrayValues)
+        writer = BitStreamWriter()
+        array.write(writer)
+        reader = BitStreamReader(writer.getByteArray())
+        readArray = Array.fromReader(arrayTraits, reader, len(arrayValues))
+        self.assertEqual(array, readArray)
+
     def _testHashCode(self, arrayTraits, array1Values, array2Values):
         array1 = Array(arrayTraits, array1Values)
         array2 = Array(arrayTraits, array2Values)