Support more than one nested struct.
Bug: 34812052
Test: new unit test passes
Change-Id: I7c3f4d73be01e5000e8b870e9178d6408993ae0d
diff --git a/net/test/cstruct.py b/net/test/cstruct.py
index 91cd72e..8fe916a 100644
--- a/net/test/cstruct.py
+++ b/net/test/cstruct.py
@@ -17,7 +17,8 @@
Example usage:
>>> # Declare a struct type by specifying name, field formats and field names.
-... # Field formats are the same as those used in the struct module.
+... # Field formats are the same as those used in the struct module, except:
+... # - S: Nested Struct.
... import cstruct
>>> NLMsgHdr = cstruct.Struct("NLMsgHdr", "=LHHLL", "length type flags seq pid")
>>>
@@ -44,6 +45,15 @@
>>> cstruct.Read(data, NLMsgHdr)
(NLMsgHdr(length=44, type=33, flags=2, seq=0, pid=510), 'more data')
>>>
+>>> # Structs can contain one or more nested structs. The nested struct types
+... # are specified in a list as an optional last argument. Nested structs may
+... # contain nested structs.
+... S = cstruct.Struct("S", "=BI", "byte1 int2")
+>>> N = cstruct.Struct("N", "!BSiS", "byte1 s2 int3 s2", [S, S])
+>>> NN = cstruct.Struct("NN", "SHS", "s1 word2 n3", [S, N])
+>>> nn = NN((S((1, 25000)), -29876, N((55, S((5, 6)), 1111, S((7, 8))))))
+>>> nn.n3.s2.int2 = 5
+>>>
"""
import ctypes
@@ -52,9 +62,12 @@
def CalcNumElements(fmt):
+ prevlen = len(fmt)
+ fmt = fmt.replace("S", "")
+ numstructs = prevlen - len(fmt)
size = struct.calcsize(fmt)
elements = struct.unpack(fmt, "\x00" * size)
- return len(elements)
+ return len(elements) + numstructs
def Struct(name, fmt, fieldnames, substructs={}):
diff --git a/net/test/cstruct_test.py b/net/test/cstruct_test.py
index 2d5a408..70ba90c 100755
--- a/net/test/cstruct_test.py
+++ b/net/test/cstruct_test.py
@@ -55,6 +55,45 @@
self.CheckEquals(i, i)
self.CheckEquals(a1, a3)
+ def testNestedStructs(self):
+ Nested = cstruct.Struct("Nested", "!HSSi",
+ "word1 nest2 nest3 int4",
+ [TestStructA, TestStructB])
+ DoubleNested = cstruct.Struct("DoubleNested", "SSB",
+ "nest1 nest2 byte3",
+ [TestStructA, Nested])
+ d = DoubleNested((TestStructA((1, 2)),
+ Nested((5, TestStructA((3, 4)), TestStructB((7, 8)), 9)),
+ 6))
+
+ expectedlen = (len(TestStructA) +
+ 2 + len(TestStructA) + len(TestStructB) + 4 +
+ 1)
+ self.assertEquals(expectedlen, len(DoubleNested))
+
+ self.assertEquals(7, d.nest2.nest3.byte1)
+
+ d.byte3 = 252
+ d.nest2.word1 = 33214
+ n = d.nest2
+ n.int4 = -55
+ t = n.nest3
+ t.int2 = 33627591
+
+ self.assertEquals(33627591, d.nest2.nest3.int2)
+
+ expected = (
+ "DoubleNested(nest1=TestStructA(byte1=1, int2=2),"
+ " nest2=Nested(word1=33214, nest2=TestStructA(byte1=3, int2=4),"
+ " nest3=TestStructB(byte1=7, int2=33627591), int4=-55), byte3=252)")
+ self.assertEquals(expected, str(d))
+ expected = ("01" "02000000"
+ "81be" "03" "04000000"
+ "07" "c71d0102" "ffffffc9" "fc").decode("hex")
+ self.assertEquals(expected, d.Pack())
+ unpacked = DoubleNested(expected)
+ self.CheckEquals(unpacked, d)
+
if __name__ == "__main__":
unittest.main()
