#!/usr/bin/python
#
# Copyright 2016 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import unittest
import cstruct
# These aren't constants, they're classes. So, pylint: disable=invalid-name
TestStructA = cstruct.Struct("TestStructA", "=BI", "byte1 int2")
TestStructB = cstruct.Struct("TestStructB", "=BI", "byte1 int2")
class CstructTest(unittest.TestCase):
def CheckEquals(self, a, b):
self.assertEquals(a, b)
self.assertEquals(b, a)
assert a == b
assert b == a
assert not (a != b) # pylint: disable=g-comparison-negation,superfluous-parens
assert not (b != a) # pylint: disable=g-comparison-negation,superfluous-parens
def CheckNotEquals(self, a, b):
self.assertNotEquals(a, b)
self.assertNotEquals(b, a)
assert a != b
assert b != a
assert not (a == b) # pylint: disable=g-comparison-negation,superfluous-parens
assert not (b == a) # pylint: disable=g-comparison-negation,superfluous-parens
def testEqAndNe(self):
a1 = TestStructA((1, 2))
a2 = TestStructA((2, 3))
a3 = TestStructA((1, 2))
b = TestStructB((1, 2))
self.CheckNotEquals(a1, b)
self.CheckNotEquals(a2, b)
self.CheckNotEquals(a1, a2)
self.CheckNotEquals(a2, a3)
for i in [a1, a2, a3, b]:
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)
def testNullTerminatedStrings(self):
TestStruct = cstruct.Struct("TestStruct", "B16si16AH",
"byte1 string2 int3 ascii4 word5")
nullstr = "hello" + (16 - len("hello")) * "\x00"
t = TestStruct((2, nullstr, 12345, nullstr, 33210))
expected = ("TestStruct(byte1=2, string2=68656c6c6f0000000000000000000000,"
" int3=12345, ascii4=hello, word5=33210)")
self.assertEquals(expected, str(t))
embeddednull = "hello\x00visible123"
t = TestStruct((2, embeddednull, 12345, embeddednull, 33210))
expected = ("TestStruct(byte1=2, string2=68656c6c6f0076697369626c65313233,"
" int3=12345, ascii4=hello\x00visible123, word5=33210)")
self.assertEquals(expected, str(t))
def testZeroInitialization(self):
TestStruct = cstruct.Struct("TestStruct", "B16si16AH",
"byte1 string2 int3 ascii4 word5")
t = TestStruct()
self.assertEquals(0, t.byte1)
self.assertEquals("\x00" * 16, t.string2)
self.assertEquals(0, t.int3)
self.assertEquals("\x00" * 16, t.ascii4)
self.assertEquals(0, t.word5)
self.assertEquals("\x00" * len(TestStruct), t.Pack())
def testKeywordInitialization(self):
TestStruct = cstruct.Struct("TestStruct", "=B16sIH",
"byte1 string2 int3 word4")
text = "hello world! ^_^"
text_bytes = text.encode("hex")
# Populate all fields
t1 = TestStruct(byte1=1, string2=text, int3=0xFEDCBA98, word4=0x1234)
expected = ("01" + text_bytes + "98BADCFE" "3412").decode("hex")
self.assertEquals(expected, t1.Pack())
# Partially populated
t1 = TestStruct(string2=text, word4=0x1234)
expected = ("00" + text_bytes + "00000000" "3412").decode("hex")
self.assertEquals(expected, t1.Pack())
def testCstructOffset(self):
TestStruct = cstruct.Struct("TestStruct", "B16si16AH",
"byte1 string2 int3 ascii4 word5")
nullstr = "hello" + (16 - len("hello")) * "\x00"
t = TestStruct((2, nullstr, 12345, nullstr, 33210))
self.assertEquals(0, t.offset("byte1"))
self.assertEquals(1, t.offset("string2")) # sizeof(byte)
self.assertEquals(17, t.offset("int3")) # sizeof(byte) + 16*sizeof(char)
# The integer is automatically padded by the struct module
# to match native alignment.
# offset = sizeof(byte) + 16*sizeof(char) + padding + sizeof(int)
self.assertEquals(24, t.offset("ascii4"))
self.assertEquals(40, t.offset("word5"))
self.assertRaises(KeyError, t.offset, "random")
# TODO: Add support for nested struct offset
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))
self.assertEqual(0, d.offset("nest1"))
self.assertEqual(len(TestStructA), d.offset("nest2"))
self.assertEqual(len(TestStructA) + len(Nested), d.offset("byte3"))
self.assertRaises(KeyError, t.offset, "word1")
def testDefinitionFieldMismatch(self):
cstruct.Struct("TestA", "=BI", "byte1 int2")
cstruct.Struct("TestA", "=BxxxxxIx", "byte1 int2")
with self.assertRaises(ValueError):
cstruct.Struct("TestA", "=B", "byte1 int2")
with self.assertRaises(ValueError):
cstruct.Struct("TestA", "=BI", "byte1")
Nested = cstruct.Struct("Nested", "!II", "int1 int2")
cstruct.Struct("TestB", "=BSI", "byte1 nest2 int3", [Nested])
cstruct.Struct("TestB", "=BxSxIx", "byte1 nest2 int3", [Nested])
with self.assertRaises(ValueError):
cstruct.Struct("TestB", "=BSI", "byte1 int3", [Nested])
with self.assertRaises(ValueError):
cstruct.Struct("TestB", "=BSI", "byte1 nest2", [Nested])
cstruct.Struct("TestC", "=BSSI", "byte1 nest2 nest3 int4", [Nested, Nested])
with self.assertRaises(ValueError):
cstruct.Struct("TestC", "=BSSI", "byte1 nest2 int4", [Nested, Nested])
if __name__ == "__main__":
unittest.main()