try: import uctypes except ImportError: print("SKIP") raise SystemExit desc = { # arr is array at offset 0, of UINT8 elements, array size is 2 "arr": (uctypes.ARRAY | 0, uctypes.UINT8 | 2), # arr2 is array at offset 0, size 2, of structures defined recursively "arr2": (uctypes.ARRAY | 0, 2, {"b": uctypes.UINT8 | 0}), "arr3": (uctypes.ARRAY | 2, uctypes.UINT16 | 2), # aligned "arr5": (uctypes.ARRAY | 0, uctypes.UINT32 | 1), # unaligned "arr6": (uctypes.ARRAY | 1, uctypes.UINT32 | 1), "arr7": (uctypes.ARRAY | 0, 1, {"l": uctypes.UINT32 | 0}), "arr8": (uctypes.ARRAY | 1, 1, {"l": uctypes.UINT32 | 0}), } data = bytearray(5) S = uctypes.struct(uctypes.addressof(data), desc, uctypes.LITTLE_ENDIAN) # assign byte S.arr[0] = 0x11 print(hex(S.arr[0])) assert hex(S.arr[0]) == "0x11" # assign word S.arr3[0] = 0x2233 print(hex(S.arr3[0])) assert hex(S.arr3[0]) == "0x2233" # assign word, with index S.arr3[1] = 0x4455 print(hex(S.arr3[1])) assert hex(S.arr3[1]) == "0x4455" # assign long, aligned S.arr5[0] = 0x66778899 print(hex(S.arr5[0])) assert hex(S.arr5[0]) == "0x66778899" print(S.arr5[0] == S.arr7[0].l) assert S.arr5[0] == S.arr7[0].l # assign long, unaligned S.arr6[0] = 0xAABBCCDD print(hex(S.arr6[0])) assert hex(S.arr6[0]) == "0xaabbccdd" print(S.arr6[0] == S.arr8[0].l) assert S.arr6[0] == S.arr8[0].l