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• File src/target/trx_toolkit/data_msg.py:

  • Patch Set #2, Line 336: burst = memoryview(burst)[:EDGE_BURST_LEN]

    I never used memoryview nor read about the details, but in line "burst = memoryview(burst)[:EDGE_BUR […]

    ah, now I see. So memoryview(burst) creates only a view of original burst object data. This is basically a small object that points to another base object to know where to get the data without copying them. Then slice operation of memoryview returns another memoryview without copying the data - that adjusted memoryview refers to base object, but knows to view not the whole data of it, but only some range. It is still a small object that does not copy base's data.

    ```
    In [7]: burst = bytearray(range(10))                                                                                                    
                                                                                                                                             
    In [8]: burst                                                                                                                           
    Out[8]: bytearray(b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t')                                                                            
                                                                                                                                             
    In [9]: burst *= 100

    In [10]: burst
    Out[10]: bytearray(b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t...\x00\x01\x02\x03\x04\x05\x06\x07\x08\t')

    In [11]: len(burst)
    Out[11]: 1000

    In [12]: sys.getsizeof(burst)
    Out[12]: 1057

    In [13]: m = memoryview(burst)

    In [14]: len(m)
    Out[14]: 1000

    In [15]: sys.getsizeof(m)
    Out[15]: 184

    In [16]: m[0]
    Out[16]: 0

    In [17]: burst[0]
    Out[17]: 0

    In [18]: burst[1]
    Out[18]: 1

    In [19]: m[1]
    Out[19]: 1

    In [20]: m[2]
    Out[20]: 2

    In [21]: burst[2]
    Out[21]: 2

    In [22]: mm = m[2:]

    In [23]: len(mm)
    Out[23]: 998

    In [24]: sys.getsizeof(mm)
    Out[24]: 184

    In [25]: mm[0]
    Out[25]: 2

    In [26]: m[2]
    Out[26]: 2

    In [27]: mm[1]
    Out[27]: 3

    In [28]: m[3]
    Out[28]: 3

    In [29]: burst[3]
    Out[29]: 3
    ```

    
    Please see https://docs.python.org/3/library/stdtypes.html#memoryview for details.

    P.S. Unfortunately constant-size of memoryview structure turned out to be not so small, so it still contributes to overhead for not so small bursts. https://github.com/python/cpython/blob/v3.11.9-9-g1b0e63c81b5/Include/memoryobject.h#L57-L66

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