Bit Packing Decode

Problem

Unpack count integers of the given bit width from a list of byte values, where bytes are laid out least-significant first and values are packed continuously without padding.

The first value occupies the lowest bits of the stream. Assume 1 <= bits <= 8 and that the byte list holds enough bits.

Hint

Build one big integer from the bytes, then shift and mask out each field.

Test cases

case 1

in: [[170],2,4]

expected: [2,2,2,2]

case 2

in: [[1,2],8,2]

expected: [1,2]

case 3

in: [[5],4,2]

expected: [5,0]

case 4

in: [[0,0],1,8]

expected: [0,0,0,0,0,0,0,0]

case 5

in: [[129,3],1,16]

expected: [1,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0]

Starter codePython

def bit_packing_decode(packed, bits, count):
    # Your code here
    pass

5 test cases · run your code against them in the editor