TBitHelper has better masking algorithm #930
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I was going through the TBitReader and found this optimization for more compliant masks.
Technically, this shouldn't even be a problem in the code but I want to use the best mask calculation algorithm as an example for others. The problem was collision left shifting 1 by the total number of bits is that the shift would push the bit off.
Instead of
(1<<$bits) - 1it should be~(-1 << $bits)as this preserves the masking when $bits = PHP_INT_SIZE * 8