My code is pre-aligning the needle to a byte boundary,

That would, for my purposes, mean that the entire needle would need to be copied, and the time taken counted.

The reason is hinted at in the 6 argument function signature(*) I posted in the OP:

U64 bsSearch( U64 *hay, U8 oHay, U64 lHay, U64 *ndl, U8 oNdl, U64 lNdl
+ );

[download]

Both the haystack and needle will be subsections of -- potentially much larger -- bitstrings; and shifting them in-place is not on, because they are effectively just windows into the parent bitstrings -- think substr refs. (Though I guess you might be able to rotate them in place -- rotate so that no bits are lost -- then rotate them back afterwards; but again, the time taken would have to be counted.).

That's why I'm now recoding in OO-style; so that the function signature can become: bvSearch( BV *hay, BV *ndl ); and I can hide the nasty offsets, cross-boundary manipulations and (in particular) end-of-bitstring sub-64-bit bits behind the curtains.

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In reply to Re^18: [OT] The interesting problem of comparing (long) bit-strings. by BrowserUk
in thread [OT] The interesting problem of comparing bit-strings. by BrowserUk

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