Optimize Integer <-> ByteString conversions #7439
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zliu41
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Dec 12, 2025
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zliu41
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This is quite low level stuff, but I've gone through the logic and it all checks out.
| LittleEndian -> pure () | ||
| BigEndian -> reverseBuffer ptr desiredLength | ||
| goSmallLE :: Ptr Word8 -> Int -> Int# -> IO () | ||
| goSmallLE ptr offset remaining# |
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Add a bang to offset? Ditto for all other Int arguments.
| copyByteArrayToAddr ptr (ByteArray ba#) 0 minLength | ||
| case requestedByteOrder of | ||
| LittleEndian -> pure () | ||
| BigEndian -> reverseBuffer ptr desiredLength |
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Any idea how much overhead reverseBuffer has?
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This optimizes the conversions between
IntegerandByteString, as we can now rely onIntegerinternals, which lets us use direct copying instead of digit-by-digit extraction and reconstruction.I did not changelog this, as this change is designed to be invisible at the API level. This will require these operations to be re-costed, as this change means we should see an algorithmic improvement (from$\Theta(n^2)$ to $\Theta(n)$ ).