perf: skip BigInt in blake3 b2Compress counter conversion - #84
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blake3.b2Compress was calling fromBig(BigInt(counter), true) on every call to split the chunk counter into a (h, l) 32-bit pair. The counter is always a small safe integer — creating a BigInt and running BigInt bitwise ops just to split it burned allocations on every hash step. Inline the split directly: h = counter >>> 0 l = Math.floor(counter / 4294967296) >>> 0 Output is bit-identical to fromBig(..., true). Measured on autoresearch-scan (2000 charts, 8 workers, 2-run avg): previous (S2): 2.67 ms mean (3 runs: 2.634, 2.667, 2.717) this (S5): 2.59 ms mean (2 runs: 2.620, 2.556) delta: ~−3 to −6% mean 0 hash mismatches, 442/442 tests green. Patch extends @noble+hashes+1.8.0.patch with the blake3.js diff.
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blake3.b2Compress was calling fromBig(BigInt(counter), true) on every
call to split the chunk counter into a (h, l) 32-bit pair. The counter
is always a small safe integer — creating a BigInt and running BigInt
bitwise ops just to split it burned allocations on every hash step.
Inline the split directly:
h = counter >>> 0
l = Math.floor(counter / 4294967296) >>> 0
Output is bit-identical to fromBig(..., true).
Measured on autoresearch-scan (2000 charts, 8 workers, 2-run avg):
previous (S2): 2.67 ms mean (3 runs: 2.634, 2.667, 2.717)
this (S5): 2.59 ms mean (2 runs: 2.620, 2.556)
delta: ~−3 to −6% mean
0 hash mismatches, 442/442 tests green. Patch extends
@noble+hashes+1.8.0.patch with the blake3.js diff.