Hojun-Cho
aadc6618f0
Every // ---- section banner dies (132 -> 0): names carry the WHAT. Narration deleted (filename restatements, run-with lines, what-the- next-line-does); every ref/hare cite, task cite, divergence, ABI/ layout contract, and ownership qualifier kept (borrowed-view lines restored where the sweep over-cut). Comment-only proven: all 442 walk-workdir .s and 32 import-probe .s byte-identical before/after; libbyteid 56-roster all-ID.
35 lines
1.0 KiB
Plaintext
35 lines
1.0 KiB
Plaintext
// Same shape as lib/hash/crc16: per-byte inline polynomial shift,
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// no precomputed table. Slower than Hare's table-driven path by ~8x
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// per byte but produces identical answers.
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package crc32;
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def IEEE: u32 = 0xEDB88320u32; // gzip, PNG, zip, Ethernet
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def CASTAGNOLI: u32 = 0x82F63B78u32; // iSCSI, SCTP, SSE4.2
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def KOOPMAN: u32 = 0xEB31D82Eu32; // small datasets
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// sum32 — fold `buf` under `poly` (reversed form). Initial cval is ~0u32.
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export fn sum32(buf: []u8, poly: u32) u32 = {
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let c: u32 = 0xFFFFFFFFu32;
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let i: i32 = 0;
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for (i < buf.len) {
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let t: u32 = (c & 0xFFu32) ^ (buf[i]: u32);
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let z: i32 = 0;
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for (z < 8) {
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if ((t & 1u32) == 1u32) {
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t = (t >> 1u32) ^ poly;
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} else {
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t = t >> 1u32;
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};
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z += 1;
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};
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c = t ^ (c >> 8u32);
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i += 1;
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};
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return ~c;
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};
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export fn sum32ieee(buf: []u8) u32 = { return sum32(buf, IEEE); };
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export fn sum32castagnoli(buf: []u8) u32 = { return sum32(buf, CASTAGNOLI); };
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export fn sum32koopman(buf: []u8) u32 = { return sum32(buf, KOOPMAN); };
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