84 lines
No EOL
4.9 KiB
JavaScript
84 lines
No EOL
4.9 KiB
JavaScript
const U32_MASK64 = /* @__PURE__ */ BigInt(2 ** 32 - 1);
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const _32n = /* @__PURE__ */ BigInt(32);
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// Split bigint into two 32-bit halves. With `le=true`, returned fields become `{ h: low, l: high
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// }` to match little-endian word order rather than the property names.
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function fromBig(n, le = false) {
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if (le)
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return { h: Number(n & U32_MASK64), l: Number((n >> _32n) & U32_MASK64) };
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return { h: Number((n >> _32n) & U32_MASK64) | 0, l: Number(n & U32_MASK64) | 0 };
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}
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// Split bigint list into `[highWords, lowWords]` when `le=false`; with `le=true`, the first array
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// holds the low halves because `fromBig(...)` swaps the semantic meaning of `h` and `l`.
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function split(lst, le = false) {
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const len = lst.length;
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let Ah = new Uint32Array(len);
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let Al = new Uint32Array(len);
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for (let i = 0; i < len; i++) {
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const { h, l } = fromBig(lst[i], le);
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[Ah[i], Al[i]] = [h, l];
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}
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return [Ah, Al];
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}
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// Combine explicit `(high, low)` 32-bit halves into a bigint; `>>> 0` normalizes signed JS
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// bitwise results back to uint32 first, and little-endian callers must swap.
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const toBig = (h, l) => (BigInt(h >>> 0) << _32n) | BigInt(l >>> 0);
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// High 32-bit half of a 64-bit logical right shift for `s` in `0..31`.
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const shrSH = (h, _l, s) => h >>> s;
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// Low 32-bit half of a 64-bit logical right shift, valid for `s` in `1..31`.
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const shrSL = (h, l, s) => (h << (32 - s)) | (l >>> s);
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// High 32-bit half of a 64-bit right rotate, valid for `s` in `1..31`.
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const rotrSH = (h, l, s) => (h >>> s) | (l << (32 - s));
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// Low 32-bit half of a 64-bit right rotate, valid for `s` in `1..31`.
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const rotrSL = (h, l, s) => (h << (32 - s)) | (l >>> s);
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// High 32-bit half of a 64-bit right rotate, valid for `s` in `33..63`; `32` uses `rotr32*`.
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const rotrBH = (h, l, s) => (h << (64 - s)) | (l >>> (s - 32));
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// Low 32-bit half of a 64-bit right rotate, valid for `s` in `33..63`; `32` uses `rotr32*`.
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const rotrBL = (h, l, s) => (h >>> (s - 32)) | (l << (64 - s));
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// High 32-bit half of a 64-bit right rotate for `s === 32`; this is just the swapped low half.
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const rotr32H = (_h, l) => l;
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// Low 32-bit half of a 64-bit right rotate for `s === 32`; this is just the swapped high half.
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const rotr32L = (h, _l) => h;
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// High 32-bit half of a 64-bit left rotate, valid for `s` in `1..31`.
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const rotlSH = (h, l, s) => (h << s) | (l >>> (32 - s));
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// Low 32-bit half of a 64-bit left rotate, valid for `s` in `1..31`.
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const rotlSL = (h, l, s) => (l << s) | (h >>> (32 - s));
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// High 32-bit half of a 64-bit left rotate, valid for `s` in `33..63`; `32` uses `rotr32*`.
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const rotlBH = (h, l, s) => (l << (s - 32)) | (h >>> (64 - s));
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// Low 32-bit half of a 64-bit left rotate, valid for `s` in `33..63`; `32` uses `rotr32*`.
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const rotlBL = (h, l, s) => (h << (s - 32)) | (l >>> (64 - s));
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// Add two split 64-bit words and return the split `{ h, l }` sum.
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// JS uses 32-bit signed integers for bitwise operations, so we cannot simply shift the carry out
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// of the low sum and instead use division.
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function add(Ah, Al, Bh, Bl) {
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const l = (Al >>> 0) + (Bl >>> 0);
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return { h: (Ah + Bh + ((l / 2 ** 32) | 0)) | 0, l: l | 0 };
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}
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// Addition with more than 2 elements
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// Unmasked low-word accumulator for 3-way addition; pass the raw result into `add3H(...)`.
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const add3L = (Al, Bl, Cl) => (Al >>> 0) + (Bl >>> 0) + (Cl >>> 0);
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// High-word finalize step for 3-way addition; `low` must be the untruncated output of `add3L(...)`.
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const add3H = (low, Ah, Bh, Ch) => (Ah + Bh + Ch + ((low / 2 ** 32) | 0)) | 0;
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// Unmasked low-word accumulator for 4-way addition; pass the raw result into `add4H(...)`.
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const add4L = (Al, Bl, Cl, Dl) => (Al >>> 0) + (Bl >>> 0) + (Cl >>> 0) + (Dl >>> 0);
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// High-word finalize step for 4-way addition; `low` must be the untruncated output of `add4L(...)`.
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const add4H = (low, Ah, Bh, Ch, Dh) => (Ah + Bh + Ch + Dh + ((low / 2 ** 32) | 0)) | 0;
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// Unmasked low-word accumulator for 5-way addition; pass the raw result into `add5H(...)`.
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const add5L = (Al, Bl, Cl, Dl, El) => (Al >>> 0) + (Bl >>> 0) + (Cl >>> 0) + (Dl >>> 0) + (El >>> 0);
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// High-word finalize step for 5-way addition; `low` must be the untruncated output of `add5L(...)`.
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const add5H = (low, Ah, Bh, Ch, Dh, Eh) => (Ah + Bh + Ch + Dh + Eh + ((low / 2 ** 32) | 0)) | 0;
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// prettier-ignore
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export { add, add3H, add3L, add4H, add4L, add5H, add5L, fromBig, rotlBH, rotlBL, rotlSH, rotlSL, rotr32H, rotr32L, rotrBH, rotrBL, rotrSH, rotrSL, shrSH, shrSL, split, toBig };
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// Canonical grouped namespace for callers that prefer one object.
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// Named exports stay for direct imports.
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// prettier-ignore
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const u64 = {
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fromBig, split, toBig,
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shrSH, shrSL,
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rotrSH, rotrSL, rotrBH, rotrBL,
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rotr32H, rotr32L,
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rotlSH, rotlSL, rotlBH, rotlBL,
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add, add3L, add3H, add4L, add4H, add5H, add5L,
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};
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// Default export mirrors named `u64` for compatibility with object-style imports.
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export default u64;
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//# sourceMappingURL=_u64.js.map
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