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lib/mod.js

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+const peq = new Uint32Array(0x10000);
+const myers_32 = (a, b) => {
+    const n = a.length;
+    const m = b.length;
+    const lst = 1 << (n - 1);
+    let pv = -1;
+    let mv = 0;
+    let sc = n;
+    let i = n;
+    while (i--) {
+        peq[a.charCodeAt(i)] |= 1 << i;
+    }
+    for (i = 0; i < m; i++) {
+        let eq = peq[b.charCodeAt(i)];
+        const xv = eq | mv;
+        eq |= ((eq & pv) + pv) ^ pv;
+        mv |= ~(eq | pv);
+        pv &= eq;
+        if (mv & lst) {
+            sc++;
+        }
+        if (pv & lst) {
+            sc--;
+        }
+        mv = (mv << 1) | 1;
+        pv = (pv << 1) | ~(xv | mv);
+        mv &= xv;
+    }
+    i = n;
+    while (i--) {
+        peq[a.charCodeAt(i)] = 0;
+    }
+    return sc;
+};
+const myers_x = (b, a) => {
+    const n = a.length;
+    const m = b.length;
+    const mhc = [];
+    const phc = [];
+    const hsize = Math.ceil(n / 32);
+    const vsize = Math.ceil(m / 32);
+    for (let i = 0; i < hsize; i++) {
+        phc[i] = -1;
+        mhc[i] = 0;
+    }
+    let j = 0;
+    for (; j < vsize - 1; j++) {
+        let mv = 0;
+        let pv = -1;
+        const start = j * 32;
+        const vlen = Math.min(32, m) + start;
+        for (let k = start; k < vlen; k++) {
+            peq[b.charCodeAt(k)] |= 1 << k;
+        }
+        for (let i = 0; i < n; i++) {
+            const eq = peq[a.charCodeAt(i)];
+            const pb = (phc[(i / 32) | 0] >>> i) & 1;
+            const mb = (mhc[(i / 32) | 0] >>> i) & 1;
+            const xv = eq | mv;
+            const xh = ((((eq | mb) & pv) + pv) ^ pv) | eq | mb;
+            let ph = mv | ~(xh | pv);
+            let mh = pv & xh;
+            if ((ph >>> 31) ^ pb) {
+                phc[(i / 32) | 0] ^= 1 << i;
+            }
+            if ((mh >>> 31) ^ mb) {
+                mhc[(i / 32) | 0] ^= 1 << i;
+            }
+            ph = (ph << 1) | pb;
+            mh = (mh << 1) | mb;
+            pv = mh | ~(xv | ph);
+            mv = ph & xv;
+        }
+        for (let k = start; k < vlen; k++) {
+            peq[b.charCodeAt(k)] = 0;
+        }
+    }
+    let mv = 0;
+    let pv = -1;
+    const start = j * 32;
+    const vlen = Math.min(32, m - start) + start;
+    for (let k = start; k < vlen; k++) {
+        peq[b.charCodeAt(k)] |= 1 << k;
+    }
+    let score = m;
+    for (let i = 0; i < n; i++) {
+        const eq = peq[a.charCodeAt(i)];
+        const pb = (phc[(i / 32) | 0] >>> i) & 1;
+        const mb = (mhc[(i / 32) | 0] >>> i) & 1;
+        const xv = eq | mv;
+        const xh = ((((eq | mb) & pv) + pv) ^ pv) | eq | mb;
+        let ph = mv | ~(xh | pv);
+        let mh = pv & xh;
+        score += (ph >>> (m - 1)) & 1;
+        score -= (mh >>> (m - 1)) & 1;
+        if ((ph >>> 31) ^ pb) {
+            phc[(i / 32) | 0] ^= 1 << i;
+        }
+        if ((mh >>> 31) ^ mb) {
+            mhc[(i / 32) | 0] ^= 1 << i;
+        }
+        ph = (ph << 1) | pb;
+        mh = (mh << 1) | mb;
+        pv = mh | ~(xv | ph);
+        mv = ph & xv;
+    }
+    for (let k = start; k < vlen; k++) {
+        peq[b.charCodeAt(k)] = 0;
+    }
+    return score;
+};
+const distance = (a, b) => {
+    if (a.length < b.length) {
+        const tmp = b;
+        b = a;
+        a = tmp;
+    }
+    if (b.length === 0) {
+        return a.length;
+    }
+    if (a.length <= 32) {
+        return myers_32(a, b);
+    }
+    return myers_x(a, b);
+};
+const closest = (str, arr) => {
+    let min_distance = Infinity;
+    let min_index = 0;
+    for (let i = 0; i < arr.length; i++) {
+        const dist = distance(str, arr[i]);
+        if (dist < min_distance) {
+            min_distance = dist;
+            min_index = i;
+        }
+    }
+    return arr[min_index];
+};
+export { closest, distance };