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backend/node_modules/mnemonist/utils/hash-tables.js

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+/* eslint no-constant-condition: 0 */
+/**
+ * Mnemonist Hashtable Helpers
+ * ============================
+ *
+ * Miscellaneous helpers helper function dealing with hashtables.
+ */
+function jenkinsInt32(a) {
+
+  a = (a + 0x7ed55d16) + (a << 12);
+  a = (a ^ 0xc761c23c) ^ (a >> 19);
+  a = (a + 0x165667b1) + (a << 5);
+  a = (a + 0xd3a2646c) ^ (a << 9);
+  a = (a + 0xfd7046c5) + (a << 3);
+  a = (a ^ 0xb55a4f09) ^ (a >> 16);
+
+  return a;
+}
+
+function linearProbingGet(hash, keys, values, key) {
+  var n = keys.length,
+      j = hash(key) & (n - 1),
+      i = j;
+
+  var c;
+
+  while (true) {
+    c = keys[i];
+
+    if (c === key)
+      return values[i];
+
+    else if (c === 0)
+      return;
+
+    // Handling wrapping around
+    i += 1;
+    i %= n;
+
+    // Full turn
+    if (i === j)
+      return;
+  }
+}
+
+function linearProbingHas(hash, keys, key) {
+  var n = keys.length,
+      j = hash(key) & (n - 1),
+      i = j;
+
+  var c;
+
+  while (true) {
+    c = keys[i];
+
+    if (c === key)
+      return true;
+
+    else if (c === 0)
+      return false;
+
+    // Handling wrapping around
+    i += 1;
+    i %= n;
+
+    // Full turn
+    if (i === j)
+      return false;
+  }
+}
+
+function linearProbingSet(hash, keys, values, key, value) {
+  var n = keys.length,
+      j = hash(key) & (n - 1),
+      i = j;
+
+  var c;
+
+  while (true) {
+    c = keys[i];
+
+    if (c === 0 || c === key)
+      break;
+
+    // Handling wrapping around
+    i += 1;
+    i %= n;
+
+    // Full turn
+    if (i === j)
+      throw new Error('mnemonist/utils/hash-tables.linearProbingSet: table is full.');
+  }
+
+  keys[i] = key;
+  values[i] = value;
+}
+
+module.exports = {
+  hashes: {
+    jenkinsInt32: jenkinsInt32
+  },
+  linearProbing: {
+    get: linearProbingGet,
+    has: linearProbingHas,
+    set: linearProbingSet
+  }
+};