use quicksort instead of default system sort (#413)

client/src/util/typedCrossfilter/sort.js

@@ -0,0 +1,100 @@
+const SmallArray = 32;
+
+function insertionsort(a, lo, hi) {
+  for (let i = lo + 1; i < hi + 1; i += 1) {
+    const x = a[i];
+    let j;
+    for (j = i; j > lo && a[j - 1] > x; j -= 1) {
+      a[j] = a[j - 1];
+    }
+    a[j] = x;
+  }
+  return a;
+}
+
+function insertionsortIndirect(a, s, lo, hi) {
+  for (let i = lo + 1; i < hi + 1; i += 1) {
+    const x = a[i];
+    const t = s[x];
+    let j;
+    for (j = i; j > lo && s[a[j - 1]] > t; j -= 1) {
+      a[j] = a[j - 1];
+    }
+    a[j] = x;
+  }
+  return a;
+}
+
+function quicksort(a, lo, hi) {
+  if (hi - lo < SmallArray) {
+    return insertionsort(a, lo, hi);
+  }
+  if (lo < hi) {
+    // partition
+    const mid = Math.floor((lo + hi) / 2);
+    const p = a[mid];
+    let i = lo - 1;
+    let j = hi + 1;
+    while (i < j) {
+      do {
+        i += 1;
+      } while (a[i] < p);
+      do {
+        j -= 1;
+      } while (a[j] > p);
+      if (i < j) {
+        const tmp = a[i];
+        a[i] = a[j];
+        a[j] = tmp;
+      }
+    }
+    // sort
+    quicksort(a, lo, j);
+    quicksort(a, j + 1, hi);
+  }
+  return a;
+}
+
+function quicksortIndirect(a, s, lo, hi) {
+  if (hi - lo < SmallArray) {
+    return insertionsortIndirect(a, s, lo, hi);
+  }
+  if (lo < hi) {
+    // partition
+    const mid = Math.floor((lo + hi) / 2);
+    const p = a[mid];
+    const t = s[p];
+    let i = lo - 1;
+    let j = hi + 1;
+    while (i < j) {
+      do {
+        i += 1;
+      } while (s[a[i]] < t);
+      do {
+        j -= 1;
+      } while (s[a[j]] > t);
+      if (i < j) {
+        const tmp = a[i];
+        a[i] = a[j];
+        a[j] = tmp;
+      }
+    }
+    // sort
+    quicksortIndirect(a, s, lo, j);
+    quicksortIndirect(a, s, j + 1, hi);
+  }
+  return a;
+}
+
+// Convenience wrappers
+export function sort(arr, comparator = undefined) {
+  if (comparator !== undefined) {
+    // XXX for now
+    return arr.sort(arr, comparator);
+  }
+  return quicksort(arr, 0, arr.length - 1);
+}
+
+export function sortIndex(index, source) {
+  return quicksortIndirect(index, source, 0, index.length - 1);
+}

client/src/util/typedCrossfilter/util.js

@@ -1,6 +1,8 @@
 // jshint esversion: 6
 /* eslint no-bitwise: "off" */
 
+import { sortIndex } from "./sort";
+
 /*
     Utility functions, private to this module.
 */
@@ -31,7 +33,7 @@ export function sliceByIndex(src, index) {
 
 export function makeSortIndex(src) {
   const index = fillRange(new Uint32Array(src.length));
-  index.sort((a, b) => src[a] - src[b]);
+  sortIndex(index, src);
   return index;
 }