From f48bfee577f1028a2d720d022791631fd064c1cb Mon Sep 17 00:00:00 2001
From: Daniel Lemire <lemire@gmail.com>
Date: Mon, 9 May 2022 16:15:50 -0400
Subject: [PATCH] Fixing duplicate issue.

---
 binaryfusefilter.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/binaryfusefilter.go b/binaryfusefilter.go
index 5c0d074..22a6bc1 100644
--- a/binaryfusefilter.go
+++ b/binaryfusefilter.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"math"
 	"math/bits"
+	"sort"
 )
 
 type BinaryFuse8 struct {
@@ -86,6 +87,7 @@ func mod3(x uint8) uint8 {
 
 // PopulateBinaryFuse8 fills a BinaryFuse8 filter with provided keys.
 // The function may return an error after too many iterations: it is unlikely.
+// If your input has duplicates, it may get sorted.
 func PopulateBinaryFuse8(keys []uint64) (*BinaryFuse8, error) {
 	size := uint32(len(keys))
 	filter := &BinaryFuse8{}
@@ -240,6 +242,12 @@ func PopulateBinaryFuse8(keys []uint64) (*BinaryFuse8, error) {
 			// Success
 			size = stacksize
 			break
+		} else if duplicates > 0 {
+			// Duplicates were found, but we did not
+			// manage to remove them all. We may simply sort the key to
+			// solve the issue. This will run in time O(n log n) and it
+			// mutates the input.
+			sort.Slice(keys, func(i, j int) bool { return keys[i] < keys[j] })
 		}
 		for i := uint32(0); i < size; i++ {
 			reverseOrder[i] = 0