From 9d91aa6c1f226df3d66aa6f1effc6c2b1f17a933 Mon Sep 17 00:00:00 2001
From: Kegan Dougal <kegan@matrix.org>
Date: Wed, 8 Mar 2017 16:25:55 +0000
Subject: [PATCH] Update util dep

---
 .../src/github.com/matrix-org/util/unique.go  | 57 +++++++++++
 .../github.com/matrix-org/util/unique_test.go | 96 +++++++++++++++++++
 2 files changed, 153 insertions(+)
 create mode 100644 vendor/src/github.com/matrix-org/util/unique.go
 create mode 100644 vendor/src/github.com/matrix-org/util/unique_test.go

diff --git a/vendor/src/github.com/matrix-org/util/unique.go b/vendor/src/github.com/matrix-org/util/unique.go
new file mode 100644
index 000000000..401c55609
--- /dev/null
+++ b/vendor/src/github.com/matrix-org/util/unique.go
@@ -0,0 +1,57 @@
+package util
+
+import (
+	"fmt"
+	"sort"
+)
+
+// Unique removes duplicate items from a sorted list in place.
+// Takes the same interface as sort.Sort
+// Returns the length of the data without duplicates
+// Uses the last occurrence of a duplicate.
+// O(n).
+func Unique(data sort.Interface) int {
+	if !sort.IsSorted(data) {
+		panic(fmt.Errorf("util: the input to Unique() must be sorted"))
+	}
+
+	if data.Len() == 0 {
+		return 0
+	}
+	length := data.Len()
+	// j is the next index to output an element to.
+	j := 0
+	for i := 1; i < length; i++ {
+		// If the previous element is less than this element then they are
+		// not equal. Otherwise they must be equal because the list is sorted.
+		// If they are equal then we move onto the next element.
+		if data.Less(i-1, i) {
+			// "Write" the previous element to the output position by swapping
+			// the elements.
+			// Note that if the list has no duplicates then i-1 == j so the
+			// swap does nothing. (This assumes that data.Swap(a,b) nops if a==b)
+			data.Swap(i-1, j)
+			// Advance to the next output position in the list.
+			j++
+		}
+	}
+	// Output the last element.
+	data.Swap(length-1, j)
+	return j + 1
+}
+
+// SortAndUnique sorts a list and removes duplicate entries in place.
+// Takes the same interface as sort.Sort
+// Returns the length of the data without duplicates
+// Uses the last occurrence of a duplicate.
+// O(nlog(n))
+func SortAndUnique(data sort.Interface) int {
+	sort.Sort(data)
+	return Unique(data)
+}
+
+// UniqueStrings turns a list of strings into a sorted list of unique strings.
+// O(nlog(n))
+func UniqueStrings(strings []string) []string {
+	return strings[:SortAndUnique(sort.StringSlice(strings))]
+}
diff --git a/vendor/src/github.com/matrix-org/util/unique_test.go b/vendor/src/github.com/matrix-org/util/unique_test.go
new file mode 100644
index 000000000..721624d37
--- /dev/null
+++ b/vendor/src/github.com/matrix-org/util/unique_test.go
@@ -0,0 +1,96 @@
+package util
+
+import (
+	"sort"
+	"testing"
+)
+
+type sortBytes []byte
+
+func (s sortBytes) Len() int           { return len(s) }
+func (s sortBytes) Less(i, j int) bool { return s[i] < s[j] }
+func (s sortBytes) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
+func TestUnique(t *testing.T) {
+	testCases := []struct {
+		Input string
+		Want  string
+	}{
+		{"", ""},
+		{"abc", "abc"},
+		{"aaabbbccc", "abc"},
+	}
+
+	for _, test := range testCases {
+		input := []byte(test.Input)
+		want := string(test.Want)
+		got := string(input[:Unique(sortBytes(input))])
+		if got != want {
+			t.Fatal("Wanted ", want, " got ", got)
+		}
+	}
+}
+
+type sortByFirstByte []string
+
+func (s sortByFirstByte) Len() int           { return len(s) }
+func (s sortByFirstByte) Less(i, j int) bool { return s[i][0] < s[j][0] }
+func (s sortByFirstByte) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
+func TestUniquePicksLastDuplicate(t *testing.T) {
+	input := []string{
+		"aardvark",
+		"avacado",
+		"cat",
+		"cucumber",
+	}
+	want := []string{
+		"avacado",
+		"cucumber",
+	}
+	got := input[:Unique(sortByFirstByte(input))]
+
+	if len(want) != len(got) {
+		t.Errorf("Wanted %#v got %#v", want, got)
+	}
+	for i := range want {
+		if want[i] != got[i] {
+			t.Errorf("Wanted %#v got %#v", want, got)
+		}
+	}
+}
+
+func TestUniquePanicsIfNotSorted(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Error("Expected Unique() to panic on unsorted input but it didn't")
+		}
+	}()
+	Unique(sort.StringSlice{"out", "of", "order"})
+}
+
+func TestUniqueStrings(t *testing.T) {
+	input := []string{
+		"badger", "badger", "badger", "badger",
+		"badger", "badger", "badger", "badger",
+		"badger", "badger", "badger", "badger",
+		"mushroom", "mushroom",
+		"badger", "badger", "badger", "badger",
+		"badger", "badger", "badger", "badger",
+		"badger", "badger", "badger", "badger",
+		"snake", "snake",
+	}
+
+	want := []string{"badger", "mushroom", "snake"}
+
+	got := UniqueStrings(input)
+
+	if len(want) != len(got) {
+		t.Errorf("Wanted %#v got %#v", want, got)
+	}
+	for i := range want {
+		if want[i] != got[i] {
+			t.Errorf("Wanted %#v got %#v", want, got)
+		}
+	}
+}