From b47aa1446bc638d70a9aea90b10db6c403e55dc4 Mon Sep 17 00:00:00 2001
From: kortschak <dan.kortschak@adelaide.edu.au>
Date: Fri, 16 Jun 2017 11:01:45 +0930
Subject: [PATCH] graph/internal/...: update for int64 IDs

---
 graph/internal/ordered/sort.go       | 12 +++++--
 graph/internal/set/same.go           |  9 +++++
 graph/internal/set/same_appengine.go |  9 +++++
 graph/internal/set/set.go            | 51 ++++++++++++++++++++++++++--
 graph/internal/set/set_test.go       |  4 +--
 5 files changed, 79 insertions(+), 6 deletions(-)

diff --git a/graph/internal/ordered/sort.go b/graph/internal/ordered/sort.go
index 742d67ec..e0cce8ef 100644
--- a/graph/internal/ordered/sort.go
+++ b/graph/internal/ordered/sort.go
@@ -16,8 +16,8 @@ func (n ByID) Less(i, j int) bool { return n[i].ID() < n[j].ID() }
 func (n ByID) Swap(i, j int)      { n[i], n[j] = n[j], n[i] }
 
 // BySliceValues implements the sort.Interface sorting a slice of
-// []int lexically by the values of the []int.
-type BySliceValues [][]int
+// []int64 lexically by the values of the []int64.
+type BySliceValues [][]int64
 
 func (c BySliceValues) Len() int { return len(c) }
 func (c BySliceValues) Less(i, j int) bool {
@@ -60,3 +60,11 @@ func (c BySliceIDs) Less(i, j int) bool {
 	return len(a) < len(b)
 }
 func (c BySliceIDs) Swap(i, j int) { c[i], c[j] = c[j], c[i] }
+
+// Int64s implements the sort.Interface sorting a slice of
+// int64.
+type Int64s []int64
+
+func (s Int64s) Len() int           { return len(s) }
+func (s Int64s) Less(i, j int) bool { return s[i] < s[j] }
+func (s Int64s) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
diff --git a/graph/internal/set/same.go b/graph/internal/set/same.go
index 446e0ac3..c776dc32 100644
--- a/graph/internal/set/same.go
+++ b/graph/internal/set/same.go
@@ -25,3 +25,12 @@ func same(a, b Nodes) bool {
 func intsSame(a, b Ints) bool {
 	return *(*uintptr)(unsafe.Pointer(&a)) == *(*uintptr)(unsafe.Pointer(&b))
 }
+
+// int64sSame determines whether two sets are backed by the same store. In the
+// current implementation using hash maps it makes use of the fact that
+// hash maps are passed as a pointer to a runtime Hmap struct. A map is
+// not seen by the runtime as a pointer though, so we use unsafe to get
+// the maps' pointer values to compare.
+func int64sSame(a, b Int64s) bool {
+	return *(*uintptr)(unsafe.Pointer(&a)) == *(*uintptr)(unsafe.Pointer(&b))
+}
diff --git a/graph/internal/set/same_appengine.go b/graph/internal/set/same_appengine.go
index 00d095a0..082ed265 100644
--- a/graph/internal/set/same_appengine.go
+++ b/graph/internal/set/same_appengine.go
@@ -25,3 +25,12 @@ func same(a, b Nodes) bool {
 func intsSame(a, b Ints) bool {
 	return reflect.ValueOf(a).Pointer() == reflect.ValueOf(b).Pointer()
 }
+
+// int64sSame determines whether two sets are backed by the same store. In the
+// current implementation using hash maps it makes use of the fact that
+// hash maps are passed as a pointer to a runtime Hmap struct. A map is
+// not seen by the runtime as a pointer though, so we use reflect to get
+// the maps' pointer values to compare.
+func int64sSame(a, b Int64s) bool {
+	return reflect.ValueOf(a).Pointer() == reflect.ValueOf(b).Pointer()
+}
diff --git a/graph/internal/set/set.go b/graph/internal/set/set.go
index b9587776..1397dabb 100644
--- a/graph/internal/set/set.go
+++ b/graph/internal/set/set.go
@@ -7,7 +7,7 @@ package set // import "gonum.org/v1/gonum/graph/internal/set"
 
 import "gonum.org/v1/gonum/graph"
 
-// Ints is a set of integer identifiers.
+// Ints is a set of int identifiers.
 type Ints map[int]struct{}
 
 // The simple accessor methods for Ints are provided to allow ease of
@@ -54,8 +54,55 @@ func IntsEqual(a, b Ints) bool {
 	return true
 }
 
+// Int64s is a set of int64 identifiers.
+type Int64s map[int64]struct{}
+
+// The simple accessor methods for Ints are provided to allow ease of
+// implementation change should the need arise.
+
+// Add inserts an element into the set.
+func (s Int64s) Add(e int64) {
+	s[e] = struct{}{}
+}
+
+// Has reports the existence of the element in the set.
+func (s Int64s) Has(e int64) bool {
+	_, ok := s[e]
+	return ok
+}
+
+// Remove deletes the specified element from the set.
+func (s Int64s) Remove(e int64) {
+	delete(s, e)
+}
+
+// Count reports the number of elements stored in the set.
+func (s Int64s) Count() int {
+	return len(s)
+}
+
+// Int64sEqual reports set equality between the parameters. Sets are equal if
+// and only if they have the same elements.
+func Int64sEqual(a, b Int64s) bool {
+	if int64sSame(a, b) {
+		return true
+	}
+
+	if len(a) != len(b) {
+		return false
+	}
+
+	for e := range a {
+		if _, ok := b[e]; !ok {
+			return false
+		}
+	}
+
+	return true
+}
+
 // Nodes is a set of nodes keyed in their integer identifiers.
-type Nodes map[int]graph.Node
+type Nodes map[int64]graph.Node
 
 // The simple accessor methods for Nodes are provided to allow ease of
 // implementation change should the need arise.
diff --git a/graph/internal/set/set_test.go b/graph/internal/set/set_test.go
index 13984e14..f665b398 100644
--- a/graph/internal/set/set_test.go
+++ b/graph/internal/set/set_test.go
@@ -6,9 +6,9 @@ package set
 
 import "testing"
 
-type node int
+type node int64
 
-func (n node) ID() int { return int(n) }
+func (n node) ID() int64 { return int64(n) }
 
 // count reports the number of elements stored in the node set.
 func (s Nodes) count() int {