From 16ff6e989e170ea0c3a0dcda48a2da2a0d40d188 Mon Sep 17 00:00:00 2001
From: "Ric (Ryszard) Szopa" <ryszard.szopa@gmail.com>
Date: Sun, 8 Sep 2013 01:34:20 -0700
Subject: [PATCH] Add StatefulIterator, fix bug in DataCallbackIterator.

---
 iterator.go      | 58 ++++++++++++++++++++++++++++++++++++++++++++++--
 iterator_test.go | 48 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+), 2 deletions(-)

diff --git a/iterator.go b/iterator.go
index e5ffe8f..d931e5d 100644
--- a/iterator.go
+++ b/iterator.go
@@ -38,8 +38,8 @@ func IntCallbackIterator(cb func(int)) {
 	}
 }
 func DataCallbackIterator(cb func(int)) {
-	for _, val := range int_data {
-		cb(val)
+	for _, val := range struct_data {
+		cb(val.foo)
 	}
 }
 
@@ -109,3 +109,57 @@ func DataClosureIterator() (func() (int, bool), bool) {
 		return struct_data[prev_idx].foo, (idx < data_len)
 	}, (idx < data_len)
 }
+
+type StatefulIterator interface {
+	Value() int
+	Next() bool
+}
+
+type dataStatefulIterator struct {
+	current int
+	data    []*Data
+}
+
+func NewDataStatefulIterator(data []*Data) *dataStatefulIterator {
+	return &dataStatefulIterator{data: data, current: -1}
+}
+
+func NewDataStatefulIteratorInterface(data []*Data) StatefulIterator {
+	return &dataStatefulIterator{data: data, current: -1}
+}
+
+func (it *dataStatefulIterator) Value() int {
+	return it.data[it.current].foo
+}
+func (it *dataStatefulIterator) Next() bool {
+	it.current++
+	if it.current >= len(it.data) {
+		return false
+	}
+	return true
+}
+
+type intStatefulIterator struct {
+	current int
+	data    []int
+}
+
+func (it *intStatefulIterator) Value() int {
+	return it.data[it.current]
+}
+func (it *intStatefulIterator) Next() bool {
+	it.current++
+
+	if it.current >= len(it.data) {
+		return false
+	}
+	return true
+}
+
+func NewIntStatefulIterator(data []int) *intStatefulIterator {
+	return &intStatefulIterator{data: data, current: -1}
+}
+
+func NewIntStatefulIteratorInterface(data []int) StatefulIterator {
+	return &intStatefulIterator{data: data, current: -1}
+}
diff --git a/iterator_test.go b/iterator_test.go
index 82a40b3..080eb6c 100644
--- a/iterator_test.go
+++ b/iterator_test.go
@@ -91,3 +91,51 @@ func BenchmarkDataClosureIterator(b *testing.B) {
 		}
 	}
 }
+
+func BenchmarkIntStatefulIterator(b *testing.B) {
+	InitInts()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		var sum int = 0
+		it := NewIntStatefulIterator(int_data)
+		for it.Next() {
+			sum += it.Value()
+		}
+	}
+}
+
+func BenchmarkDataStatefulIterator(b *testing.B) {
+	InitData()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		var sum int = 0
+		it := NewDataStatefulIterator(struct_data)
+		for it.Next() {
+			sum += it.Value()
+		}
+	}
+}
+
+func BenchmarkIntStatefulIteratorInterface(b *testing.B) {
+	InitInts()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		var sum int = 0
+		it := NewIntStatefulIteratorInterface(int_data)
+		for it.Next() {
+			sum += it.Value()
+		}
+	}
+}
+
+func BenchmarkDataStatefulIteratorInterface(b *testing.B) {
+	InitData()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		var sum int = 0
+		it := NewDataStatefulIteratorInterface(struct_data)
+		for it.Next() {
+			sum += it.Value()
+		}
+	}
+}