From 2603c67e10effc149911ced40adece6026593e4b Mon Sep 17 00:00:00 2001
From: Will Charczuk <will.charczuk@gmail.com>
Date: Mon, 18 Jul 2016 12:57:10 -0700
Subject: [PATCH] adding lastvalueprovider interface and relevant methods.

---
 continuous_series.go |  5 +++++
 ema_series.go        |  4 ++--
 sma_series.go        |  4 ++--
 time_series.go       |  9 ++++++++-
 value_provider.go    | 10 ++++++++++
 5 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/continuous_series.go b/continuous_series.go
index 57c145b..fe0581d 100644
--- a/continuous_series.go
+++ b/continuous_series.go
@@ -31,6 +31,11 @@ func (cs ContinuousSeries) GetValue(index int) (float64, float64) {
 	return cs.XValues[index], cs.YValues[index]
 }
 
+// GetLastValue gets the last value.
+func (cs ContinuousSeries) GetLastValue() (float64, float64) {
+	return cs.XValues[len(cs.XValues)-1], cs.YValues[len(cs.YValues)-1]
+}
+
 // GetValueFormatters returns value formatter defaults for the series.
 func (cs ContinuousSeries) GetValueFormatters() (x, y ValueFormatter) {
 	x = FloatValueFormatter
diff --git a/ema_series.go b/ema_series.go
index d0c58f8..b435751 100644
--- a/ema_series.go
+++ b/ema_series.go
@@ -52,7 +52,7 @@ func (ema EMASeries) GetSigma() float64 {
 }
 
 // GetValue gets a value at a given index.
-func (ema EMASeries) GetValue(index int) (x float64, y float64) {
+func (ema EMASeries) GetValue(index int) (x, y float64) {
 	if ema.InnerSeries == nil {
 		return
 	}
@@ -64,7 +64,7 @@ func (ema EMASeries) GetValue(index int) (x float64, y float64) {
 
 // GetLastValue computes the last moving average value but walking back window size samples,
 // and recomputing the last moving average chunk.
-func (ema EMASeries) GetLastValue() (x float64, y float64) {
+func (ema EMASeries) GetLastValue() (x, y float64) {
 	if ema.InnerSeries == nil {
 		return
 	}
diff --git a/sma_series.go b/sma_series.go
index 89f5344..ca43e2b 100644
--- a/sma_series.go
+++ b/sma_series.go
@@ -36,7 +36,7 @@ func (sma SMASeries) Len() int {
 }
 
 // GetValue gets a value at a given index.
-func (sma SMASeries) GetValue(index int) (x float64, y float64) {
+func (sma SMASeries) GetValue(index int) (x, y float64) {
 	if sma.InnerSeries == nil {
 		return
 	}
@@ -48,7 +48,7 @@ func (sma SMASeries) GetValue(index int) (x float64, y float64) {
 
 // GetLastValue computes the last moving average value but walking back window size samples,
 // and recomputing the last moving average chunk.
-func (sma SMASeries) GetLastValue() (x float64, y float64) {
+func (sma SMASeries) GetLastValue() (x, y float64) {
 	if sma.InnerSeries == nil {
 		return
 	}
diff --git a/time_series.go b/time_series.go
index becf213..37ba6b9 100644
--- a/time_series.go
+++ b/time_series.go
@@ -29,12 +29,19 @@ func (ts TimeSeries) Len() int {
 }
 
 // GetValue gets a value at a given index.
-func (ts TimeSeries) GetValue(index int) (x float64, y float64) {
+func (ts TimeSeries) GetValue(index int) (x, y float64) {
 	x = TimeToFloat64(ts.XValues[index])
 	y = ts.YValues[index]
 	return
 }
 
+// GetLastValue gets the last value.
+func (ts TimeSeries) GetLastValue() (x, y float64) {
+	x = TimeToFloat64(ts.XValues[len(ts.XValues)-1])
+	y = ts.YValues[len(ts.YValues)-1]
+	return
+}
+
 // GetValueFormatters returns value formatter defaults for the series.
 func (ts TimeSeries) GetValueFormatters() (x, y ValueFormatter) {
 	x = TimeValueFormatter
diff --git a/value_provider.go b/value_provider.go
index 1ff8e82..6fceeb0 100644
--- a/value_provider.go
+++ b/value_provider.go
@@ -11,3 +11,13 @@ type BoundedValueProvider interface {
 	Len() int
 	GetBoundedValue(index int) (x, y1, y2 float64)
 }
+
+// LastValueProvider is a special type of value provider that can return it's (potentially computed) last value.
+type LastValueProvider interface {
+	GetLastValue() (x, y float64)
+}
+
+// BoundedLastValueProvider is a special type of value provider that can return it's (potentially computed) bounded last value.
+type BoundedLastValueProvider interface {
+	GetBoundedLastValue(index int) (x, y1, y2 float64)
+}