expose circular buffer

adxr.go

@@ -6,22 +6,22 @@ package tart
 type AdxR struct {
 	n    int64
 	adx  *Adx
-	hist *cBuf
+	hist *CBuf
 }
 
 func NewAdxR(n int64) *AdxR {
 	return &AdxR{
 		n:    n,
 		adx:  NewAdx(n),
-		hist: newCBuf(n - 1),
+		hist: NewCBuf(n - 1),
 	}
 }
 
 func (a *AdxR) Update(h, l, c float64) float64 {
 	v := a.adx.Update(h, l, c)
-	old := a.hist.append(v)
+	old := a.hist.Append(v)
 
-	if a.hist.size() <= 3*a.n-2 {
+	if a.hist.Size() <= 3*a.n-2 {
 		return 0
 	}
 
@@ -33,7 +33,7 @@ func (a *AdxR) InitPeriod() int64 {
 }
 
 func (a *AdxR) Valid() bool {
-	return a.hist.size() > a.InitPeriod()
+	return a.hist.Size() > a.InitPeriod()
 }
 
 // Average Directional Movement Index Rating (ADXR) is a simple

cbuf.go

@@ -1,24 +1,25 @@
 package tart
 
 // circular buffer maintaining fixed sized history
-type cBuf struct {
+type CBuf struct {
 	n      int64
 	hist   []float64
 	oldest int64
 	newest int64
 	sz     int64
 }
 
-func newCBuf(n int64) *cBuf {
-	return &cBuf{
+func NewCBuf(n int64) *CBuf {
+	return &CBuf{
 		n:      n,
 		hist:   make([]float64, n),
 		oldest: 0,
 		newest: n - 1,
 	}
 }
 
-func (c *cBuf) append(v float64) float64 {
+// Append latest value and return oldest one
+func (c *CBuf) Append(v float64) float64 {
 	old := c.hist[c.oldest]
 	c.hist[c.oldest] = v
 	c.newest = c.oldest
@@ -27,39 +28,44 @@ func (c *cBuf) append(v float64) float64 {
 	return old
 }
 
-func (c *cBuf) size() int64 {
+// Number of values appended
+func (c *CBuf) Size() int64 {
 	return c.sz
 }
 
-func (c *cBuf) indexToSeq(idx int64) int64 {
+// From circular buf position to total sequence index
+func (c *CBuf) IndexToSeq(idx int64) int64 {
 	if idx < c.oldest {
 		return c.sz - (c.oldest - idx)
 	} else {
 		return c.sz - c.n + (idx - c.oldest)
 	}
 }
 
-func (c *cBuf) newestIndex() int64 {
+// Index of the latest value
+func (c *CBuf) NewestIndex() int64 {
 	return c.newest
 }
 
-func (c *cBuf) oldestIndex() int64 {
+// Index of the oldest value
+func (c *CBuf) OldestIndex() int64 {
 	return c.oldest
 }
 
 // nthNewest(0) = newest
 // nthNewest(1) = 2nd newest
-func (c *cBuf) nthNewest(offset int64) float64 {
+func (c *CBuf) NthNewest(offset int64) float64 {
 	return c.hist[(c.newest+c.n-offset)%c.n]
 }
 
 // nthOldest(0) = oldest
 // nthOldest(1) = 2nd oldest
-func (c *cBuf) nthOldest(offset int64) float64 {
+func (c *CBuf) NthOldest(offset int64) float64 {
 	return c.hist[(c.oldest+offset)%c.n]
 }
 
-func (c *cBuf) min() (int64, float64) {
+// Min value in buf
+func (c *CBuf) Min() (int64, float64) {
 	min := c.hist[0]
 	minIdx := int64(0)
 	for i := 1; i < len(c.hist); i++ {
@@ -71,7 +77,8 @@ func (c *cBuf) min() (int64, float64) {
 	return minIdx, min
 }
 
-func (c *cBuf) max() (int64, float64) {
+// Max value in buf
+func (c *CBuf) Max() (int64, float64) {
 	max := c.hist[0]
 	maxIdx := int64(0)
 	for i := 1; i < len(c.hist); i++ {
@@ -83,7 +90,8 @@ func (c *cBuf) max() (int64, float64) {
 	return maxIdx, max
 }
 
-func (c *cBuf) iter(fn func(v float64)) {
+// Iterate through buf elements and call function for each
+func (c *CBuf) Iter(fn func(v float64)) {
 	idx := c.oldest
 	for i := int64(0); i < c.n; i++ {
 		fn(c.hist[idx])

cbuf_test.go

@@ -7,34 +7,34 @@ import (
 )
 
 func TestCBuf(t *testing.T) {
-	c := newCBuf(7)
+	c := NewCBuf(7)
 	for v := 1.0; v < 10; v++ {
-		c.append(v)
-		assert.EqualValues(t, v, c.nthNewest(0))
-		assert.EqualValues(t, v, c.size())
-		assert.EqualValues(t, int(v-1)%7, c.newestIndex())
-		assert.EqualValues(t, int(v)%7, c.oldestIndex())
+		c.Append(v)
+		assert.EqualValues(t, v, c.NthNewest(0))
+		assert.EqualValues(t, v, c.Size())
+		assert.EqualValues(t, int(v-1)%7, c.NewestIndex())
+		assert.EqualValues(t, int(v)%7, c.OldestIndex())
 	}
 
 	// 8,9,3,4,5,6,7
 	//   ^
 	// newest
 	expected := []float64{9, 8, 7, 6, 5, 4, 3}
 	for idx, ev := range expected {
-		assert.EqualValues(t, ev, c.nthNewest(int64(idx)))
+		assert.EqualValues(t, ev, c.NthNewest(int64(idx)))
 	}
 	expected = []float64{3, 4, 5, 6, 7, 8, 9}
 	for idx, ev := range expected {
-		assert.EqualValues(t, ev, c.nthOldest(int64(idx)))
+		assert.EqualValues(t, ev, c.NthOldest(int64(idx)))
 	}
 
-	assert.EqualValues(t, 2, c.indexToSeq(2))
-	assert.EqualValues(t, 6, c.indexToSeq(6))
-	assert.EqualValues(t, 7, c.indexToSeq(0))
-	assert.EqualValues(t, 8, c.indexToSeq(1))
+	assert.EqualValues(t, 2, c.IndexToSeq(2))
+	assert.EqualValues(t, 6, c.IndexToSeq(6))
+	assert.EqualValues(t, 7, c.IndexToSeq(0))
+	assert.EqualValues(t, 8, c.IndexToSeq(1))
 
 	sum := float64(0)
-	c.iter(func(v float64) {
+	c.Iter(func(v float64) {
 		sum += v
 	})
 	assert.EqualValues(t, 42, sum)

dev.go

@@ -7,29 +7,29 @@ import (
 // Average deviation from mean value.
 type Dev struct {
 	n    int64
-	hist *cBuf
+	hist *CBuf
 	sum  float64
 }
 
 func NewDev(n int64) *Dev {
 	return &Dev{
 		n:    n,
-		hist: newCBuf(n),
+		hist: NewCBuf(n),
 		sum:  0,
 	}
 }
 
 func (d *Dev) Update(v float64) float64 {
-	old := d.hist.append(v)
+	old := d.hist.Append(v)
 	d.sum += v - old
 
-	if d.hist.size() < d.n {
+	if d.hist.Size() < d.n {
 		return 0
 	}
 
 	mean := d.sum / float64(d.n)
 	sum := float64(0)
-	d.hist.iter(func(v float64) {
+	d.hist.Iter(func(v float64) {
 		sum += math.Abs(v - mean)
 	})
 

diff.go

@@ -9,22 +9,22 @@ package tart
 // their point values.
 type Diff struct {
 	n    int64
-	hist *cBuf
+	hist *CBuf
 	sz   int64
 }
 
 func NewDiff(n int64) *Diff {
 	return &Diff{
 		n:    n,
-		hist: newCBuf(n),
+		hist: NewCBuf(n),
 		sz:   0,
 	}
 }
 
 func (d *Diff) Update(v float64) float64 {
 	d.sz++
 
-	old := d.hist.append(v)
+	old := d.hist.Append(v)
 
 	if d.sz <= d.n {
 		return 0

max.go

@@ -3,44 +3,44 @@ package tart
 // Max value of the selected period.
 type Max struct {
 	n      int64
-	hist   *cBuf
+	hist   *CBuf
 	max    float64
 	maxIdx int64
 }
 
 func NewMax(n int64) *Max {
 	return &Max{
 		n:      n,
-		hist:   newCBuf(n),
+		hist:   NewCBuf(n),
 		max:    0,
 		maxIdx: 0,
 	}
 }
 
 func (m *Max) Update(v float64) (int64, float64) {
-	m.hist.append(v)
+	m.hist.Append(v)
 
-	if m.hist.size() < m.n {
+	if m.hist.Size() < m.n {
 		return 0, 0
 	}
 
-	if m.hist.size() == m.n || m.maxIdx == m.hist.newestIndex() {
-		m.maxIdx, m.max = m.hist.max()
+	if m.hist.Size() == m.n || m.maxIdx == m.hist.NewestIndex() {
+		m.maxIdx, m.max = m.hist.Max()
 	} else if m.max <= v {
 		// conforming to TA-Lib which updates maxIdx on equality
 		m.max = v
-		m.maxIdx = m.hist.newestIndex()
+		m.maxIdx = m.hist.NewestIndex()
 	}
 
-	return m.hist.indexToSeq(m.maxIdx), m.max
+	return m.hist.IndexToSeq(m.maxIdx), m.max
 }
 
 func (m *Max) InitPeriod() int64 {
 	return m.n - 1
 }
 
 func (m *Max) Valid() bool {
-	return m.hist.size() > m.InitPeriod()
+	return m.hist.Size() > m.InitPeriod()
 }
 
 // Max value of the selected period.

min.go

@@ -3,44 +3,44 @@ package tart
 // Min value of the selected period.
 type Min struct {
 	n      int64
-	hist   *cBuf
+	hist   *CBuf
 	min    float64
 	minIdx int64
 }
 
 func NewMin(n int64) *Min {
 	return &Min{
 		n:      n,
-		hist:   newCBuf(n),
+		hist:   NewCBuf(n),
 		min:    0,
 		minIdx: 0,
 	}
 }
 
 func (m *Min) Update(v float64) (int64, float64) {
-	m.hist.append(v)
+	m.hist.Append(v)
 
-	if m.hist.size() < m.n {
+	if m.hist.Size() < m.n {
 		return 0, 0
 	}
 
-	if m.hist.size() == m.n || m.minIdx == m.hist.newestIndex() {
-		m.minIdx, m.min = m.hist.min()
+	if m.hist.Size() == m.n || m.minIdx == m.hist.NewestIndex() {
+		m.minIdx, m.min = m.hist.Min()
 	} else if m.min >= v {
 		// conforming to TA-Lib which updates minIdx on equality
 		m.min = v
-		m.minIdx = m.hist.newestIndex()
+		m.minIdx = m.hist.NewestIndex()
 	}
 
-	return m.hist.indexToSeq(m.minIdx), m.min
+	return m.hist.IndexToSeq(m.minIdx), m.min
 }
 
 func (m *Min) InitPeriod() int64 {
 	return m.n - 1
 }
 
 func (m *Min) Valid() bool {
-	return m.hist.size() > m.InitPeriod()
+	return m.hist.Size() > m.InitPeriod()
 }
 
 // Min value of the selected period.

roc.go

@@ -17,22 +17,22 @@ package tart
 //  https://www.fidelity.com/learning-center/trading-investing/technical-analysis/technical-indicator-guide/roc
 type Roc struct {
 	n    int64
-	hist *cBuf
+	hist *CBuf
 	sz   int64
 }
 
 func NewRoc(n int64) *Roc {
 	return &Roc{
 		n:    n,
-		hist: newCBuf(n),
+		hist: NewCBuf(n),
 		sz:   0,
 	}
 }
 
 func (r *Roc) Update(v float64) float64 {
 	r.sz++
 
-	old := r.hist.append(v)
+	old := r.hist.Append(v)
 
 	if r.sz <= r.n {
 		return 0