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// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package counter
import (
"math"
"sync"
"time"
)
// Tracker is a min/max value tracker that keeps track of its min/max values
// over a given period of time, and with a given resolution. The initial min
// and max values are math.MaxInt64 and math.MinInt64 respectively.
type Tracker struct {
mu sync.RWMutex
min, max int64 // All time min/max.
minTS, maxTS [3]*timeseries
lastUpdate time.Time
}
// NewTracker returns a new Tracker.
func NewTracker() *Tracker {
now := TimeNow()
t := &Tracker{}
t.minTS[hour] = newTimeSeries(now, time.Hour, time.Minute)
t.minTS[tenminutes] = newTimeSeries(now, 10*time.Minute, 10*time.Second)
t.minTS[minute] = newTimeSeries(now, time.Minute, time.Second)
t.maxTS[hour] = newTimeSeries(now, time.Hour, time.Minute)
t.maxTS[tenminutes] = newTimeSeries(now, 10*time.Minute, 10*time.Second)
t.maxTS[minute] = newTimeSeries(now, time.Minute, time.Second)
t.init()
return t
}
func (t *Tracker) init() {
t.min = math.MaxInt64
t.max = math.MinInt64
for _, ts := range t.minTS {
ts.set(math.MaxInt64)
}
for _, ts := range t.maxTS {
ts.set(math.MinInt64)
}
}
func (t *Tracker) advance() time.Time {
now := TimeNow()
for _, ts := range t.minTS {
ts.advanceTimeWithFill(now, math.MaxInt64)
}
for _, ts := range t.maxTS {
ts.advanceTimeWithFill(now, math.MinInt64)
}
return now
}
// LastUpdate returns the last update time of the range.
func (t *Tracker) LastUpdate() time.Time {
t.mu.RLock()
defer t.mu.RUnlock()
return t.lastUpdate
}
// Push adds a new value if it is a new minimum or maximum.
func (t *Tracker) Push(value int64) {
t.mu.Lock()
defer t.mu.Unlock()
t.lastUpdate = t.advance()
if t.min > value {
t.min = value
}
if t.max < value {
t.max = value
}
for _, ts := range t.minTS {
if ts.headValue() > value {
ts.set(value)
}
}
for _, ts := range t.maxTS {
if ts.headValue() < value {
ts.set(value)
}
}
}
// Min returns the minimum value of the tracker
func (t *Tracker) Min() int64 {
t.mu.RLock()
defer t.mu.RUnlock()
return t.min
}
// Max returns the maximum value of the tracker.
func (t *Tracker) Max() int64 {
t.mu.RLock()
defer t.mu.RUnlock()
return t.max
}
// Min1h returns the minimum value for the last hour.
func (t *Tracker) Min1h() int64 {
t.mu.Lock()
defer t.mu.Unlock()
t.advance()
return t.minTS[hour].min()
}
// Max1h returns the maximum value for the last hour.
func (t *Tracker) Max1h() int64 {
t.mu.Lock()
defer t.mu.Unlock()
t.advance()
return t.maxTS[hour].max()
}
// Min10m returns the minimum value for the last 10 minutes.
func (t *Tracker) Min10m() int64 {
t.mu.Lock()
defer t.mu.Unlock()
t.advance()
return t.minTS[tenminutes].min()
}
// Max10m returns the maximum value for the last 10 minutes.
func (t *Tracker) Max10m() int64 {
t.mu.Lock()
defer t.mu.Unlock()
t.advance()
return t.maxTS[tenminutes].max()
}
// Min1m returns the minimum value for the last 1 minute.
func (t *Tracker) Min1m() int64 {
t.mu.Lock()
defer t.mu.Unlock()
t.advance()
return t.minTS[minute].min()
}
// Max1m returns the maximum value for the last 1 minute.
func (t *Tracker) Max1m() int64 {
t.mu.Lock()
defer t.mu.Unlock()
t.advance()
return t.maxTS[minute].max()
}
// Reset resets the range to an empty state.
func (t *Tracker) Reset() {
t.mu.Lock()
defer t.mu.Unlock()
now := TimeNow()
for _, ts := range t.minTS {
ts.reset(now)
}
for _, ts := range t.maxTS {
ts.reset(now)
}
t.init()
}