Merged in BitrateCalculatorPackage (pull request #7)

BitrateCalculatorPackage

Approved-by: Alan Noble <anoble@gmail.com>

bitrate/BitrateCalculator.go

@@ -0,0 +1,72 @@
+/*
+NAME
+  BitrateCalculator.go - is a simple struct with methods to allow for easy
+	calculation of bitrate.
+
+DESCRIPTION
+  See Readme.md
+
+AUTHOR
+  Saxon Nelson-Milton <saxon.milton@gmail.com>
+
+LICENSE
+  BitrateCalculator.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)
+
+  It is free software: you can redistribute it and/or modify them
+  under the terms of the GNU General Public License as published by the
+  Free Software Foundation, either version 3 of the License, or (at your
+  option) any later version.
+
+  It is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with revid in gpl.txt.  If not, see [GNU licenses](http://www.gnu.org/licenses).
+*/
+
+package bitrate
+
+import (
+	"fmt"
+	"time"
+)
+
+// BitrateCalculator provides fields and methods to allow calculation of bitrate
+type BitrateCalculator struct {
+	outputDelay     int // sec
+	now             time.Time
+	prev            time.Time
+	startedBefore   bool
+	elapsedTime     time.Duration
+	lastDisplayTime time.Time
+}
+
+// Place this at the start of the code segment that you would like to time
+func (bc *BitrateCalculator) Start(outputDelay int) {
+	if outputDelay >= 0 {
+		bc.outputDelay = outputDelay
+	} else {
+		bc.outputDelay = 0
+	}
+	bc.prev = time.Now()
+	if !bc.startedBefore {
+		bc.startedBefore = true
+		bc.elapsedTime = time.Duration(0)
+		bc.lastDisplayTime = time.Now()
+	}
+}
+
+// Place this at the end of the code segment that you would like to time
+func (bc *BitrateCalculator) Stop(noOfKB float64) (bitrate int64) {
+	bc.now = time.Now()
+	deltaTime := bc.now.Sub(bc.prev)
+	if bc.now.Sub(bc.lastDisplayTime) > time.Duration(bc.outputDelay)*time.Second {
+		bitrate = int64(noOfKB / float64(deltaTime/1e9))
+		fmt.Printf("Bitrate: %d kbps\n", bitrate)
+		bc.elapsedTime = time.Duration(0)
+		bc.lastDisplayTime = bc.now
+	}
+	return
+}

bitrate/BitrateCalculator_test.go

@@ -0,0 +1,77 @@
+/*
+NAME
+  BitrateCalculator_test.go - is a file that may be used to test the
+	BitrateCalculator.go file using the golang testing utilities
+
+DESCRIPTION
+  See Readme.md
+
+AUTHOR
+  Saxon Nelson-Milton <saxon.milton@gmail.com>
+
+LICENSE
+  BitrateCalculator_test.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)
+
+  It is free software: you can redistribute it and/or modify them
+  under the terms of the GNU General Public License as published by the
+  Free Software Foundation, either version 3 of the License, or (at your
+  option) any later version.
+
+  It is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with revid in gpl.txt.  If not, see [GNU licenses](http://www.gnu.org/licenses).
+*/
+
+package bitrate
+
+import (
+	"testing"
+	"time"
+)
+
+// Some consts used over duration of testing
+const (
+	bitrateDelay1 = 0 // s
+	bitrateDelay2 = 5 // s
+	amountOfData  = 100000.0
+	testTime      = 2500.0 // ms
+)
+
+// This will be the BitrateCalculator object we use over testing
+var bitrateCalc BitrateCalculator
+
+// Simple test to check that the calculator can calc bitrate over a given
+// duration of time
+func Test1(t *testing.T) {
+	bitrateCalc = BitrateCalculator{}
+	bitrateCalc.Start(bitrateDelay1)
+	time.Sleep(testTime * time.Millisecond)
+	currentBitrate := int64(bitrateCalc.Stop(amountOfData))
+	actualBitrate := int64(amountOfData / ((testTime * time.Millisecond) / 1e9))
+	if currentBitrate != actualBitrate {
+		t.Errorf("Bitrate is wrong! Calculated: %v Actual %v", currentBitrate, actualBitrate)
+	}
+}
+
+// Now let's check that the output delay feature works
+func Test2(t *testing.T) {
+	bitrateCalc = BitrateCalculator{}
+	var currentBitrate int64
+	for i := 0; i < 2; i++ {
+		bitrateCalc.Start(bitrateDelay2)
+		time.Sleep(testTime * time.Millisecond)
+		currentBitrate = int64(bitrateCalc.Stop(amountOfData))
+		if i == 0 && currentBitrate != 0 {
+			t.Errorf("The bitrate calc did not delay outputting!")
+		}
+		time.Sleep(6000 * time.Millisecond)
+	}
+	actualBitrate := int64(amountOfData / ((testTime * time.Millisecond) / 1e9))
+	if currentBitrate != actualBitrate {
+		t.Errorf("Bitrate is wrong! Calculated: %v Actual %v", currentBitrate, actualBitrate)
+	}
+}