commit 6a63bf0e0d1effa9270015f0c8a3330f62d158a9
Author: David Högborg <david.hogborg@greatbeyond.se>
Date:   Wed Jul 15 01:09:43 2015 +0200

    initial source

diff --git a/gopow/gopow.go b/gopow/gopow.go
new file mode 100644
index 0000000..2a1a24c
--- /dev/null
+++ b/gopow/gopow.go
@@ -0,0 +1,100 @@
+package gopow
+
+import (
+	"fmt"
+	"image"
+	"image/png"
+	"os"
+
+	log "github.com/Sirupsen/logrus"
+	"github.com/codegangsta/cli"
+)
+
+type RunConfig struct {
+	InputFile  string
+	OutputFile string
+	Format     string
+	Downsample int
+}
+
+type GoPow struct {
+	config *RunConfig
+	image  *image.RGBA
+}
+
+func NewGoPow(c *cli.Context) (*GoPow, error) {
+
+	config := &RunConfig{
+		InputFile:  c.String("input"),
+		OutputFile: c.String("output"),
+		Format:     c.String("format"),
+		Downsample: c.Int("downsample"),
+	}
+
+	if config.InputFile == "" {
+		return nil, fmt.Errorf("missing input file")
+	}
+
+	if config.Format == "" {
+		config.Format = "png"
+	}
+
+	if config.OutputFile == "" {
+		config.OutputFile = config.InputFile + "." + config.Format
+	}
+
+	log.WithFields(log.Fields{
+		"input": config.InputFile,
+	}).Info("GoPow init")
+	log.WithFields(log.Fields{
+		"output": config.OutputFile,
+	}).Info("GoPow init")
+	log.WithFields(log.Fields{
+		"format": config.Format,
+	}).Info("GoPow init")
+
+	g := &GoPow{
+		config: config,
+	}
+
+	return g, nil
+}
+
+func (g *GoPow) Render() error {
+
+	log.Debug("staring render")
+
+	table, err := NewTable(g.config.InputFile)
+	if err != nil {
+		return err
+	}
+
+	g.image = table.Image()
+
+	for y, row := range table.Rows {
+		for x, _ := range row.Samples {
+			g.image.Set(x, y, table.ColorAt(x, y))
+		}
+	}
+
+	return nil
+}
+
+func (g *GoPow) Write() error {
+
+	log.WithFields(log.Fields{
+		"file": g.config.OutputFile,
+	}).Debug("staring output write")
+
+	out, err := os.Create(g.config.OutputFile)
+	if err != nil {
+		return err
+	}
+
+	err = png.Encode(out, g.image)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
diff --git a/gopow/line.go b/gopow/line.go
new file mode 100644
index 0000000..939bdbc
--- /dev/null
+++ b/gopow/line.go
@@ -0,0 +1,154 @@
+package gopow
+
+import (
+	"strconv"
+	"strings"
+	"time"
+
+	log "github.com/Sirupsen/logrus"
+)
+
+type LineComplex struct {
+	Time *time.Time
+	Hash string // a unique hash for this line in time
+
+	HzLow       float64
+	HzHigh      float64
+	HzStep      float64
+	SampleCount int
+
+	Samples []float64
+}
+
+type LineSort []*LineComplex
+
+func (a LineSort) Len() int {
+	return len(a)
+}
+
+func (a LineSort) Swap(i, j int) {
+	a[i], a[j] = a[j], a[i]
+}
+
+func (a LineSort) Less(i, j int) bool {
+	if a[i].Time == nil {
+		return false
+	}
+
+	if a[j].Time == nil {
+		return true
+	}
+
+	return a[i].Time.Unix() < a[j].Time.Unix()
+}
+
+func NewLineComplex(cells []string) *LineComplex {
+
+	// bail early if there is something wrong with the line
+	if len(cells) < 7 {
+		return &LineComplex{}
+	}
+
+	date := cells[0]
+	clock := cells[1]
+
+	const format = "2006-01-02 15:04:05"
+	datetime, err := time.Parse(format, date+clock)
+	if err != nil {
+		log.WithFields(log.Fields{
+			"error":  err,
+			"string": date + clock,
+		}).Fatal("date parsing failure")
+	}
+
+	hzLow, _ := strconv.ParseFloat(cells[2], 64)
+	hzHigh, _ := strconv.ParseFloat(cells[3], 64)
+	hzStep, _ := strconv.ParseFloat(cells[3], 64)
+	sc, _ := strconv.ParseInt(cells[4], 10, 64)
+
+	samples := []float64{}
+	for _, s := range cells[6:] {
+		sf64, err := strconv.ParseFloat(strings.Trim(s, " "), 64)
+		if err != nil {
+			samples = append(samples, 0)
+		} else {
+			samples = append(samples, sf64)
+		}
+	}
+
+	// downsampl := 1
+	// // the mean of 10 hz makes up a pixel
+	// samplesFilter := []float64{}
+	// for i := 0; i < len(samples); i = i + downsampl {
+
+	// 	mean := 0.0
+	// 	samps := 0
+
+	// 	for ii := 0; ii < downsampl; ii++ {
+	// 		if len(samples)-1 > i+ii {
+	// 			samps++
+	// 			mean += samples[i+ii]
+	// 		}
+	// 	}
+
+	// 	mean = mean / float64(samps)
+
+	// 	samplesFilter = append(samplesFilter, mean)
+	// }
+
+	return &LineComplex{
+		Time:        &datetime,
+		Hash:        cells[0] + cells[1],
+		HzLow:       hzLow,
+		HzHigh:      hzHigh,
+		HzStep:      hzStep,
+		SampleCount: int(sc),
+
+		Samples: samples, // the rest of the cells end up as samples
+	}
+}
+
+func (l *LineComplex) AddSamples(line *LineComplex) {
+
+	if line.HzHigh > l.HzHigh {
+		l.HzHigh = line.HzHigh
+	}
+
+	if line.HzLow < l.HzLow {
+		l.HzLow = line.HzLow
+	}
+
+	if l.Samples == nil {
+		l.Samples = []float64{}
+	}
+
+	l.Samples = append(l.Samples, line.Samples...)
+
+}
+
+func (l *LineComplex) HighSample() float64 {
+
+	high := float64(-99999)
+	for _, sample := range l.Samples {
+		if sample > high {
+			high = sample
+		}
+	}
+
+	return high
+}
+
+func (l *LineComplex) LowSample() float64 {
+	low := float64(99999)
+	for _, sample := range l.Samples {
+		if sample < low {
+			low = sample
+		}
+	}
+
+	return low
+}
+
+func (l *LineComplex) Sample(x int) float64 {
+	return l.Samples[x]
+}
diff --git a/gopow/table.go b/gopow/table.go
new file mode 100644
index 0000000..93ef038
--- /dev/null
+++ b/gopow/table.go
@@ -0,0 +1,177 @@
+package gopow
+
+import (
+	"image"
+	"image/color"
+	"io/ioutil"
+	"sort"
+	"strings"
+	"time"
+
+	log "github.com/Sirupsen/logrus"
+	"github.com/dustin/go-humanize"
+	"github.com/lucasb-eyer/go-colorful"
+)
+
+type TableComplex struct {
+	File string // our input file
+
+	Rows []*LineComplex
+
+	Min float64 // minimum power value, used for color rendering
+	Max float64 // maximum dito
+
+	FreqStart float64
+	FreqEnd   float64
+
+	Bins         int // horizontal slots, columns, bandwidth
+	Integrations int // vertical slots, rows
+
+	TimeStart time.Time // real time
+	TimeEnd   time.Time
+}
+
+func NewTable(file string) (*TableComplex, error) {
+
+	log.Debug("creating table")
+
+	t := &TableComplex{}
+
+	err := t.Load(file)
+	if err != nil {
+		return nil, err
+	}
+
+	return t, nil
+}
+
+func (t *TableComplex) Load(file string) error {
+
+	log.Debug("loading table")
+
+	t.File = file
+
+	buff, err := ioutil.ReadFile(t.File)
+	if err != nil {
+		return err
+	}
+
+	log.WithFields(log.Fields{
+		"bytes": len(buff),
+		"size":  humanize.Bytes(uint64(len(buff))),
+	}).Debug("file loaded")
+
+	t.Rows = t.parseBuffer(buff)
+
+	return nil
+}
+
+func (t *TableComplex) parseBuffer(filebuffer []byte) []*LineComplex {
+
+	t.Max = float64(-99999999)
+	t.Min = float64(99999999)
+
+	block := string(filebuffer)
+	lines := strings.Split(block, "\n")
+
+	table := map[string][]*LineComplex{}
+
+	for _, l := range lines {
+
+		cells := strings.Split(l, ",")
+		line := NewLineComplex(cells)
+
+		if table[line.Hash] == nil {
+			table[line.Hash] = []*LineComplex{}
+		}
+
+		table[line.Hash] = append(table[line.Hash], line)
+	}
+
+	rows := []*LineComplex{}
+
+	// loop over hash keys with lines
+	for _, lines := range table {
+
+		row := t.IntegrateLines(lines)
+
+		if row != nil {
+
+			rows = append(rows, row)
+
+			if t.Min > row.LowSample() {
+				t.Min = row.LowSample()
+			}
+
+			if t.Max < row.HighSample() {
+				t.Max = row.HighSample()
+			}
+		}
+	}
+
+	sort.Sort(LineSort(rows))
+
+	log.WithFields(log.Fields{
+		"pMax": t.Max,
+		"pMin": t.Min,
+	}).Debug("integrated lines")
+
+	t.Integrations = len(rows)
+
+	if t.Integrations > 0 {
+		t.Bins = len(rows[0].Samples)
+	} else {
+		log.Fatal("no samples found")
+	}
+
+	log.WithFields(log.Fields{
+		"bins":         t.Bins,
+		"integrations": t.Integrations,
+	}).Debug("parsed table")
+
+	return rows
+}
+
+func (t *TableComplex) Image() *image.RGBA {
+
+	log.WithFields(log.Fields{
+		"width":  t.Bins,
+		"height": t.Integrations,
+	}).Debug("create image")
+
+	return image.NewRGBA(image.Rect(0, 0, int(t.Bins), int(t.Integrations)))
+}
+
+func (t *TableComplex) IntegrateLines(lines []*LineComplex) *LineComplex {
+
+	if len(lines) == 0 {
+		return nil
+	}
+
+	masterline := lines[0]
+	for i, l := range lines {
+		if i > 0 {
+			masterline.AddSamples(l)
+		}
+
+	}
+
+	return masterline
+}
+
+func (t *TableComplex) ColorAt(x, y int) color.Color {
+
+	cell := t.Rows[y].Sample(x)
+
+	hue_start := 236.0
+	hue_end := 0.0
+
+	span := (t.Min - t.Max) * -1
+	h_per_deg := (hue_start - hue_end) / span
+	pow_normalized := cell - t.Min
+	pow_degrees := pow_normalized * h_per_deg
+	hue := hue_start - pow_degrees
+
+	return colorful.Hsv(hue, 1, 0.8)
+
+}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..16bdfb1
--- /dev/null
+++ b/main.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"./gopow"
+	log "github.com/Sirupsen/logrus"
+	"github.com/codegangsta/cli"
+	"os"
+)
+
+func main() {
+
+	app := cli.NewApp()
+	app.Name = "RTL GoPow"
+	app.Usage = "Render a rtl_power CSV output as waterfall image"
+	app.Version = "0.0.1"
+	app.Author = "github.com/dhogborg"
+	app.Email = "d@hogborg.se"
+
+	app.Action = func(c *cli.Context) {
+
+		if c.Bool("verbose") == true {
+			log.SetLevel(log.DebugLevel)
+		} else {
+			log.SetLevel(log.InfoLevel)
+		}
+
+		pow, err := gopow.NewGoPow(c)
+		if err != nil {
+			log.WithFields(log.Fields{
+				"error": err.Error(),
+			}).Fatal("load failed")
+			return
+		}
+
+		err = pow.Render()
+		if err != nil {
+			log.WithFields(log.Fields{
+				"error": err.Error(),
+			}).Fatal("render failed")
+			return
+		}
+
+		err = pow.Write()
+		if err != nil {
+			log.WithFields(log.Fields{
+				"error": err.Error(),
+			}).Fatal("write failed")
+			return
+		}
+
+	}
+
+	app.Flags = []cli.Flag{
+		cli.StringFlag{
+			Name:  "input,i",
+			Value: "",
+			Usage: "CSV input file generated by rtl_power",
+		},
+		cli.StringFlag{
+			Name:  "output,o",
+			Value: "",
+			Usage: "Output file, default same as input file with new extension",
+		},
+		cli.StringFlag{
+			Name:  "format,f",
+			Value: "png",
+			Usage: "Output file format, default png",
+		},
+		cli.IntFlag{
+			Name:  "downsample,d",
+			Value: 10,
+			Usage: "Downsample bandwidth by factor. Use if sampled bandwidth is unmanagable wide. 1 is 1:1, 10 is 1:10 and so on.",
+		},
+		cli.BoolFlag{
+			Name:  "verbose",
+			Usage: "Enable more verbose output",
+		},
+	}
+
+	app.Run(os.Args)
+}