From b190b9ca2c4c0339a1da97ac84aaa0d50ff23706 Mon Sep 17 00:00:00 2001
From: Pacien TRAN-GIRARD
Date: Sun, 13 Apr 2014 13:11:50 +0200
Subject: Add MusicXML to frequencies CSV program

---
 src/mxml2csv.go | 188 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 188 insertions(+)
 create mode 100644 src/mxml2csv.go

(limited to 'src')

diff --git a/src/mxml2csv.go b/src/mxml2csv.go
new file mode 100644
index 0000000..94ea5d0
--- /dev/null
+++ b/src/mxml2csv.go
@@ -0,0 +1,188 @@
+package main
+
+import (
+	"encoding/csv"
+	"encoding/xml"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"math"
+	"os"
+)
+
+const APP_VERSION = "0.1"
+
+var versionFlag *bool = flag.Bool("v", false, "Print the version number.")
+var inputFlag *string = flag.String("i", "", "The MusicXML file.")
+var outputFlag *string = flag.String("o", "", "The CSV file to generate.")
+var partFlag *int = flag.Int("p", 0, "The part to process.")
+
+func init() {
+	flag.Parse()
+
+	if *versionFlag {
+		fmt.Println("Version:", APP_VERSION)
+		return
+	}
+
+	if *outputFlag == "" {
+		*outputFlag = *inputFlag + ".csv"
+	}
+}
+
+/***** MusicXML structure *****/
+
+type XMLFile struct {
+	Parts []Part `xml:"part"`
+}
+
+type Part struct {
+	Measures []Measure `xml:"measure"`
+}
+
+type Measure struct {
+	Attributes Attributes  `xml:"attributes"`
+	Directions []Direction `xml:"direction"`
+	Notes      []Note      `xml:"note"`
+}
+
+type Attributes struct {
+	Divisions int `xml:"divisions"`
+}
+
+type Direction struct {
+	Sound Sound `xml:"sound"`
+}
+
+type Sound struct {
+	Tempo float64 `xml:"tempo,attr"`
+}
+
+type Note struct {
+	Pitch    Pitch `xml:"pitch"`
+	Duration int   `xml:"duration"`
+}
+
+type Pitch struct {
+	Step   string `xml:"step"`
+	Alter  int    `xml:"alter"`
+	Octave int    `xml:"octave"`
+}
+
+/***** Note conversion *****/
+const REFERENCE_PITCH float64 = 440
+
+var pitchOffset = map[string]int{
+	"C": -9,
+	"D": -7,
+	"E": -5,
+	"F": -4,
+	"G": -2,
+	"A": +0,
+	"B": +2,
+}
+
+func calcFrequency(pitch Pitch) float64 {
+	if pitch.Step == "" {
+		return 0
+	}
+	return REFERENCE_PITCH * float64(pitch.Octave-3) * math.Pow(2, float64(pitchOffset[pitch.Step]+pitch.Alter)/12)
+}
+
+/***** Division calculation *****/
+
+const DEFAULT_DIVISION = 24
+
+func readDivisions(part Part) int {
+	for _, measure := range part.Measures {
+		if measure.Attributes.Divisions != 0 {
+			return measure.Attributes.Divisions
+		}
+	}
+	return DEFAULT_DIVISION
+}
+
+/***** Tempo calculation *****/
+
+const DEFAULT_TEMPO = 120
+
+func readTempo(part Part) float64 {
+	for _, measure := range part.Measures {
+		for _, direction := range measure.Directions {
+			if direction.Sound.Tempo != 0 {
+				return direction.Sound.Tempo
+			}
+		}
+	}
+	return DEFAULT_TEMPO
+}
+
+func calcDuration(noteDuration int, divisions int, tempo float64) float64 {
+	return 60000 / tempo * float64(noteDuration) / float64(divisions)
+}
+
+/***** Main program *****/
+
+func main() {
+
+	// read and parse MusicXML file
+
+	inputFile, err := os.Open(*inputFlag)
+	if err != nil {
+		fmt.Println("Error opening MusicXML file:", err)
+		return
+	}
+	defer inputFile.Close()
+
+	data, err := ioutil.ReadAll(inputFile)
+	if err != nil {
+		fmt.Println("Error reading MusicXML file:", err)
+		return
+	}
+
+	var parsed XMLFile
+	xml.Unmarshal(data, &parsed)
+
+	fmt.Println("Parsed data:", parsed)
+
+	// create and write to CSV file
+
+	outputFile, err := os.Create(*outputFlag)
+	if err != nil {
+		fmt.Println("Error creating CSV file:", err)
+		return
+	}
+	defer outputFile.Close()
+
+	writer := csv.NewWriter(outputFile)
+	defer writer.Flush()
+
+	if *partFlag >= len(parsed.Parts) {
+		fmt.Println("Error: part", *partFlag, "does not exist.")
+		return
+	}
+	part := parsed.Parts[*partFlag]
+
+	tempo := readTempo(part)
+	fmt.Println("Tempo:", tempo)
+
+	divisions := readDivisions(part)
+	fmt.Println("Divisions:", divisions)
+
+	for _, measure := range part.Measures {
+		for _, note := range measure.Notes {
+			pitch := calcFrequency(note.Pitch)
+			duration := calcDuration(note.Duration, divisions, tempo)
+			line := []string{fmt.Sprint(pitch), fmt.Sprint(duration)}
+			fmt.Println(line)
+			err := writer.Write(line)
+			if err != nil {
+				fmt.Println("Error writing in CSV file:", err)
+				return
+			}
+		}
+	}
+
+	fmt.Println("Done.")
+
+}
-- 
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