Add MusicXML to frequencies CSV program

1 files changed, 188 insertions, 0 deletions

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.")
+
+}