gistfile1.go

package main

import (
    "fmt"
    "os"
    "errors"
    "github.com/adsr/portmidi"
)

func main() {
    if err := run(); err != nil {
        fmt.Printf("Error: %v\n", err)
        os.Exit(1)
    }
}

func run() error {
    // Init portmidi
    if err := portmidi.Initialize(); err != nil {
        return err
    }
    defer portmidi.Terminate()

    // Get device name from argv
    if deviceName, err := getDeviceNameFromArgs(); err != nil {
        printUsage()
        return err
    } else if stream, err := getStreamByName(deviceName); err != nil {
        return err
    } else {
        // Do sysex test
        defer stream.Close()
        for j := 0; j < 128; j++ {
            sysexBytes := []byte{0xf0, 0x7f, 0x00, 0x00, 0x00, byte(j), 0xf7}
            stream.WriteSysEx(0, string(sysexBytes)) // This segfaults without the patch applied
            fmt.Printf("Sent sysex %v to device '%s'\n", sysexBytes, deviceName)
        }
    }
    return nil
}

func getDeviceNameFromArgs() (string, error) {
    if len(os.Args) < 2 {
        return "", errors.New("Missing midi_out_device argument")
    }
    return os.Args[1], nil
}

func printUsage() {
    fmt.Printf("Usage: %s <midi_out_device>\n\n", os.Args[0])
    fmt.Printf("Possible values for midi_out_device:\n")
    for i := 0; i < portmidi.CountDevices(); i++ {
        info := portmidi.GetDeviceInfo(portmidi.DeviceId(i))
        if !info.IsOutputAvailable || info.IsOpened {
            continue
        }
        fmt.Printf("    %s\n", info.Name)
    }
}

func getStreamByName(deviceName string) (*portmidi.Stream, error) {
    for i := 0; i < portmidi.CountDevices(); i++ {
        deviceId := portmidi.DeviceId(i)
        info := portmidi.GetDeviceInfo(deviceId)
        if info.Name != deviceName || !info.IsOutputAvailable || info.IsOpened {
            continue
        }
        if stream, err := portmidi.NewOutputStream(deviceId, 1024, 0); err != nil {
            return nil, err
        } else {
            return stream, nil
        }
    }
    return nil, errors.New("Device not found or already opened")
}