bring back the osc lib for go learning reasons

pkg/osc/osc.go

@@ -0,0 +1,267 @@
+package osc
+
+// TODO(jwetzell): split things up
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math"
+	"strings"
+)
+
+type OSCArg struct {
+	Type  string
+	Value any
+}
+
+type OSCMessage struct {
+	Address string
+	Args    []OSCArg
+}
+
+func stringToOSCBytes(rawString string) []byte {
+	var sb strings.Builder
+
+	sb.WriteString(rawString)
+	sb.WriteString("\u0000")
+
+	padLength := 4 - (len(sb.String()) % 4)
+	if padLength < 4 {
+		for i := 0; i < padLength; i++ {
+			sb.WriteString("\u0000")
+		}
+	}
+
+	return []byte(sb.String())
+}
+
+func integerToOSCBytes(number int32) []byte {
+	var buf bytes.Buffer
+	err := binary.Write(&buf, binary.BigEndian, number)
+	if err != nil {
+		panic(err)
+	}
+	return buf.Bytes()
+}
+
+func floatToOSCBytes(number float32) []byte {
+	var buf bytes.Buffer
+	err := binary.Write(&buf, binary.BigEndian, number)
+	if err != nil {
+		panic(err)
+	}
+	return buf.Bytes()
+}
+
+func byteArrayToOSCBytes(bytes []byte) []byte {
+	oscBytes := []byte{}
+
+	bytesSize := len(bytes)
+	oscBytes = append(oscBytes, integerToOSCBytes(int32(bytesSize))...)
+	oscBytes = append(oscBytes, bytes...)
+
+	padLength := 4 - (bytesSize % 4)
+	if padLength < 4 {
+		for i := 0; i < padLength; i++ {
+			oscBytes = append(oscBytes, 0)
+		}
+	}
+
+	return oscBytes
+}
+
+func argsToBuffer(args []OSCArg) []byte {
+	//TODO(jwetzell): add error handling
+	var argBuffers = []byte{}
+
+	for _, arg := range args {
+		switch oscType := arg.Type; oscType {
+		case "s":
+			if value, ok := arg.Value.(string); ok {
+				argBuffers = append(argBuffers, stringToOSCBytes(value)...)
+			} else {
+				fmt.Println("OSC arg had string type but non-string value.")
+			}
+		case "i":
+			if value, ok := arg.Value.(int); ok {
+				argBuffers = append(argBuffers, integerToOSCBytes(int32(value))...)
+			} else if value, ok := arg.Value.(int32); ok {
+				argBuffers = append(argBuffers, integerToOSCBytes(value)...)
+			} else {
+				fmt.Println("OSC arg had integer type but non-integer value.")
+			}
+		case "f":
+			if value, ok := arg.Value.(float32); ok {
+				argBuffers = append(argBuffers, floatToOSCBytes(float32(value))...)
+			} else if value, ok := arg.Value.(float64); ok {
+				argBuffers = append(argBuffers, floatToOSCBytes(float32(value))...)
+			} else {
+				fmt.Println("OSC arg had float type but non-float value.")
+			}
+		case "b":
+			if value, ok := arg.Value.([]byte); ok {
+				argBuffers = append(argBuffers, byteArrayToOSCBytes(value)...)
+			} else {
+				fmt.Println("OSC arg had blob type but non-blob value.")
+			}
+		default:
+			fmt.Printf("unhandled osc type: %s.\n", oscType)
+		}
+	}
+	return argBuffers
+}
+
+func ToBytes(message OSCMessage) []byte {
+	//TODO(jwetzell): add error handling
+	oscBuffer := []byte{}
+
+	oscBuffer = append(oscBuffer, stringToOSCBytes(message.Address)...)
+
+	var sb strings.Builder
+
+	sb.WriteString(",")
+
+	for _, arg := range message.Args {
+		sb.WriteString(arg.Type)
+	}
+
+	oscBuffer = append(oscBuffer, stringToOSCBytes(sb.String())...)
+	oscBuffer = append(oscBuffer, argsToBuffer(message.Args)...)
+
+	return oscBuffer
+}
+
+func readOSCString(bytes []byte) (string, []byte) {
+	//TODO(jwetzell): add error handling
+	oscString := ""
+	stringFinished := false
+	stringEndIndex := 0
+	remainingBytes := []byte{}
+
+	for index, byteIn := range bytes {
+		if !stringFinished {
+			if byteIn == 0 {
+				oscString = string(bytes[0:index])
+				stringEndIndex = index + 1
+				break
+			}
+		}
+	}
+
+	stringPadding := 4 - (stringEndIndex % 4)
+
+	if stringPadding < 4 {
+		stringEndIndex = stringEndIndex + stringPadding
+	}
+
+	remainingBytes = bytes[stringEndIndex:]
+
+	return oscString, remainingBytes
+}
+
+func readOSCInt(bytes []byte) (int32, []byte, error) {
+	if len(bytes) < 4 {
+		return 0, bytes, errors.New("int data must be at least 4 bytes large")
+	}
+	bits := binary.BigEndian.Uint32(bytes[0:4])
+	return int32(bits), bytes[4:], nil
+}
+
+func readOSCFloat(bytes []byte) (float32, []byte, error) {
+	if len(bytes) < 4 {
+		return 0, bytes, errors.New("float data must be at least 4 bytes large")
+	}
+	bits := binary.BigEndian.Uint32(bytes[0:4])
+	return math.Float32frombits(bits), bytes[4:], nil
+}
+
+func readOSCBlob(bytes []byte) ([]byte, []byte, error) {
+	blobLength, remainingBytes, err := readOSCInt(bytes)
+
+	if err != nil {
+		return []byte{}, bytes, errors.New("problem reading blob data size")
+	}
+
+	if len(remainingBytes) < int(blobLength) {
+		return []byte{}, bytes, errors.New("blob data specified a size larger than the remaining message data")
+	}
+
+	blobLengthPadding := 4 - (blobLength % 4)
+	blobEnd := 4 + blobLength
+
+	if blobLengthPadding < 4 {
+		blobEnd = blobEnd + blobLengthPadding
+	}
+	return bytes[4 : 4+blobLength], bytes[blobEnd:], nil
+}
+
+func readOSCArg(bytes []byte, oscType string) (OSCArg, []byte, error) {
+	var readArgError error
+
+	oscArg := OSCArg{}
+	oscArg.Type = oscType
+
+	remainingBytes := []byte{}
+	//TODO(jwetzell): add error handling
+	switch oscType {
+	case "s":
+		argString, bytesLeft := readOSCString(bytes)
+		oscArg.Value = argString
+		remainingBytes = bytesLeft
+	case "i":
+		argInt, bytesLeft, error := readOSCInt(bytes)
+		if error != nil {
+			readArgError = error
+		}
+		oscArg.Value = argInt
+		remainingBytes = bytesLeft
+	case "f":
+		argFloat, bytesLeft, error := readOSCFloat(bytes)
+		if error != nil {
+			readArgError = error
+		}
+		oscArg.Value = argFloat
+		remainingBytes = bytesLeft
+	case "b":
+		argBytes, bytesLeft, error := readOSCBlob(bytes)
+		if error != nil {
+			readArgError = error
+		}
+		oscArg.Value = argBytes
+		remainingBytes = bytesLeft
+	default:
+		fmt.Printf("unsupported osc type: %s\n", oscType)
+		readArgError = errors.New("unsupported osc type: " + oscType)
+	}
+	return oscArg, remainingBytes, readArgError
+}
+
+func FromBytes(bytes []byte) (OSCMessage, error) {
+	//TODO(jwetzell): add Message and Bundle support
+	address, typeAndArgBytes := readOSCString(bytes)
+
+	oscMessage := OSCMessage{
+		Address: address,
+		Args:    []OSCArg{},
+	}
+
+	typeString, argBytes := readOSCString(typeAndArgBytes)
+
+	for index, oscType := range typeString {
+		if index == 0 {
+			if oscType != ',' {
+				return OSCMessage{}, errors.New("type string is malformed")
+			}
+		} else {
+			oscArg, remainingBytes, error := readOSCArg(argBytes, string(oscType))
+			if error != nil {
+				return oscMessage, error
+			}
+			argBytes = remainingBytes
+			oscMessage.Args = append(oscMessage.Args, oscArg)
+		}
+	}
+
+	return oscMessage, nil
+}

pkg/osc/osc_test.go

@@ -0,0 +1,67 @@
+package osc
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+// TestHelloName calls greetings.Hello with a name, checking
+// for a valid return value.
+func TestOSCEncoding(t *testing.T) {
+
+	testCases := []struct {
+		description string
+		message     OSCMessage
+		expected    []byte
+	}{
+		{
+			"simple hello",
+			OSCMessage{
+				Address: "/hello",
+				Args:    []OSCArg{},
+			},
+			[]byte{47, 104, 101, 108, 108, 111, 0, 0, 44, 0, 0, 0},
+		},
+		{
+			"simple address string arg",
+			OSCMessage{
+				Address: "/hello",
+				Args: []OSCArg{
+					{
+						Type:  "s",
+						Value: "arg1",
+					},
+				},
+			},
+			[]byte{47, 104, 101, 108, 108, 111, 0, 0, 44, 115, 0, 0, 97, 114, 103, 49, 0, 0, 0, 0},
+		},
+		{
+			description: "simple address integer arg",
+			message:     OSCMessage{Address: "/hello", Args: []OSCArg{{Type: "i", Value: 35}}},
+			expected:    []byte{47, 104, 101, 108, 108, 111, 0, 0, 44, 105, 0, 0, 0, 0, 0, 35},
+		},
+		{
+			description: "simple address float arg",
+			message:     OSCMessage{Address: "/hello", Args: []OSCArg{{Type: "f", Value: 34.5}}},
+			expected:    []byte{47, 104, 101, 108, 108, 111, 0, 0, 44, 102, 0, 0, 66, 10, 0, 0},
+		},
+		{
+			description: "simple address blob arg",
+			message:     OSCMessage{Address: "/hello", Args: []OSCArg{OSCArg{Type: "b", Value: []byte{98, 108, 111, 98}}}},
+			expected:    []byte{47, 104, 101, 108, 108, 111, 0, 0, 44, 98, 0, 0, 0, 0, 0, 4, 98, 108, 111, 98},
+		},
+	}
+
+	for _, testCase := range testCases {
+
+		actual := ToBytes(testCase.message)
+
+		if !reflect.DeepEqual(actual, testCase.expected) {
+			t.Errorf("Test '%s' failed to encode properly", testCase.description)
+			fmt.Printf("expected: %v\n", testCase.expected)
+			fmt.Printf("actual: %v\n", actual)
+		}
+	}
+
+}