Add QLab OSC client library with TCP/SLIP transport

2026-02-11 21:58:30 -08:00
parent dd54bb9797
commit 366f1714a0
2 changed files with 552 additions and 0 deletions
--- a/lib/qlab/osc.go
+++ b/lib/qlab/osc.go
@@ -0,0 +1,152 @@
+package qlab
+
+import (
+	"encoding/binary"
+	"fmt"
+	"math"
+)
+
+func oscPad(n int) int {
+	return (4 - n%4) % 4
+}
+
+func buildOSC(addr string, args ...any) []byte {
+	var buf []byte
+
+	buf = append(buf, []byte(addr)...)
+	buf = append(buf, 0)
+	for range oscPad(len(addr) + 1) {
+		buf = append(buf, 0)
+	}
+
+	typetag := ","
+	for _, arg := range args {
+		switch arg.(type) {
+		case int32:
+			typetag += "i"
+		case float32:
+			typetag += "f"
+		case string:
+			typetag += "s"
+		case []byte:
+			typetag += "b"
+		case int64:
+			typetag += "h"
+		case float64:
+			typetag += "d"
+		}
+	}
+	buf = append(buf, []byte(typetag)...)
+	buf = append(buf, 0)
+	for range oscPad(len(typetag) + 1) {
+		buf = append(buf, 0)
+	}
+
+	for _, arg := range args {
+		switch v := arg.(type) {
+		case int32:
+			buf = binary.BigEndian.AppendUint32(buf, uint32(v))
+		case float32:
+			buf = binary.BigEndian.AppendUint32(buf, math.Float32bits(v))
+		case string:
+			buf = append(buf, []byte(v)...)
+			buf = append(buf, 0)
+			for range oscPad(len(v) + 1) {
+				buf = append(buf, 0)
+			}
+		case []byte:
+			buf = binary.BigEndian.AppendUint32(buf, uint32(len(v)))
+			buf = append(buf, v...)
+			for range oscPad(len(v)) {
+				buf = append(buf, 0)
+			}
+		case int64:
+			buf = binary.BigEndian.AppendUint64(buf, uint64(v))
+		case float64:
+			buf = binary.BigEndian.AppendUint64(buf, math.Float64bits(v))
+		}
+	}
+
+	return buf
+}
+
+func parseOSC(data []byte) (addr string, args []any, err error) {
+	if len(data) < 4 {
+		return "", nil, fmt.Errorf("osc: message too short")
+	}
+
+	end := 0
+	for end < len(data) && data[end] != 0 {
+		end++
+	}
+	addr = string(data[:end])
+	pos := end + 1 + oscPad(end+1)
+
+	if pos >= len(data) || data[pos] != ',' {
+		return addr, nil, nil
+	}
+
+	ttEnd := pos
+	for ttEnd < len(data) && data[ttEnd] != 0 {
+		ttEnd++
+	}
+	typetag := string(data[pos+1 : ttEnd])
+	pos = ttEnd + 1 + oscPad(ttEnd-pos)
+
+	for _, t := range typetag {
+		switch t {
+		case 'i':
+			if pos+4 > len(data) {
+				return addr, args, fmt.Errorf("osc: truncated int32")
+			}
+			args = append(args, int32(binary.BigEndian.Uint32(data[pos:])))
+			pos += 4
+		case 'f':
+			if pos+4 > len(data) {
+				return addr, args, fmt.Errorf("osc: truncated float32")
+			}
+			args = append(args, math.Float32frombits(binary.BigEndian.Uint32(data[pos:])))
+			pos += 4
+		case 's':
+			end := pos
+			for end < len(data) && data[end] != 0 {
+				end++
+			}
+			args = append(args, string(data[pos:end]))
+			pos = end + 1 + oscPad(end-pos+1)
+		case 'b':
+			if pos+4 > len(data) {
+				return addr, args, fmt.Errorf("osc: truncated blob size")
+			}
+			size := int(binary.BigEndian.Uint32(data[pos:]))
+			pos += 4
+			if pos+size > len(data) {
+				return addr, args, fmt.Errorf("osc: truncated blob")
+			}
+			b := make([]byte, size)
+			copy(b, data[pos:pos+size])
+			args = append(args, b)
+			pos += size + oscPad(size)
+		case 'h':
+			if pos+8 > len(data) {
+				return addr, args, fmt.Errorf("osc: truncated int64")
+			}
+			args = append(args, int64(binary.BigEndian.Uint64(data[pos:])))
+			pos += 8
+		case 'd':
+			if pos+8 > len(data) {
+				return addr, args, fmt.Errorf("osc: truncated float64")
+			}
+			args = append(args, math.Float64frombits(binary.BigEndian.Uint64(data[pos:])))
+			pos += 8
+		case 'T':
+			args = append(args, true)
+		case 'F':
+			args = append(args, false)
+		case 'N':
+			args = append(args, nil)
+		}
+	}
+
+	return addr, args, nil
+}