Make log decoding build on non-Windows CI

internal/app/vrc_log.go

@@ -9,9 +9,8 @@ import (
 	"path/filepath"
 	"regexp"
 	"strings"
-	"syscall"
 	"time"
-	"unsafe"
+	"unicode/utf16"
 )
 
 var (
@@ -315,14 +314,14 @@ func decodeVRChatLog(b []byte) string {
 			for i := 2; i+1 < len(b); i += 2 {
 				u16 = append(u16, uint16(b[i])|uint16(b[i+1])<<8)
 			}
-			return strings.TrimPrefix(fixMojibake(syscall.UTF16ToString(u16)), "\ufeff")
+			return strings.TrimPrefix(fixMojibake(utf16ToString(u16)), "\ufeff")
 		}
 		if b[0] == 0xfe && b[1] == 0xff {
 			u16 := make([]uint16, 0, (len(b)-2)/2)
 			for i := 2; i+1 < len(b); i += 2 {
 				u16 = append(u16, uint16(b[i+1])|uint16(b[i])<<8)
 			}
-			return strings.TrimPrefix(fixMojibake(syscall.UTF16ToString(u16)), "\ufeff")
+			return strings.TrimPrefix(fixMojibake(utf16ToString(u16)), "\ufeff")
 		}
 	}
 	lines := bytes.Split(b, []byte{'\n'})
@@ -377,6 +376,16 @@ func tryRepairShiftJISMojibake(s string) string {
 	return ""
 }
 
+func utf16ToString(u16 []uint16) string {
+	for i, r := range u16 {
+		if r == 0 {
+			u16 = u16[:i]
+			break
+		}
+	}
+	return string(utf16.Decode(u16))
+}
+
 func scoreReadable(s string) int {
 	if s == "" {
 		return -1
@@ -401,35 +410,6 @@ func scoreReadable(s string) int {
 	return score
 }
 
-func decodeWithCodePage(b []byte, codePage uint32) string {
-	if len(b) == 0 {
-		return ""
-	}
-	kernel32 := syscall.NewLazyDLL("kernel32.dll")
-	multiByteToWideChar := kernel32.NewProc("MultiByteToWideChar")
-	n, _, _ := multiByteToWideChar.Call(
-		uintptr(codePage),
-		0,
-		uintptr(unsafe.Pointer(&b[0])),
-		uintptr(len(b)),
-		0,
-		0,
-	)
-	if n == 0 {
-		return ""
-	}
-	buf := make([]uint16, n)
-	multiByteToWideChar.Call(
-		uintptr(codePage),
-		0,
-		uintptr(unsafe.Pointer(&b[0])),
-		uintptr(len(b)),
-		uintptr(unsafe.Pointer(&buf[0])),
-		uintptr(len(buf)),
-	)
-	return syscall.UTF16ToString(buf)
-}
-
 func updateWorldState(state *vrcLogState, line string) (bool, string) {
 	worldID := ""
 	instanceID := ""