Adding upstream version 2.52.6.

Signed-off-by: Daniel Baumann <daniel@debian.org>

internal/go-ole/utility.go

@@ -0,0 +1,101 @@
+package ole
+
+import (
+	"unicode/utf16"
+	"unsafe"
+)
+
+// ClassIDFrom retrieves class ID whether given is program ID or application string.
+//
+// Helper that provides check against both Class ID from Program ID and Class ID from string. It is
+// faster, if you know which you are using, to use the individual functions, but this will check
+// against available functions for you.
+func ClassIDFrom(programID string) (classID *GUID, err error) {
+	classID, err = CLSIDFromProgID(programID)
+	if err != nil {
+		classID, err = CLSIDFromString(programID)
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+// BytePtrToString converts byte pointer to a Go string.
+func BytePtrToString(p *byte) string {
+	a := (*[10000]uint8)(unsafe.Pointer(p))
+	i := 0
+	for a[i] != 0 {
+		i++
+	}
+	return string(a[:i])
+}
+
+// UTF16PtrToString is alias for LpOleStrToString.
+//
+// Kept for compatibility reasons.
+func UTF16PtrToString(p *uint16) string {
+	return LpOleStrToString(p)
+}
+
+// LpOleStrToString converts COM Unicode to Go string.
+func LpOleStrToString(p *uint16) string {
+	if p == nil {
+		return ""
+	}
+
+	length := lpOleStrLen(p)
+	a := make([]uint16, length)
+
+	ptr := unsafe.Pointer(p)
+
+	for i := 0; i < int(length); i++ {
+		a[i] = *(*uint16)(ptr)
+		ptr = unsafe.Pointer(uintptr(ptr) + 2)
+	}
+
+	return string(utf16.Decode(a))
+}
+
+// BstrToString converts COM binary string to Go string.
+func BstrToString(p *uint16) string {
+	if p == nil {
+		return ""
+	}
+	length := SysStringLen((*int16)(unsafe.Pointer(p)))
+	a := make([]uint16, length)
+
+	ptr := unsafe.Pointer(p)
+
+	for i := 0; i < int(length); i++ {
+		a[i] = *(*uint16)(ptr)
+		ptr = unsafe.Pointer(uintptr(ptr) + 2)
+	}
+	return string(utf16.Decode(a))
+}
+
+// lpOleStrLen returns the length of Unicode string.
+func lpOleStrLen(p *uint16) (length int64) {
+	if p == nil {
+		return 0
+	}
+
+	ptr := unsafe.Pointer(p)
+
+	for i := 0; ; i++ {
+		if 0 == *(*uint16)(ptr) {
+			length = int64(i)
+			break
+		}
+		ptr = unsafe.Pointer(uintptr(ptr) + 2)
+	}
+	return
+}
+
+// convertHresultToError converts syscall to error, if call is unsuccessful.
+func convertHresultToError(hr, r2 uintptr, ignore error) (err error) {
+	if hr != 0 {
+		err = NewError(hr)
+	}
+	return
+}