feat: add OpenReader API

file.go

@@ -50,15 +50,18 @@ func Open(filePath string) (*GoFile, error) {
 	if err != nil {
 		return nil, err
 	}
-
 	_, err = f.Seek(0, io.SeekStart)
 	if err != nil {
 		return nil, err
 	}
 
+	return OpenReader(f)
+}
+
+// OpenReader opens a reader and returns a handler to the file.
+func OpenReader(f io.ReaderAt) (*GoFile, error) {
 	buf := make([]byte, maxMagicBufLen)
-	n, err := f.Read(buf)
-	_ = f.Close()
+	n, err := f.ReadAt(buf, 0)
 	if err != nil {
 		return nil, err
 	}
@@ -79,11 +82,11 @@ func Open(filePath string) (*GoFile, error) {
 		}
 		gofile.fh = pe
 	} else if fileMagicMatch(buf, machoMagic1) || fileMagicMatch(buf, machoMagic2) || fileMagicMatch(buf, machoMagic3) || fileMagicMatch(buf, machoMagic4) {
-		macho, err := openMachO(f)
+		machO, err := openMachO(f)
 		if err != nil {
 			return nil, err
 		}
-		gofile.fh = macho
+		gofile.fh = machO
 	} else {
 		return nil, ErrUnsupportedFile
 	}

file_test.go

@@ -172,9 +172,8 @@ func TestGoldFiles(t *testing.T) {
 			require.NotNil(version, "Version should not be nil")
 			assert.Equal("go"+actualVersion, version.Name, "Incorrect version for "+file)
 
-			osFile := f.GetFile()
-			require.NotNil(osFile, "File should not be nil")
-			assert.IsType(&os.File{}, osFile, "File should be of type *os.File")
+			reader := f.GetReader()
+			require.NotNil(reader, "File should not be nil")
 
 			switch f.GetParsedFile().(type) {
 			case *elf.File: