diff data/fileio/TextTest.h @ 1855:db489a1ece9b

Pull out text-document check; it's useful elsewhere

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/data/fileio/TextTest.h	Mon May 11 17:27:18 2020 +0100
@@ -0,0 +1,41 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef SV_TEXT_TEST_H
+#define SV_TEXT_TEST_H
+
+#include "data/fileio/FileSource.h"
+
+class TextTest
+{
+public:
+    /**
+     * Return true if the source appears to point to a text format of
+     * some kind (could be CSV, XML, RDF/Turtle etc).
+     *
+     * We apply two tests and report success if either succeeds:
+     *
+     * 1. The first few hundred bytes (where present) of the document
+     *    are valid UTF-8
+     *
+     * 2. The document starts with the text "<?xml" when opened using
+     *    QXmlInputSource (which guesses its text encoding)
+     *
+     * So we only accept non-UTF-8 encodings where they also happen to
+     * be XML documents.
+     */
+    static bool isApparentTextDocument(FileSource);
+};
+
+#endif