1 files changed, 126 insertions, 0 deletions

diff --git a/src/tag/TagString.cxx b/src/tag/TagString.cxx
new file mode 100644
index 000000000..3e8d8c1b0
--- /dev/null
+++ b/src/tag/TagString.cxx
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "TagString.hxx"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+/**
+ * Replace invalid sequences with the question mark.
+ */
+static char *
+patch_utf8(const char *src, size_t length, const gchar *end)
+{
+	/* duplicate the string, and replace invalid bytes in that
+	   buffer */
+	char *dest = g_strdup(src);
+
+	do {
+		dest[end - src] = '?';
+	} while (!g_utf8_validate(end + 1, (src + length) - (end + 1), &end));
+
+	return dest;
+}
+
+static char *
+fix_utf8(const char *str, size_t length)
+{
+	const gchar *end;
+	char *temp;
+	gsize written;
+
+	assert(str != nullptr);
+
+	/* check if the string is already valid UTF-8 */
+	if (g_utf8_validate(str, length, &end))
+		return nullptr;
+
+	/* no, it's not - try to import it from ISO-Latin-1 */
+	temp = g_convert(str, length, "utf-8", "iso-8859-1",
+			 nullptr, &written, nullptr);
+	if (temp != nullptr)
+		/* success! */
+		return temp;
+
+	/* no, still broken - there's no medication, just patch
+	   invalid sequences */
+	return patch_utf8(str, length, end);
+}
+
+static bool
+char_is_non_printable(unsigned char ch)
+{
+	return ch < 0x20;
+}
+
+static const char *
+find_non_printable(const char *p, size_t length)
+{
+	for (size_t i = 0; i < length; ++i)
+		if (char_is_non_printable(p[i]))
+			return p + i;
+
+	return nullptr;
+}
+
+/**
+ * Clears all non-printable characters, convert them to space.
+ * Returns nullptr if nothing needs to be cleared.
+ */
+static char *
+clear_non_printable(const char *p, size_t length)
+{
+	const char *first = find_non_printable(p, length);
+	char *dest;
+
+	if (first == nullptr)
+		return nullptr;
+
+	dest = g_strndup(p, length);
+
+	for (size_t i = first - p; i < length; ++i)
+		if (char_is_non_printable(dest[i]))
+			dest[i] = ' ';
+
+	return dest;
+}
+
+char *
+FixTagString(const char *p, size_t length)
+{
+	char *utf8, *cleared;
+
+	utf8 = fix_utf8(p, length);
+	if (utf8 != nullptr) {
+		p = utf8;
+		length = strlen(p);
+	}
+
+	cleared = clear_non_printable(p, length);
+	if (cleared == nullptr)
+		cleared = utf8;
+	else
+		g_free(utf8);
+
+	return cleared;
+}