Refactor code to remove duplication of FindStartPart.

1 files changed, 48 insertions, 0 deletions

diff --git a/File.cpp b/File.cpp
new file mode 100644
index 0000000..d36efcf
--- /dev/null
+++ b/File.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2008-2009, OctaneSnail <os@v12pwr.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <windows.h>
+#include <streams.h>
+
+#include "File.h"
+
+static int compare (const void *pos, const void *part)
+{
+	if (*((LONGLONG *) pos) < ((FilePart *) part)->in_file_offset)
+		return -1;
+
+	if (*((LONGLONG *) pos) >= ((FilePart *) part)->in_file_offset + ((FilePart *) part)->size)
+		return 1;
+
+	return 0;
+}
+
+int File::FindStartPart (LONGLONG position)
+{
+	if (position > size)
+		return -1;
+
+	// Check if the previous lookup up still matches.
+	if (m_prev_part && !compare (&position, m_prev_part))
+		return (int) (m_prev_part - array);
+
+	m_prev_part = (FilePart *) bsearch (&position, array, parts, sizeof (FilePart), compare);
+
+	if (!m_prev_part)
+		return -1;
+
+	return (int) (m_prev_part - array);
+}