1 files changed, 127 insertions, 0 deletions
diff --git a/src/base/ringbuffer.cpp b/src/base/ringbuffer.cpp
new file mode 100644
index 00000000..7adcd332
--- /dev/null
+++ b/src/base/ringbuffer.cpp
@@ -0,0 +1,127 @@
+/*
+ * UltraStar Deluxe - Karaoke Game
+ *
+ * UltraStar Deluxe is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ */
+
+#include "ringbuffer.hpp"
+#include <stdlib.h>
+#include <string.h>
+
+namespace usdx
+{
+
+	RingBuffer::RingBuffer(int size)
+	{
+		buffer_size = size;
+
+		ring_buffer = (char*)malloc(size);
+		if (ring_buffer == NULL)
+			throw "No memory";
+	}
+
+	RingBuffer::~RingBuffer()
+	{
+		free(ring_buffer);
+	}
+
+	int RingBuffer::read(char *buffer, int count)
+	{
+		// check if there is something to do
+		if (count <= 0)
+			return count;
+
+		// adjust output count
+		if (count > buffer_count)
+		{
+			//DebugWriteln('Read too much: ' + inttostr(count) +',count:'+ inttostr(BufferCount) + '/size:' + inttostr(BufferSize));
+			count = buffer_count;
+		}
+
+		// copy data to output buffer
+
+		// first step: copy from the area between the read-position and the end of the buffer
+		int part_count = (count < buffer_size - read_pos) ? count : (buffer_size - read_pos);
+		memcpy(buffer, ring_buffer + read_pos, part_count);
+
+		// second step: if we need more data, copy from the beginning of the buffer
+		if (part_count < count)
+			memcpy(buffer + part_count, ring_buffer, count - part_count);
+
+		// mark the copied part of the buffer as free
+		buffer_count = buffer_count - count;
+		read_pos = (read_pos + count) % buffer_size;
+
+		return count;
+	}
+
+	int RingBuffer::write(char *buffer, int count)
+	{
+		// check for a reasonable request
+		if (count <= 0)
+			return count;
+
+		// skip input data if the input buffer is bigger than the ring-buffer
+		if (count > buffer_size)
+		{
+			//DebugWriteln('Write skip data:' + inttostr(count) +',count:'+ inttostr(BufferCount) + '/size:' + inttostr(BufferSize));
+			buffer += count - buffer_size;
+			count = buffer_size;
+		}
+
+		// first step: copy to the area between the write-position and the end of the buffer
+		int part_count = (count < buffer_size - write_pos) ? count : (buffer_size - write_pos);
+		memcpy(ring_buffer + write_pos, buffer, part_count);
+
+		// second step: copy data to front of buffer
+		if (part_count < count)
+			memcpy(ring_buffer, buffer + part_count, count - part_count);
+
+		// update info
+		buffer_count = (buffer_count + count < buffer_size) ? (buffer_count + count) : buffer_size;
+		write_pos = (write_pos + count) % buffer_size;
+
+		// if the buffer is full, we have to reposition the read-position
+		if (buffer_count == buffer_size)
+			read_pos = write_pos;
+
+		return count;
+	}
+
+	int RingBuffer::get_available()
+	{
+		return buffer_count;
+	}
+
+	int RingBuffer::get_size()
+	{
+		return buffer_size;
+	}
+
+	void RingBuffer::flush()
+	{
+		read_pos = 0;
+		write_pos = 0;
+		buffer_count = 0;
+	}
+};