diff --git a/lib/buffer.c b/lib/buffer.c
new file mode 100644
index 0000000..ae9e955
--- /dev/null
+++ b/lib/buffer.c
@@ -0,0 +1,64 @@
+#include <comedi.h>
+
+#include <libinternal.h>
+
+int comedi_buf_resize(comedi_t *it, unsigned int subdev, unsigned int size)
+{
+	int ret;
+	comedi_bufconfig bc;
+
+	memset(&bc, 0, sizeof(bc));
+	bc.subdevice = subdev;
+	bc.size = size;
+	ret = ioctl_bufconfig(it->fd, &bc);
+	if(ret < 0) return ret;
+
+	return bc.size;
+}
+
+int comedi_buf_resize_max(comedi_t *it, unsigned int subdev, unsigned int max_size)
+{
+	int ret;
+	comedi_bufconfig bc;
+
+	memset(&bc, 0, sizeof(bc));
+	bc.subdevice = subdev;
+	bc.maximum_size = max_size;
+	ret = ioctl_bufconfig(it->fd, &bc);
+	if(ret < 0) return ret;
+
+	return bc.maximum_size;
+}
+
+int comedi_buf_size(comedi_t *it, unsigned int subdev)
+{
+	return comedi_buf_resize(it, subdev, 0);
+}
+
+int comedi_buf_contents(comedi_t *it, unsigned int subdev)
+{
+	return comedi_buf_mark_read(it, subdev, 0);
+}
+
+int comedi_buf_mark_read(comedi_t *it, unsigned int subdev, unsigned int bytes)
+{
+	int ret;
+	comedi_bufinfo bi;
+
+	memset(&bi, 0, sizeof(bi));
+	bi.bytes_read = bytes;
+	ret = ioctl_bufinfo(it->fd, &bi);
+	if(ret < 0) return ret;
+	return bi.buf_int_count - bi.buf_user_count;
+}
+
+int comedi_buf_offset(comedi_t *it, unsigned int subdev)
+{
+	int ret;
+	comedi_bufinfo bi;
+
+	memset(&bi, 0, sizeof(bi));
+	ret = ioctl_bufinfo(it->fd, &bi);
+	if(ret < 0) return ret;
+	return bi.buf_user_ptr;
+}