1 files changed, 54 insertions, 0 deletions
diff --git a/include/in_stream.h b/include/in_stream.h
new file mode 100644
index 0000000000..7bf8821394
--- /dev/null
+++ b/include/in_stream.h
@@ -0,0 +1,54 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef INCLUDE_IN_STREAM_H
+#define INCLUDE_IN_STREAM_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+struct in_stream;
+
+struct in_stream_ops {
+	/*
+	 * Read at most count characters from the input stream into the user
+	 * buffer provided.  Return the number of characters actually read
+	 * into the buffer.
+	 */
+	size_t (*read)(struct in_stream const *stream,
+		       uint8_t *buffer,
+		       size_t count);
+};
+
+struct in_stream {
+	/*
+	 * Ready will be called by the stream every time new characters are
+	 * added to the stream.  This may be called from an interrupt context
+	 * so work done by the ready callback should be minimal.  Likely this
+	 * callback will be used to call task_wake, or some similar signaling
+	 * mechanism.
+	 *
+	 * This callback is part of the user configuration of a stream, and not
+	 * a stream manipulation function (in_stream_ops).  That means that
+	 * each stream can be configured with its own ready callback.
+	 *
+	 * If no callback functionality is required ready can be specified as
+	 * NULL.
+	 */
+	void (*ready)(struct in_stream const *stream);
+
+	struct in_stream_ops const *ops;
+};
+
+/*
+ * Helper functions that call the associated stream operation and pass it the
+ * given stream.  These help prevent mistakes where one stream is passed to
+ * another stream's functions.
+ */
+size_t in_stream_read(struct in_stream const *stream,
+		      uint8_t *buffer,
+		      size_t count);
+void   in_stream_ready(struct in_stream const *stream);
+
+#endif /* INCLUDE_IN_STREAM_H */