From 00f7e3a2c957f387745dbd4ed3cf7834e5006513 Mon Sep 17 00:00:00 2001
From: Tilman Sauerbeck <tilman@code-monkey.de>
Date: Sat, 28 Dec 2019 23:11:09 +0100
Subject: [PATCH] common: Add Rust glue for the ringbuf module.

For now this only allows us to access a ringbuffer from Rust
after it has been defined in C code.
---
 SConscript.libcommon  |  1 +
 src/common/lib.rs     |  1 +
 src/common/ringbuf.rs | 50 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+)
 create mode 100644 src/common/ringbuf.rs

diff --git a/SConscript.libcommon b/SConscript.libcommon
index e1d378c..e52b43a 100644
--- a/SConscript.libcommon
+++ b/SConscript.libcommon
@@ -13,6 +13,7 @@ source_files_rs = [
     'src/common/uart.rs',
     'src/common/watchdog.rs',
     'src/common/crc32.rs',
+    'src/common/ringbuf.rs',
     'src/common/buffer.rs',
     'src/common/usb_serial.rs',
     'src/common/display.rs',
diff --git a/src/common/lib.rs b/src/common/lib.rs
index 61d8f79..2f7d894 100644
--- a/src/common/lib.rs
+++ b/src/common/lib.rs
@@ -35,6 +35,7 @@ pub mod i2c;
 pub mod uart;
 pub mod watchdog;
 pub mod crc32;
+pub mod ringbuf;
 pub mod buffer;
 pub mod usb_serial;
 pub mod screen;
diff --git a/src/common/ringbuf.rs b/src/common/ringbuf.rs
new file mode 100644
index 0000000..2599353
--- /dev/null
+++ b/src/common/ringbuf.rs
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2019 Tilman Sauerbeck (tilman at code-monkey de)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+pub enum Ringbuf {
+}
+
+extern {
+    fn ringbuf_is_empty(ringbuf: *const Ringbuf) -> bool;
+    fn ringbuf_is_full(ringbuf: *const Ringbuf) -> bool;
+    fn ringbuf_write(ringbuf: *mut Ringbuf, value: u8);
+    fn ringbuf_read(ringbuf: *const Ringbuf) -> u8;
+}
+
+impl Ringbuf {
+    pub fn is_empty(&self) -> bool {
+        unsafe { ringbuf_is_empty(self) }
+    }
+
+    pub fn is_full(&self) -> bool {
+        unsafe { ringbuf_is_full(self) }
+    }
+
+    pub fn write(&mut self, value: u8) {
+        unsafe { ringbuf_write(self, value) }
+    }
+
+    pub fn read(&self) -> u8 {
+        unsafe { ringbuf_read(self) }
+    }
+}
-- 
2.30.2