From 4c2492e9854c220694b20d7b6b06048b089c80ec Mon Sep 17 00:00:00 2001
From: Drew Galbraith <dgalbraith33@gmail.com>
Date: Wed, 22 Nov 2023 10:55:40 -0800
Subject: [PATCH] [Mammoth] Add a user-space semaphore object.

---
 lib/mammoth/CMakeLists.txt              |  1 +
 lib/mammoth/include/mammoth/semaphore.h | 15 +++++++++++++++
 lib/mammoth/src/semaphore.cpp           | 11 +++++++++++
 3 files changed, 27 insertions(+)
 create mode 100644 lib/mammoth/include/mammoth/semaphore.h
 create mode 100644 lib/mammoth/src/semaphore.cpp

diff --git a/lib/mammoth/CMakeLists.txt b/lib/mammoth/CMakeLists.txt
index f8ce74a..b33c991 100644
--- a/lib/mammoth/CMakeLists.txt
+++ b/lib/mammoth/CMakeLists.txt
@@ -10,6 +10,7 @@ add_library(mammoth STATIC
   src/process.cpp
   src/port_client.cpp
   src/port_server.cpp
+  src/semaphore.cpp
   src/thread.cpp
   )
 
diff --git a/lib/mammoth/include/mammoth/semaphore.h b/lib/mammoth/include/mammoth/semaphore.h
new file mode 100644
index 0000000..b22c124
--- /dev/null
+++ b/lib/mammoth/include/mammoth/semaphore.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <ztypes.h>
+
+class Semaphore {
+ public:
+  Semaphore();
+  ~Semaphore();
+
+  void Wait();
+  void Signal();
+
+ private:
+  z_cap_t semaphore_cap_;
+};
diff --git a/lib/mammoth/src/semaphore.cpp b/lib/mammoth/src/semaphore.cpp
new file mode 100644
index 0000000..f6e348d
--- /dev/null
+++ b/lib/mammoth/src/semaphore.cpp
@@ -0,0 +1,11 @@
+#include "mammoth/semaphore.h"
+
+#include <zcall.h>
+
+#include "mammoth/debug.h"
+
+Semaphore::Semaphore() { check(ZSemaphoreCreate(&semaphore_cap_)); }
+Semaphore::~Semaphore() { check(ZCapRelease(semaphore_cap_)); }
+
+void Semaphore::Wait() { check(ZSemaphoreWait(semaphore_cap_)); }
+void Semaphore::Signal() { check(ZSemaphoreSignal(semaphore_cap_)); }