From ea76b6988ccafaa6a4d4ed90f2489d0e49e1f180 Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbaren@mit.edu>
Date: Sat, 5 Sep 2015 09:32:30 -0400
Subject: Imported Upstream version 0.40.24

---
 g_src/mail.hpp | 155 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100755 g_src/mail.hpp

(limited to 'g_src/mail.hpp')

diff --git a/g_src/mail.hpp b/g_src/mail.hpp
new file mode 100755
index 0000000..b158e31
--- /dev/null
+++ b/g_src/mail.hpp
@@ -0,0 +1,155 @@
+#ifndef MAIL_H
+#define MAIL_H
+
+#include <SDL/SDL.h>
+#include <SDL/SDL_thread.h>
+#include <queue>
+
+template <typename T>
+class MBox {
+  T val;
+  SDL_sem *fill, *empty;
+public:
+  bool try_read(T &r) { // Attempt to read the mbox. Returns true if read succeeded.
+    if (SDL_SemTryWait(fill) == 0) {
+      r = val;
+      SDL_SemPost(empty);
+      return true;
+    } else
+      return false;
+  }
+  void read(T &r) {
+    SDL_SemWait(fill);
+    r = val;
+    SDL_SemPost(empty);
+  }
+  void write(const T &v) {
+    SDL_SemWait(empty);
+    val = v;
+    SDL_SemPost(fill);
+  }
+  bool try_write(const T &v) { // Returns true if the write succeeded
+    if (SDL_SemTryWait(empty) == 0) {
+      val = v;
+      SDL_SemPost(fill);
+      return true;
+    } else
+      return false;
+  }
+  MBox(T &v) {
+    MBox();
+    write(v);
+  }
+  MBox() {
+    fill  = SDL_CreateSemaphore(0);
+    empty = SDL_CreateSemaphore(1);
+  }
+  ~MBox() {
+    SDL_DestroySemaphore(fill);
+    SDL_DestroySemaphore(empty);
+  }
+};
+
+template <typename T>
+class MVar {
+  SDL_sem *s;
+public:
+  T val;
+  void lock() { SDL_SemWait(s); }
+  void unlock() { SDL_SemPost(s); }
+  MVar() { s = SDL_CreateSemaphore(1); }
+  ~MVar() { SDL_DestroySemaphore(s); }
+  void write(const T &w) { lock(); val = w; unlock(); }
+  void read(T &r) { lock(); r = val; unlock(); }
+  T read() { T r; read(r); return r; }
+};
+  
+
+template<bool start_locked = false>
+class Lock {
+  SDL_sem *s;
+public:
+  void lock() { SDL_SemWait(s); }
+  void unlock() { SDL_SemPost(s); }
+  Lock() { s = SDL_CreateSemaphore(start_locked ? 0 : 1); }
+  ~Lock() { SDL_DestroySemaphore(s); }
+};
+
+
+template<typename T>
+class Chan {
+  MVar<std::queue<T> > vals;
+  SDL_sem *fill;
+public:
+  bool try_read(T &r) {
+    if (SDL_SemTryWait(fill) == 0) {
+      vals.lock();
+      r = vals.val.front();
+      vals.val.pop();
+      vals.unlock();
+      return true;
+    } else
+      return false;
+  }
+  void read(T &r) {
+    SDL_SemWait(fill);
+    vals.lock();
+    r = vals.val.front();
+    vals.val.pop();
+    vals.unlock();
+  }
+  void write(const T &w) {
+    vals.lock();
+    vals.val.push(w);
+    vals.unlock();
+    SDL_SemPost(fill);
+  }
+  Chan() {
+    fill = SDL_CreateSemaphore(0);
+  }
+  ~Chan() {
+    SDL_DestroySemaphore(fill);
+  }
+};
+
+template<>
+class Chan<void> {
+  SDL_sem *fill;
+public:
+  bool try_read() {
+    if (SDL_SemTryWait(fill) == 0)
+      return true;
+    return false;
+  }
+  void read() {
+    SDL_SemWait(fill);
+  }
+  void write() {
+    SDL_SemPost(fill);
+  }
+  Chan() {
+    fill = SDL_CreateSemaphore(0);
+  }
+  ~Chan() {
+    SDL_DestroySemaphore(fill);
+  }
+};
+
+template<typename L, typename R>
+struct Either {
+  bool isL;
+  union {
+    L left;
+    R right;
+  };
+  Either(const L &l) {
+    isL = true;
+    left = l;
+  }
+  Either(const R &r) {
+    isL = false;
+    right = r;
+  }
+};
+
+#endif
-- 
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