refactor dependencies; include dependencies source code

1 files changed, 181 insertions, 0 deletions

diff --git a/source/kit/shared_mutex.h b/source/kit/shared_mutex.h
new file mode 100644
index 0000000..3626939
--- /dev/null
+++ b/source/kit/shared_mutex.h
@@ -0,0 +1,181 @@
+//  Shared mutex can be used in shared memory for interprocess
+//  synchronization.
+//
+
+#ifndef KIT_SHARED_MUTEX_H
+#define KIT_SHARED_MUTEX_H
+
+#include "atomic.h"
+#include "threads.h"
+
+#include <assert.h>
+#include <string.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wunused-function"
+#  pragma GCC diagnostic ignored "-Wunknown-pragmas"
+#  pragma GCC            push_options
+#  pragma GCC            optimize("O3")
+#endif
+
+enum {
+  KIT_SHARED_MUTEX_READY = 1,
+  KIT_SHARED_MUTEX_LOCKED,
+  KIT_SHARED_MUTEX_WRITER
+};
+
+typedef union {
+  struct {
+    i8 _Atomic state;
+    i32        readers;
+  };
+  struct {
+    u8 _pad[16];
+  };
+} kit_shared_mutex_t;
+
+static void kit_shared_mutex_init(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+  memset(m, 0, sizeof *m);
+
+  atomic_store_explicit(&m->state, KIT_SHARED_MUTEX_READY,
+                        memory_order_relaxed);
+}
+
+static i8 kit_shared_try_lock(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+
+  for (;;) {
+    i8 prev_state = KIT_SHARED_MUTEX_READY;
+    if (atomic_compare_exchange_strong_explicit(
+            &m->state, &prev_state, KIT_SHARED_MUTEX_LOCKED,
+            memory_order_seq_cst, memory_order_seq_cst))
+      break;
+    if (prev_state == KIT_SHARED_MUTEX_WRITER)
+      return 0;
+    //  FIXME
+    //  Check performance
+    thrd_yield();
+  }
+
+  assert(m->readers >= 0);
+  ++m->readers;
+
+  i8 prev_state = KIT_SHARED_MUTEX_LOCKED;
+  if (!atomic_compare_exchange_strong_explicit(
+          &m->state, &prev_state, KIT_SHARED_MUTEX_READY,
+          memory_order_seq_cst, memory_order_seq_cst))
+    assert(0);
+
+  return 1;
+}
+
+static void kit_shared_lock(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+
+  while (!kit_shared_try_lock(m))
+    //  FIXME
+    //  Check performance
+    thrd_yield();
+}
+
+static void kit_shared_unlock(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+
+  for (;;) {
+    i8 prev_state = KIT_SHARED_MUTEX_READY;
+    if (atomic_compare_exchange_strong_explicit(
+            &m->state, &prev_state, KIT_SHARED_MUTEX_LOCKED,
+            memory_order_seq_cst, memory_order_seq_cst))
+      break;
+    //  FIXME
+    //  Check performance
+    thrd_yield();
+  }
+
+  assert(m->readers > 0);
+  m->readers--;
+
+  i8 prev_state = KIT_SHARED_MUTEX_LOCKED;
+  if (!atomic_compare_exchange_strong_explicit(
+          &m->state, &prev_state, KIT_SHARED_MUTEX_READY,
+          memory_order_seq_cst, memory_order_seq_cst))
+    assert(0);
+}
+
+static i8 kit_unique_try_lock(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+
+  i8 prev_state = KIT_SHARED_MUTEX_READY;
+  if (!atomic_compare_exchange_strong_explicit(
+          &m->state, &prev_state, KIT_SHARED_MUTEX_WRITER,
+          memory_order_seq_cst, memory_order_seq_cst))
+    return 0;
+
+  i8 is_locked = (m->readers == 0);
+
+  prev_state = KIT_SHARED_MUTEX_WRITER;
+  if (!is_locked &&
+      !atomic_compare_exchange_strong_explicit(
+          &m->state, &prev_state, KIT_SHARED_MUTEX_READY,
+          memory_order_seq_cst, memory_order_seq_cst))
+    assert(0);
+
+  return is_locked;
+}
+
+static void kit_unique_lock(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+
+  while (!kit_unique_try_lock(m))
+    //  FIXME
+    //  Check performance
+    thrd_yield();
+}
+
+static void kit_unique_unlock(kit_shared_mutex_t *m) {
+  assert(m != NULL);
+
+  i8 prev_state = KIT_SHARED_MUTEX_WRITER;
+  if (!atomic_compare_exchange_strong_explicit(
+          &m->state, &prev_state, KIT_SHARED_MUTEX_READY,
+          memory_order_seq_cst, memory_order_seq_cst))
+    assert(0);
+}
+
+#if defined(__GNUC__) || defined(__clang__)
+#  pragma GCC            pop_options
+#  pragma GCC diagnostic pop
+#endif
+
+#ifndef KIT_DISABLE_SHORT_NAMES
+#  define shared_mutex_t kit_shared_mutex_t
+#  define shared_mutex_init kit_shared_mutex_init
+#  define shared_try_lock kit_shared_try_lock
+#  define shared_lock kit_shared_lock
+#  define shared_unlock kit_shared_unlock
+#  define unique_try_lock kit_unique_try_lock
+#  define unique_lock kit_unique_lock
+#  define unique_unlock kit_unique_unlock
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#ifndef KIT_DISABLE_SHORT_NAMES
+#  define shared_mutex_init kit_shared_mutex_init
+#  define shared_try_lock kit_shared_try_lock
+#  define shared_lock kit_shared_lock
+#  define shared_unlock kit_shared_unlock
+#  define unique_try_lock kit_unique_try_lock
+#  define unique_lock kit_unique_lock
+#  define unique_unlock kit_unique_unlock
+#endif
+
+#endif