Project reordering and mpmc code

lf_mpmc.h

@@ -2,6 +2,7 @@
 
 #include "base.h"
 
+// Cache align abstraction
 #define CACHELINE 64
 
 #if defined(_MSC_VER)
@@ -10,6 +11,7 @@
 #define CACHE_ALIGN __attribute__((aligned(CACHELINE)))
 #endif
 
+// Compiler hints
 #if defined(__GNUC__) || defined(__clang__)
 #define likely(x) __builtin_expect((x), 1)
 #define unlikely(x) __builtin_expect((x), 0)
@@ -24,6 +26,65 @@ static void cpu_pause(void) {
 #endif
 }
 
+// Semaphores
+#if defined(_WIN32) || defined(_WIN64)
+typedef struct plat_sem {
+  HANDLE handle;
+} plat_sem;
+
+static b32 plat_sem_init(plat_sem *s, u32 initial) {
+  s->handle = CreateSemaphore(NULL, initial, LONG_MAX, NULL);
+  return s->handle != NULL;
+}
+
+static void plat_sem_wait(plat_sem *s) {
+  WaitForSingleObject(s->handle, INFINITE);
+}
+
+// static b32 plat_sem_trywait(HANDLE sem) { // Comment to prevent warning: unused function
+//   DWORD r = WaitForSingleObject(sem, 0);
+//   return r == WAIT_OBJECT_0;
+// }
+
+static void plat_sem_post(plat_sem *s, u32 count) {
+  ReleaseSemaphore(s->handle, count, NULL);
+}
+
+// static void plat_sem_destroy(plat_sem *s) { // Comment to prevent warning: unused function
+//   if (s->handle) {
+//     CloseHandle(s->handle);
+//     s->handle = NULL;
+//   }
+// }
+
+#elif defined(__linux__)
+#include <semaphore.h>
+
+typedef struct plat_sem {
+  sem_t sem;
+} plat_sem;
+
+static b32 plat_sem_init(plat_sem *s, u32 initial) {
+  return sem_init(&s->sem, 0, initial) == 0;
+}
+
+static void plat_sem_wait(plat_sem *s) {
+  while (sem_wait(&s->sem) == -1 && errno == EINTR) {
+  }
+}
+
+// static b32 plat_sem_trywait(sem_t *sem) { return sem_trywait(sem) == 0; } // Comment to prevent warning: unused function
+
+static void plat_sem_post(plat_sem *s, u32 count) {
+  for (u32 i = 0; i < count; i++) {
+    sem_post(&s->sem);
+  }
+}
+
+// static void plat_sem_destroy(plat_sem *s) { sem_destroy(&s->sem); } // Comment to prevent warning: unused function
+
+#endif
+
 typedef struct plat_sem plat_sem;
 
 typedef struct CACHE_ALIGN {
@@ -235,6 +296,7 @@ static void mpmc_push_work(MPMCQueue *q, void *item) {
   atomic_fetch_add(&q->work_count, 1);
   plat_sem_post(&q->items_sem, 1);
 }
+
 /* ----------------------------------------------------------- */
 /* POP */
 /* ----------------------------------------------------------- */