//
// os/posix/thread.h: Multi-threading functions and types.
//
// CEN64: Cycle-Accurate Nintendo 64 Emulator.
// Copyright (C) 2015, Tyler J. Stachecki.
//
// This file is subject to the terms and conditions defined in
// 'LICENSE', which is part of this source code package.
//

#ifndef CEN64_OS_POSIX_THREAD
#define CEN64_OS_POSIX_THREAD
#include "common.h"
#include <pthread.h>
#include <sched.h>

#define CEN64_THREAD_RETURN_TYPE void*
#define CEN64_THREAD_RETURN_VAL NULL

// Type definitions.
typedef pthread_t cen64_thread;
typedef void* (*cen64_thread_func)(void *arg);

typedef pthread_mutex_t cen64_mutex;
typedef pthread_cond_t cen64_cv;

//
// Threads.
//

// Creates a thread and starts executing 'f' within the thread.
static inline int cen64_thread_create(cen64_thread *t,
  cen64_thread_func f, void *arg) {
  return pthread_create(t, NULL, f, arg);
}

//
// Returns a pointer to the currently executing thread.
//
static inline int cen64_thread_get_current(cen64_thread *t) {
  *t = pthread_self();
  return 0;
}

//
// Join a thread created with cen64_thread_create. Use this to
// effectively "free" the resources acquired for the thread.
//
static inline int cen64_thread_join(cen64_thread *t) {
  return pthread_join(*t, NULL);
}

//
// Set the affinity of a thread to the CPU mask given by mask.
// Assumes the host system has <= 32 CPUs, but good enough for now.
//
static inline int cen64_thread_setaffinity(cen64_thread *t, uint32_t mask) {
  cpu_set_t cpuset;
  unsigned i;

  CPU_ZERO(&cpuset);

  for (i = 0; mask; i++, mask >>= 1) {
    if (mask & 0x1)
      CPU_SET(i, &cpuset);
  }

  return pthread_setaffinity_np(*t, sizeof(cpuset), &cpuset);
}

//
// Mutexes.
//

// Allocates resources for/initializes a mutex.
static inline int cen64_mutex_create(cen64_mutex *m) {
  return pthread_mutex_init(m, NULL);
}

// Releases resources acquired by cen64_mutex_create.
static inline int cen64_mutex_destroy(cen64_mutex *m) {
  return pthread_mutex_destroy(m);
}

// Locks the mutex passed as an argument.
static inline int cen64_mutex_lock(cen64_mutex *m) {
  return pthread_mutex_lock(m);
}

// Unlocks the mutex passed as an argument.
static inline int cen64_mutex_unlock(cen64_mutex *m) {
  return pthread_mutex_unlock(m);
}

//
// Condition variables.
//

// Allocates resources for/initializes a CV.
static inline int cen64_cv_create(cen64_cv *cv) {
  return pthread_cond_init(cv, NULL);
}

// Releases resources acquired by cen64_cv_create.
static inline int cen64_cv_destroy(cen64_cv *cv) {
  return pthread_cond_destroy(cv);
}

// Releases the mutex and waits until cen64_cv_signal is called.
static inline int cen64_cv_wait(cen64_cv *cv, cen64_mutex *m) {
  return pthread_cond_wait(cv, m);
}

// Signals the condition variable.
static inline int cen64_cv_signal(cen64_cv *cv) {
  return pthread_cond_signal(cv);
}

#endif