vpx: Add OS/2-specific threading codes

With correction of a type of a thread function for new threading
codes.

Change-Id: Ic6dc9f530698800d1cfe2da327848e8f8b62e31f

vp8/common/threading.h

@@ -44,8 +44,8 @@ extern "C" {
 #include <os2.h>
 
 #include <stdlib.h>
-#define THREAD_FUNCTION void
-#define THREAD_FUNCTION_RETURN void
+#define THREAD_FUNCTION void *
+#define THREAD_FUNCTION_RETURN void *
 #define THREAD_SPECIFIC_INDEX PULONG
 #define pthread_t TID
 #define pthread_attr_t ULONG

vpx_util/vpx_thread.h

@@ -147,6 +147,152 @@ static INLINE int pthread_cond_wait(pthread_cond_t *const condition,
   pthread_mutex_lock(mutex);
   return !ok;
 }
+#elif defined(__OS2__)
+#define INCL_DOS
+#include <os2.h>    // NOLINT
+
+#include <errno.h>  // NOLINT
+#include <stdlib.h> // NOLINT
+#include <sys/builtin.h> // NOLINT
+
+#define pthread_t TID
+#define pthread_mutex_t HMTX
+
+typedef struct {
+  HEV event_sem_;
+  HEV ack_sem_;
+  volatile unsigned wait_count_;
+} pthread_cond_t;
+
+//------------------------------------------------------------------------------
+// simplistic pthread emulation layer
+
+#define THREADFN void *
+#define THREAD_RETURN(val) (val)
+
+typedef struct {
+  void* (*start_)(void*);
+  void* arg_;
+} thread_arg;
+
+static void thread_start(void* arg) {
+  thread_arg targ = *(thread_arg *)arg;
+  free(arg);
+
+  targ.start_(targ.arg_);
+}
+
+static INLINE int pthread_create(pthread_t* const thread, const void* attr,
+                                 void* (*start)(void*),
+                                 void* arg) {
+  int tid;
+  thread_arg *targ = (thread_arg *)malloc(sizeof(*targ));
+  if (targ == NULL) return 1;
+
+  (void)attr;
+
+  targ->start_ = start;
+  targ->arg_ = arg;
+  tid = (pthread_t)_beginthread(thread_start, NULL, 1024 * 1024, targ);
+  if (tid == -1) {
+    free(targ);
+    return 1;
+  }
+
+  *thread = tid;
+  return 0;
+}
+
+static INLINE int pthread_join(pthread_t thread, void** value_ptr) {
+  (void)value_ptr;
+  return DosWaitThread(&thread, DCWW_WAIT) != 0;
+}
+
+// Mutex
+static INLINE int pthread_mutex_init(pthread_mutex_t *const mutex,
+                                     void* mutexattr) {
+  (void)mutexattr;
+  return DosCreateMutexSem(NULL, mutex, 0, FALSE) != 0;
+}
+
+static INLINE int pthread_mutex_trylock(pthread_mutex_t *const mutex) {
+  return DosRequestMutexSem(*mutex, SEM_IMMEDIATE_RETURN) == 0 ? 0 : EBUSY;
+}
+
+static INLINE int pthread_mutex_lock(pthread_mutex_t *const mutex) {
+  return DosRequestMutexSem(*mutex, SEM_INDEFINITE_WAIT) != 0;
+}
+
+static INLINE int pthread_mutex_unlock(pthread_mutex_t *const mutex) {
+  return DosReleaseMutexSem(*mutex) != 0;
+}
+
+static INLINE int pthread_mutex_destroy(pthread_mutex_t *const mutex) {
+  return DosCloseMutexSem(*mutex) != 0;
+}
+
+// Condition
+static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) {
+  int ok = 1;
+  ok &= DosCloseEventSem(condition->event_sem_) == 0;
+  ok &= DosCloseEventSem(condition->ack_sem_) == 0;
+  return !ok;
+}
+
+static INLINE int pthread_cond_init(pthread_cond_t *const condition,
+                                    void* cond_attr) {
+  int ok = 1;
+  (void)cond_attr;
+
+  ok &= DosCreateEventSem(NULL, &condition->event_sem_, DCE_POSTONE, FALSE)
+          == 0;
+  ok &= DosCreateEventSem(NULL, &condition->ack_sem_, DCE_POSTONE, FALSE) == 0;
+  if (!ok) {
+    pthread_cond_destroy(condition);
+    return 1;
+  }
+  condition->wait_count_ = 0;
+  return 0;
+}
+
+static INLINE int pthread_cond_signal(pthread_cond_t *const condition) {
+  int ok = 1;
+
+  if (!__atomic_cmpxchg32(&condition->wait_count_, 0, 0)) {
+    ok &= DosPostEventSem(condition->event_sem_) == 0;
+    ok &= DosWaitEventSem(condition->ack_sem_, SEM_INDEFINITE_WAIT) == 0;
+  }
+
+  return !ok;
+}
+
+static INLINE int pthread_cond_broadcast(pthread_cond_t *const condition) {
+  int ok = 1;
+
+  while (!__atomic_cmpxchg32(&condition->wait_count_, 0, 0))
+      ok &= pthread_cond_signal(condition) == 0;
+
+  return !ok;
+}
+
+static INLINE int pthread_cond_wait(pthread_cond_t *const condition,
+                                    pthread_mutex_t *const mutex) {
+  int ok = 1;
+
+  __atomic_increment(&condition->wait_count_);
+
+  ok &= pthread_mutex_unlock(mutex) == 0;
+
+  ok &= DosWaitEventSem(condition->event_sem_, SEM_INDEFINITE_WAIT) == 0;
+
+  __atomic_decrement(&condition->wait_count_);
+
+  ok &= DosPostEventSem(condition->ack_sem_) == 0;
+
+  pthread_mutex_lock(mutex);
+
+  return !ok;
+}
 #else  // _WIN32
 #include <pthread.h> // NOLINT
 # define THREADFN void*