/**
* Copyright (c) 2016 Tino Reichardt
* All rights reserved.
*
* You can contact the author at:
* - zstdmt source repository: https://github.com/mcmilk/zstdmt
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/

/**
* This file will hold wrapper for systems, which do not support pthreads
*/

#include "threading.h"

/* create fake symbol to avoid empty translation unit warning */
int g_ZSTD_threading_useless_symbol;

#if defined(ZSTD_MULTITHREAD) && defined(_WIN32)

/**
* Windows minimalist Pthread Wrapper
*/


/* ===  Dependencies  === */
#include <process.h>
#include <errno.h>


/* ===  Implementation  === */

typedef struct {
   void* (*start_routine)(void*);
   void* arg;
   int initialized;
   ZSTD_pthread_cond_t initialized_cond;
   ZSTD_pthread_mutex_t initialized_mutex;
} ZSTD_thread_params_t;

static unsigned __stdcall worker(void *arg)
{
   void* (*start_routine)(void*);
   void* thread_arg;

   /* Initialized thread_arg and start_routine and signal main thread that we don't need it
    * to wait any longer.
    */
   {
       ZSTD_thread_params_t*  thread_param = (ZSTD_thread_params_t*)arg;
       thread_arg = thread_param->arg;
       start_routine = thread_param->start_routine;

       /* Signal main thread that we are running and do not depend on its memory anymore */
       ZSTD_pthread_mutex_lock(&thread_param->initialized_mutex);
       thread_param->initialized = 1;
       ZSTD_pthread_cond_signal(&thread_param->initialized_cond);
       ZSTD_pthread_mutex_unlock(&thread_param->initialized_mutex);
   }

   start_routine(thread_arg);

   return 0;
}

int ZSTD_pthread_create(ZSTD_pthread_t* thread, const void* unused,
           void* (*start_routine) (void*), void* arg)
{
   ZSTD_thread_params_t thread_param;
   (void)unused;

   if (thread==NULL) return -1;
   *thread = NULL;

   thread_param.start_routine = start_routine;
   thread_param.arg = arg;
   thread_param.initialized = 0;

   /* Setup thread initialization synchronization */
   if(ZSTD_pthread_cond_init(&thread_param.initialized_cond, NULL)) {
       /* Should never happen on Windows */
       return -1;
   }
   if(ZSTD_pthread_mutex_init(&thread_param.initialized_mutex, NULL)) {
       /* Should never happen on Windows */
       ZSTD_pthread_cond_destroy(&thread_param.initialized_cond);
       return -1;
   }

   /* Spawn thread */
   *thread = (HANDLE)_beginthreadex(NULL, 0, worker, &thread_param, 0, NULL);
   if (*thread==NULL) {
       ZSTD_pthread_mutex_destroy(&thread_param.initialized_mutex);
       ZSTD_pthread_cond_destroy(&thread_param.initialized_cond);
       return errno;
   }

   /* Wait for thread to be initialized */
   ZSTD_pthread_mutex_lock(&thread_param.initialized_mutex);
   while(!thread_param.initialized) {
       ZSTD_pthread_cond_wait(&thread_param.initialized_cond, &thread_param.initialized_mutex);
   }
   ZSTD_pthread_mutex_unlock(&thread_param.initialized_mutex);
   ZSTD_pthread_mutex_destroy(&thread_param.initialized_mutex);
   ZSTD_pthread_cond_destroy(&thread_param.initialized_cond);

   return 0;
}

int ZSTD_pthread_join(ZSTD_pthread_t thread)
{
   DWORD result;

   if (!thread) return 0;

   result = WaitForSingleObject(thread, INFINITE);
   CloseHandle(thread);

   switch (result) {
   case WAIT_OBJECT_0:
       return 0;
   case WAIT_ABANDONED:
       return EINVAL;
   default:
       return GetLastError();
   }
}

#endif   /* ZSTD_MULTITHREAD */

#if defined(ZSTD_MULTITHREAD) && DEBUGLEVEL >= 1 && !defined(_WIN32)

#define ZSTD_DEPS_NEED_MALLOC
#include "zstd_deps.h"

int ZSTD_pthread_mutex_init(ZSTD_pthread_mutex_t* mutex, pthread_mutexattr_t const* attr)
{
   assert(mutex != NULL);
   *mutex = (pthread_mutex_t*)ZSTD_malloc(sizeof(pthread_mutex_t));
   if (!*mutex)
       return 1;
   return pthread_mutex_init(*mutex, attr);
}

int ZSTD_pthread_mutex_destroy(ZSTD_pthread_mutex_t* mutex)
{
   assert(mutex != NULL);
   if (!*mutex)
       return 0;
   {
       int const ret = pthread_mutex_destroy(*mutex);
       ZSTD_free(*mutex);
       return ret;
   }
}

int ZSTD_pthread_cond_init(ZSTD_pthread_cond_t* cond, pthread_condattr_t const* attr)
{
   assert(cond != NULL);
   *cond = (pthread_cond_t*)ZSTD_malloc(sizeof(pthread_cond_t));
   if (!*cond)
       return 1;
   return pthread_cond_init(*cond, attr);
}

int ZSTD_pthread_cond_destroy(ZSTD_pthread_cond_t* cond)
{
   assert(cond != NULL);
   if (!*cond)
       return 0;
   {
       int const ret = pthread_cond_destroy(*cond);
       ZSTD_free(*cond);
       return ret;
   }
}

#endif