src/thread/windows/SDL_sysmutex.c
author Sam Lantinga <slouken@libsdl.org>
Sun, 01 Jan 2017 18:33:28 -0800
changeset 10737 3406a0f8b041
parent 9998 f67cf37e9cd4
child 11811 5d94cb6b24d3
permissions -rw-r--r--
Updated copyright for 2017
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 #include "../../SDL_internal.h"
    22 
    23 #if SDL_THREAD_WINDOWS
    24 
    25 /* Mutex functions using the Win32 API */
    26 
    27 #include "../../core/windows/SDL_windows.h"
    28 
    29 #include "SDL_mutex.h"
    30 
    31 
    32 struct SDL_mutex
    33 {
    34     CRITICAL_SECTION cs;
    35 };
    36 
    37 /* Create a mutex */
    38 SDL_mutex *
    39 SDL_CreateMutex(void)
    40 {
    41     SDL_mutex *mutex;
    42 
    43     /* Allocate mutex memory */
    44     mutex = (SDL_mutex *) SDL_malloc(sizeof(*mutex));
    45     if (mutex) {
    46         /* Initialize */
    47         /* On SMP systems, a non-zero spin count generally helps performance */
    48 #if __WINRT__
    49         InitializeCriticalSectionEx(&mutex->cs, 2000, 0);
    50 #else
    51         InitializeCriticalSectionAndSpinCount(&mutex->cs, 2000);
    52 #endif
    53     } else {
    54         SDL_OutOfMemory();
    55     }
    56     return (mutex);
    57 }
    58 
    59 /* Free the mutex */
    60 void
    61 SDL_DestroyMutex(SDL_mutex * mutex)
    62 {
    63     if (mutex) {
    64         DeleteCriticalSection(&mutex->cs);
    65         SDL_free(mutex);
    66     }
    67 }
    68 
    69 /* Lock the mutex */
    70 int
    71 SDL_LockMutex(SDL_mutex * mutex)
    72 {
    73     if (mutex == NULL) {
    74         return SDL_SetError("Passed a NULL mutex");
    75     }
    76 
    77     EnterCriticalSection(&mutex->cs);
    78     return (0);
    79 }
    80 
    81 /* TryLock the mutex */
    82 int
    83 SDL_TryLockMutex(SDL_mutex * mutex)
    84 {
    85     int retval = 0;
    86     if (mutex == NULL) {
    87         return SDL_SetError("Passed a NULL mutex");
    88     }
    89 
    90     if (TryEnterCriticalSection(&mutex->cs) == 0) {
    91         retval = SDL_MUTEX_TIMEDOUT;
    92     }
    93     return retval;
    94 }
    95 
    96 /* Unlock the mutex */
    97 int
    98 SDL_UnlockMutex(SDL_mutex * mutex)
    99 {
   100     if (mutex == NULL) {
   101         return SDL_SetError("Passed a NULL mutex");
   102     }
   103 
   104     LeaveCriticalSection(&mutex->cs);
   105     return (0);
   106 }
   107 
   108 #endif /* SDL_THREAD_WINDOWS */
   109 
   110 /* vi: set ts=4 sw=4 expandtab: */