| 1 | /* |
| 2 | SDL - Simple DirectMedia Layer |
| 3 | Copyright (C) 1997-2009 Sam Lantinga |
| 4 | |
| 5 | This library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | This library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with this library; if not, write to the Free Software |
| 17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | |
| 19 | Sam Lantinga |
| 20 | slouken@libsdl.org |
| 21 | */ |
| 22 | #include "SDL_config.h" |
| 23 | |
| 24 | /* Semaphore functions using the Win32 API */ |
| 25 | |
| 26 | #define WIN32_LEAN_AND_MEAN |
| 27 | #include <windows.h> |
| 28 | |
| 29 | #include "SDL_thread.h" |
| 30 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
| 31 | #include "win_ce_semaphore.h" |
| 32 | #endif |
| 33 | |
| 34 | |
| 35 | struct SDL_semaphore { |
| 36 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
| 37 | SYNCHHANDLE id; |
| 38 | #else |
| 39 | HANDLE id; |
| 40 | #endif |
| 41 | Uint32 volatile count; |
| 42 | }; |
| 43 | |
| 44 | |
| 45 | /* Create a semaphore */ |
| 46 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
| 47 | { |
| 48 | SDL_sem *sem; |
| 49 | |
| 50 | /* Allocate sem memory */ |
| 51 | sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); |
| 52 | if ( sem ) { |
| 53 | /* Create the semaphore, with max value 32K */ |
| 54 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
| 55 | sem->id = CreateSemaphoreCE(NULL, initial_value, 32*1024, NULL); |
| 56 | #else |
| 57 | sem->id = CreateSemaphore(NULL, initial_value, 32*1024, NULL); |
| 58 | #endif |
| 59 | sem->count = initial_value; |
| 60 | if ( ! sem->id ) { |
| 61 | SDL_SetError("Couldn't create semaphore"); |
| 62 | SDL_free(sem); |
| 63 | sem = NULL; |
| 64 | } |
| 65 | } else { |
| 66 | SDL_OutOfMemory(); |
| 67 | } |
| 68 | return(sem); |
| 69 | } |
| 70 | |
| 71 | /* Free the semaphore */ |
| 72 | void SDL_DestroySemaphore(SDL_sem *sem) |
| 73 | { |
| 74 | if ( sem ) { |
| 75 | if ( sem->id ) { |
| 76 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
| 77 | CloseSynchHandle(sem->id); |
| 78 | #else |
| 79 | CloseHandle(sem->id); |
| 80 | #endif |
| 81 | sem->id = 0; |
| 82 | } |
| 83 | SDL_free(sem); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
| 88 | { |
| 89 | int retval; |
| 90 | DWORD dwMilliseconds; |
| 91 | |
| 92 | if ( ! sem ) { |
| 93 | SDL_SetError("Passed a NULL sem"); |
| 94 | return -1; |
| 95 | } |
| 96 | |
| 97 | if ( timeout == SDL_MUTEX_MAXWAIT ) { |
| 98 | dwMilliseconds = INFINITE; |
| 99 | } else { |
| 100 | dwMilliseconds = (DWORD)timeout; |
| 101 | } |
| 102 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
| 103 | switch (WaitForSemaphoreCE(sem->id, dwMilliseconds)) { |
| 104 | #else |
| 105 | switch (WaitForSingleObject(sem->id, dwMilliseconds)) { |
| 106 | #endif |
| 107 | case WAIT_OBJECT_0: |
| 108 | InterlockedDecrement(&sem->count); |
| 109 | retval = 0; |
| 110 | break; |
| 111 | case WAIT_TIMEOUT: |
| 112 | retval = SDL_MUTEX_TIMEDOUT; |
| 113 | break; |
| 114 | default: |
| 115 | SDL_SetError("WaitForSingleObject() failed"); |
| 116 | retval = -1; |
| 117 | break; |
| 118 | } |
| 119 | return retval; |
| 120 | } |
| 121 | |
| 122 | int SDL_SemTryWait(SDL_sem *sem) |
| 123 | { |
| 124 | return SDL_SemWaitTimeout(sem, 0); |
| 125 | } |
| 126 | |
| 127 | int SDL_SemWait(SDL_sem *sem) |
| 128 | { |
| 129 | return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); |
| 130 | } |
| 131 | |
| 132 | /* Returns the current count of the semaphore */ |
| 133 | Uint32 SDL_SemValue(SDL_sem *sem) |
| 134 | { |
| 135 | if ( ! sem ) { |
| 136 | SDL_SetError("Passed a NULL sem"); |
| 137 | return 0; |
| 138 | } |
| 139 | return sem->count; |
| 140 | } |
| 141 | |
| 142 | int SDL_SemPost(SDL_sem *sem) |
| 143 | { |
| 144 | if ( ! sem ) { |
| 145 | SDL_SetError("Passed a NULL sem"); |
| 146 | return -1; |
| 147 | } |
| 148 | /* Increase the counter in the first place, because |
| 149 | * after a successful release the semaphore may |
| 150 | * immediately get destroyed by another thread which |
| 151 | * is waiting for this semaphore. |
| 152 | */ |
| 153 | InterlockedIncrement(&sem->count); |
| 154 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
| 155 | if ( ReleaseSemaphoreCE(sem->id, 1, NULL) == FALSE ) { |
| 156 | #else |
| 157 | if ( ReleaseSemaphore(sem->id, 1, NULL) == FALSE ) { |
| 158 | #endif |
| 159 | InterlockedDecrement(&sem->count); /* restore */ |
| 160 | SDL_SetError("ReleaseSemaphore() failed"); |
| 161 | return -1; |
| 162 | } |
| 163 | return 0; |
| 164 | } |