Semaphore.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2012 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #include "rtos/Semaphore.h"
00023 #include "platform/mbed_assert.h"
00024 
00025 #include <string.h>
00026 
00027 namespace rtos {
00028 
00029 Semaphore::Semaphore(int32_t count) {
00030     constructor(count, 0xffff);
00031 }
00032 
00033 Semaphore::Semaphore(int32_t count, uint16_t max_count) {
00034     constructor(count, max_count);
00035 }
00036 
00037 void Semaphore::constructor(int32_t count, uint16_t max_count) {
00038     memset(&_obj_mem, 0, sizeof(_obj_mem));
00039     osSemaphoreAttr_t attr = { 0 };
00040     attr.cb_mem = &_obj_mem;
00041     attr.cb_size = sizeof(_obj_mem);
00042     _id = osSemaphoreNew(max_count, count, &attr);
00043     MBED_ASSERT(_id != NULL);
00044 }
00045 
00046 int32_t Semaphore::wait(uint32_t millisec) {
00047     osStatus_t stat = osSemaphoreAcquire(_id, millisec);
00048     switch (stat) {
00049         case osOK:
00050             return osSemaphoreGetCount(_id) + 1;
00051         case osErrorTimeout:
00052         case osErrorResource:
00053             return 0;
00054         case osErrorParameter:
00055         default:
00056             return -1;
00057     }
00058 }
00059 
00060 osStatus Semaphore::release(void) {
00061     return osSemaphoreRelease(_id);
00062 }
00063 
00064 Semaphore::~Semaphore() {
00065     osSemaphoreDelete(_id);
00066 }
00067 
00068 }