//加入頭文件
#import <sys/sysctl.h>
#import <mach/mach.h>

  //獲取當前設(shè)備可用內(nèi)存
 + (double)availableMemory{
      vm_statistics_data_t vmStats;
      mach_msg_type_number_t infoCount = HOST_VM_INFO_COUNT;
      kern_return_t kernReturn = host_statistics(mach_host_self(),
                                           HOST_VM_INFO,
                                           (host_info_t)&vmStats,
                                           &infoCount);

    if (kernReturn != KERN_SUCCESS) {
    return NSNotFound;
    }
    return ((vm_page_size * vmStats.free_count)/1024.0)/1024.0;
}

//獲取當前任務(wù)所占用內(nèi)存
+ (double)usedMemory{
    task_basic_info_data_t taskInfo;
    mach_msg_type_number_t infoCount = TASK_BASIC_INFO_COUNT;
    kern_return_t kernReturn = task_info(mach_task_self(),
                                     TASK_BASIC_INFO,
                                     (task_info_t)&taskInfo,
                                     &infoCount);

      if (kernReturn != KERN_SUCCESS) {
      return NSNotFound;
      }
      return taskInfo.resident_size/1024.0/1024.0;
}