Swiftgram/Source/Private/ASDispatch.h
2017-02-26 18:14:13 -08:00

33 lines
999 B
Objective-C

//
// ASDispatch.h
// AsyncDisplayKit
//
// Created by Adlai Holler on 8/25/16.
// Copyright © 2016 Facebook. All rights reserved.
//
#import <Foundation/Foundation.h>
/**
* Like dispatch_apply, but you can set the thread count. 0 means 2*active CPUs.
*
* Note: The actual number of threads may be lower than threadCount, if libdispatch
* decides the system can't handle it. In reality this rarely happens.
*/
static void ASDispatchApply(size_t iterationCount, dispatch_queue_t queue, NSUInteger threadCount, void(^work)(size_t i)) {
if (threadCount == 0) {
threadCount = [NSProcessInfo processInfo].activeProcessorCount * 2;
}
dispatch_group_t group = dispatch_group_create();
__block size_t trueI = 0;
for (NSUInteger t = 0; t < threadCount; t++) {
dispatch_group_async(group, queue, ^{
size_t i;
while ((i = __sync_fetch_and_add(&trueI, 1)) < iterationCount) {
work(i);
}
});
}
dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
};