当比较NSIndexPath的行和NSArray计数时，有没有更好的方法来避免“符号比较”警告？ [英] Is there a better way to avoid 'Sign comparison' warning when comparing NSIndexPath's row and NSArray count?

问题描述

我为XCode中的iOS项目打开了Signed Comparision（又名-Wsign-compare）警告（令人惊讶的是，它默认关闭）。之后，出现了很多这样的警告：

I turned 'Signed Comparision' (aka -Wsign-compare) warnings for my iOS project in XCode (surprisingly, it was off by default). After that lots of warnings like this appeared:

/Users/michalciuba/projects/GlobeMobile/Classes/ACMailController.m:86:19: Comparison of integers of different signs: 'NSInteger' (aka 'long') and 'NSUInteger' (aka 'unsigned long')

它们通常是由比较 NSIndexPath 的 row 属性引起的， NSInteger 到 NSArray 的'count'方法返回的值，如下所示：

They are usually caused by comparing row property of NSIndexPath which is NSInteger to the value returned by 'count' method of NSArray, like this:

if(indexPath.row < [self.myDataArray count]) 

警告可以简单地通过转换固定：

The warning can be simply fixed by casting:

if(indexPath.row < (NSInteger)[self.myDataArray count]) 

然而，如果每个单独的地方比较。他们正在比较的几十个地方。
我想知道是否有更好，更聪明的方法来解决这个问题？我不想关闭此警告，因为它可能有助于防止像无符号整数下溢这样的问题。

However, it has to be done if every single place where such values are being compared. And they are being compared in dozens of places. I wonder if there is a better and more clever way to solve this problem? I don't want to turn off this warning, because it may help to prevent issues like unsigned integer underflow.

推荐答案

实现一个类别为你：

@implementation NSArray (SignedCount)

- (NSInteger) signedCount
{
    NSInteger count = (NSInteger)[self count];
    return count;
}

@end

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