在 arm64 上使用 NSScanner 处理 CGFloat [英] Handling CGFloat with an NSScanner on arm64
问题描述
显然 CGFloat
在 arm64 上是 double
:
Apparently CGFloat
is double
on arm64:
#if defined(__LP64__) && __LP64__
# define CGFLOAT_TYPE double
# define CGFLOAT_IS_DOUBLE 1
# define CGFLOAT_MIN DBL_MIN
# define CGFLOAT_MAX DBL_MAX
#else
# define CGFLOAT_TYPE float
# define CGFLOAT_IS_DOUBLE 0
# define CGFLOAT_MIN FLT_MIN
# define CGFLOAT_MAX FLT_MAX
#endif
所以代码
NSScanner *scanner = [NSScanner scannerWithString:string];
CGFloat c[components];
[scanner scanFloat:&c[i]]
在 32 位应用程序中运行良好,在 64 位应用程序中损坏.可以换成
which was working fine for 32-bit apps, is broken for 64-bit. It can be replaced with
NSScanner *scanner = [NSScanner scannerWithString:string];
CGFloat c[components];
#if CGFLOAT_IS_DOUBLE
[scanner scanDouble:&c[i]];
#else
[scanner scanFloat:&c[i]];
#endif
但是还有更好的选择吗?
But is there a better alternative?
推荐答案
NSScanner
仅支持 一些基本类型,因此您需要在某处使用#if 指令.也就是说,如果您经常使用它,您可以继承 NSScanner 或使用 category 让代码更优雅.
NSScanner
only supports a few basic types, so you're going to need to have that #if directive somewhere. That said, if you're using this often you could subclass NSScanner or use a category to make the code more elegant.
我认为基于类别的代码如下所示:
I think the category-based code would look something like:
NSScanner+MyAdditions.h:
NSScanner+MyAdditions.h:
#import "NSScanner.h"
@interface NSScanner (MyAdditions)
- (BOOL)my_scanCGFloat:(CGFloat *) cgFloatValue
@end
NSScanner+MyAdditions.m:
NSScanner+MyAdditions.m:
#import "NSScanner+MyAdditions.h"
@implementation NSScanner (MyAdditions)
- (BOOL)my_scanCGFloat:(CGFloat *) cgFloatValue {
#if CGFLOAT_IS_DOUBLE
return [self scanDouble:cgFloatValue];
#else
return [self scanFloat:cgFloatValue];
#endif
}
@end
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