Binary unit transform

BinaryUnitTransform.m

typedef NS_ENUM(NSUInteger, BinaryUnit) {
    b,
    B,
    KB,
    MB,
    GB,
    TB,
    PB,
    ZB,
    YB
};
+ (NSString*)binaryUnitTranform:(double)value withUnit:(BinaryUnit)unit;




+ (NSString*)binaryUnitTranform:(double)value withUnit:(BinaryUnit)unit
{
    if (value < 1.0 && value > 0 && unit > b) {
        return [self binaryUnitTranform:value*1024.0 withUnit:--unit];
    } else if (value > 1024.0 && unit < YB) {
        return [self binaryUnitTranform:value/1024.0 withUnit:++unit];
    } else {
        NSDictionary *units = @{@(b):@"b",
                           @(B):@"B",
                           @(KB):@"KB",
                           @(MB):@"MB",
                           @(GB):@"GB",
                           @(TB):@"TB",
                           @(PB):@"PB",
                           @(ZB):@"ZB",
                           @(YB):@"YB"};
        return [NSString stringWithFormat:@"%.2f%@", value, units[@(unit)]];
    }
}