objective-c – 如何在iOS上转换为“组合变音符号”

在我的应用程序中,我的字符后跟着他们的“修饰符变音标记”(例如“o”,其中“”是unicode 0x02c6),我想将其转换为完全预先组合的字符(例如“?” – unicode 0x00f4) .我尝试使用NSString方法precomposedStringWithCanonicalMapping,但经过几个小时的撞击墙试图弄清楚它为什么不起作用,我发现它只将“组合变音符号”( http://www.unicode.org/charts/PDF/U0300.pdf)转换为预组合字符.好吧,所以我需要做的就是将我的所有“修饰符变音符号”转换为“组合变音符号”,然后对结果字符串执行precomposedStringWithCanonicalMapping,我就完成了.这确实有效,但我想知道是否有一个不那么乏味/错误的方法来做到这一点？这是我的NSString类别方法,似乎可以修复大多数字符 –

- (instancetype)combineDiacritics
{
    static NSDictionary<NSNumber *,NSNumber *> *sDiacriticalSubstDict; //unichar of diacritic -> unichar of combining diacritic
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken,^{
        //http://www.unicode.org/charts/PDF/U0300.pdf
        sDiacriticalSubstDict = @{ @(0x02cb) : @(0x0300),@(0x00b4) : @(0x0301),@(0x02c6) : @(0x0302),@(0x02dc) : @(0x0303),@(0x02c9) : @(0x0304),//Grave,Acute,Circumflex,Tilde,Macron
                                   @(0x00af) : @(0x0305),@(0x02d8) : @(0x0306),@(0x02d9) : @(0x0307),@(0x00a8) : @(0x0308),@(0x02c0) : @(0x0309),//Overline,Breve,Dot above,Diaeresis
                                   @(0x00b0) : @(0x030a),@(0x02da) : @(0x030b),@(0x02c7) : @(0x030c),@(0x02c8) : @(0x030d),@(0x02bb) : @(0x0312),//Ring above,Double Acute,Caron,Vertical line above,Cedilla above
                                   @(0x02bc) : @(0x0313),@(0x02bd) : @(0x0314),@(0x02b2) : @(0x0321),@(0x02d4) : @(0x0323),@(0x02b1) : @(0x0324),//Comma above,Reversed comma above,Palatalized hook below,Dot below,Diaeresis below
                                   @(0x00b8) : @(0x0327),@(0x02db) : @(0x0328),@(0x02cc) : @(0x0329),@(0x02b7) : @(0x032b),@(0x02cd) : @(0x0331),//Cedilla,Ogonek,Vert line below,Inverted double arch below,Macron below
                                   };
    });
    NSMutableString* __block buffer = [NSMutableString stringWithCapacity:self.length];
    [self enumerateSubstringsInRange:NSMakeRange(0,self.length) options:NSStringEnumerationByComposedCharacterSequences usingBlock: ^(NSString* substring,NSRange substringRange,NSRange enclosingRange,BOOL* stop) {
                          NSString *newString = nil;
                          if (substring.length == 1)    //The diacriticals are all Unicode BMP.
                          {
                              unichar uniChar = [substring characterAtIndex:0];
                              unichar newUniChar = [sDiacriticalSubstDict[@(uniChar)] integerValue];
                              if (newUniChar != 0)
                              {
                                  NSLog(@"Unichar %04x => %04x",uniChar,newUniChar);
                                  newString = [NSString stringWithCharacters:&newUniChar length:1];
                              }
                          }
                          if (newString)
                              [buffer appendString:newString];
                          else
                              [buffer appendString:substring];
                      }];

    NSString *precomposedStr = [buffer precomposedStringWithCanonicalMapping];
    return precomposedStr;
}

有没有人知道更多内置的方式来进行这种转换？