PinyinUtil for finding the diacritic's position, removing diacritics in a pinyin string or transforming Mandarine to pinyin on iOS platform written by Objective-C

PinyinUtil.m

+ (void)test {
    NSString *zhua = @"zhuā";
    NSString *tong = @"tóng";
    NSString *bie = @"biě";
    NSString *yi = @"yì";
    
    int zhuaPosition = [self detectDiacriticsPosition:zhua]; // 输出1
    NSLog(@"%@%d", zhua, zhuaPosition);
    int tongPosition = [self detectDiacriticsPosition:tong]; // 输出2
    NSLog(@"%@%d", tong, tongPosition);
    int biePosition = [self detectDiacriticsPosition:bie];   // 输出3
    NSLog(@"%@%d", bie, biePosition);
    int yiPosition = [self detectDiacriticsPosition:yi];     // 输出4
    NSLog(@"%@%d", yi, yiPosition);
    
    
    NSString *zhongGuo = @"中国";
    NSString *tiananMen = @"天安门";
    NSString *ziJinCheng = @"紫禁城";
    NSString *zhongGuoPinyin = [self transferMandarinToPinyin:zhongGuo];
    NSLog(@"%@=%@", zhongGuo, zhongGuoPinyin);    // 输出 中国=zhōng guó
    NSString *tiananMenPinyin = [self transferMandarinToPinyin:tiananMen];
    NSLog(@"%@=%@", tiananMen, tiananMenPinyin);  // 输出 天安门=tiān ān mén
    NSString *ziJinChengPinyin = [self transferMandarinToPinyin:ziJinCheng];
    NSLog(@"%@=%@", ziJinCheng, ziJinChengPinyin);// 输出 紫禁城=zǐ jìn chéng
    
    
    NSLog(@"%@", [self stripPinyinDiacritics:zhongGuoPinyin]);  // 输出 zhōng guó = zhong guo
    NSLog(@"%@", [self stripPinyinDiacritics:tiananMenPinyin]); // 输出 tiān ān mén = tian an men
    NSLog(@"%@", [self stripPinyinDiacritics:ziJinChengPinyin]);// 输出 zǐ jìn chéng = zi jin cheng
}

/**
 * 将汉字转换为拼音，且带上注音（变音）符号
 * 遇到多音字时，默认会返回第一个发音，（默认排序未知）
 *   比如：中国    = zhōng guó
          天安门  = tiān ān mén
          紫禁城  = zǐ jìn chéng
 **/
+ (NSString *)transferMandarinToPinyin:(NSString *)originalStr {
    CFStringRef originalStrRef = (__bridge_retained CFStringRef)originalStr;
    CFMutableStringRef string = CFStringCreateMutableCopy(NULL, 0, originalStrRef);
    CFStringTransform(string, NULL, kCFStringTransformMandarinLatin, false);
    return (__bridge_transfer NSString *)string;
}

/**
 * 将拼音带上注音（变音）符号的去掉
 *   比如： zhōng guó = zhong guo
           tiān ān mén = tian an men
           zǐ jìn chéng = zi jin cheng
 **/
+ (NSString *)stripPinyinDiacritics:(NSString *)originalStr {
    CFStringRef originalStrRef = (__bridge_retained CFStringRef)originalStr;
    CFMutableStringRef string = CFStringCreateMutableCopy(NULL, 0, originalStrRef);
    CFStringTransform(string, NULL, kCFStringTransformStripDiacritics, false);
    return (__bridge_transfer NSString *)string;
}

/**
 * 检测声调位置
 *   例如：sūn， 对于 ū 就返回1
          céng，对于 é 就返回2
          biě， 对于 ě 就返回3
          zhàn，对于 à 就返回4
 **/
+ (int)detectDiacriticsPosition:(NSString *)originalStr {
    // 所有的拼音列表：https://www.wenku1.com/news/40F4D52AD33EF075.html
    // 这些字母都是没有变音符号的 b, c, d, f, h, j, k, l, m, n, p, q, r, s, t, v, w, x, y, z
    NSArray<NSArray<NSString *> *> *pinyinDiacritics = @[
                          @[ @"ā", @"á", @"ǎ", @"à" ],
                          @[ @"ē", @"é", @"ě", @"è" ],
                          @[ @"ī", @"í", @"ǐ", @"ì" ],
                          @[ @"ō", @"ó", @"ǒ", @"ò" ],
                          @[ @"ū", @"ú", @"ǔ", @"ù" ]
                          ];
    BOOL isBreaking = NO;
    int foundPosition = 0;
    for (int i = 0; i < originalStr.length; i++) {
        NSString *letter = [originalStr substringWithRange:NSMakeRange(i, 1)];
        for (int j = 0; j < pinyinDiacritics.count; j++) {
            foundPosition = 0;
            for (int k = 0; k < pinyinDiacritics[j].count; k++) {
                NSString *toneLetter = pinyinDiacritics[j][k];
                if ([letter isEqualToString:toneLetter]) {
                    foundPosition = k + 1;
                    isBreaking = YES;
                    break;
                }
            }
            if (isBreaking) {
                break;
            }
        }
        if (isBreaking) {
            break;
        }
    }
    return foundPosition;
}