String string_metaphone(const char *input, int word_len, long max_phonemes,
                        int traditional) {
  unsigned char *word = (unsigned char *)input;

  int w_idx = 0;        /* point in the phonization we're at. */
  int max_buffer_len = 0;    /* maximum length of the destination buffer */

  /*-- Parameter checks --*/
  /* Negative phoneme length is meaningless */

  if (max_phonemes < 0)
    return String();

  /* Empty/null string is meaningless */
  /* Overly paranoid */
  /* always_assert(word != NULL && word[0] != '\0'); */

  if (word == nullptr)
    return String();

  /*-- Allocate memory for our phoned_phrase --*/
  if (max_phonemes == 0) {  /* Assume largest possible */
    max_buffer_len = word_len;
  } else {
    max_buffer_len = max_phonemes;
  }
  StringBuffer buffer(max_buffer_len);

  /*-- The first phoneme has to be processed specially. --*/
  /* Find our first letter */
  for (; !isalpha(Curr_Letter); w_idx++) {
    /* On the off chance we were given nothing but crap... */
    if (Curr_Letter == '\0') {
      return buffer.detach();  /* For testing */
    }
  }

  switch (Curr_Letter) {
    /* AE becomes E */
  case 'A':
    if (Next_Letter == 'E') {
      Phonize('E');
      w_idx += 2;
    }
    /* Remember, preserve vowels at the beginning */
    else {
      Phonize('A');
      w_idx++;
    }
    break;
    /* [GKP]N becomes N */
  case 'G':
  case 'K':
  case 'P':
    if (Next_Letter == 'N') {
      Phonize('N');
      w_idx += 2;
    }
    break;
    /* WH becomes H,
       WR becomes R
       W if followed by a vowel */
  case 'W':
    if (Next_Letter == 'H' ||
      Next_Letter == 'R') {
      Phonize(Next_Letter);
      w_idx += 2;
    } else if (isvowel(Next_Letter)) {
      Phonize('W');
      w_idx += 2;
    }
    /* else ignore */
    break;
    /* X becomes S */
  case 'X':
    Phonize('S');
    w_idx++;
    break;
    /* Vowels are kept */
    /* We did A already
       case 'A':
       case 'a':
     */
  case 'E':
  case 'I':
  case 'O':
  case 'U':
    Phonize(Curr_Letter);
    w_idx++;
    break;
  default:
    /* do nothing */
    break;
  }

  /* On to the metaphoning */
  for (; Curr_Letter != '\0' &&
         (max_phonemes == 0 || Phone_Len < max_phonemes);
       w_idx++) {
    /* How many letters to skip because an eariler encoding handled
     * multiple letters */
    unsigned short int skip_letter = 0;


    /* THOUGHT:  It would be nice if, rather than having things like...
     * well, SCI.  For SCI you encode the S, then have to remember
     * to skip the C.  So the phonome SCI invades both S and C.  It would
     * be better, IMHO, to skip the C from the S part of the encoding.
     * Hell, I'm trying it.
     */

    /* Ignore non-alphas */
    if (!isalpha(Curr_Letter))
      continue;

    /* Drop duplicates, except CC */
    if (Curr_Letter == Prev_Letter &&
      Curr_Letter != 'C')
      continue;

    switch (Curr_Letter) {
      /* B -> B unless in MB */
    case 'B':
      if (Prev_Letter != 'M')
        Phonize('B');
      break;
      /* 'sh' if -CIA- or -CH, but not SCH, except SCHW.
       * (SCHW is handled in S)
       *  S if -CI-, -CE- or -CY-
       *  dropped if -SCI-, SCE-, -SCY- (handed in S)
       *  else K
       */
    case 'C':
      if (MAKESOFT(Next_Letter)) {  /* C[IEY] */
        if (After_Next_Letter == 'A' &&
          Next_Letter == 'I') {  /* CIA */
          Phonize(SH);
        }
        /* SC[IEY] */
        else if (Prev_Letter == 'S') {
          /* Dropped */
        } else {
          Phonize('S');
        }
      } else if (Next_Letter == 'H') {
        if ((!traditional) && (After_Next_Letter == 'R' ||
                               Prev_Letter == 'S')) {  /* Christ, School */
          Phonize('K');
        } else {
          Phonize(SH);
        }
        skip_letter++;
      } else {
        Phonize('K');
      }
      break;
      /* J if in -DGE-, -DGI- or -DGY-
       * else T
       */
    case 'D':
      if (Next_Letter == 'G' && MAKESOFT(After_Next_Letter)) {
        Phonize('J');
        skip_letter++;
      } else
        Phonize('T');
      break;
      /* F if in -GH and not B--GH, D--GH, -H--GH, -H---GH
       * else dropped if -GNED, -GN,
       * else dropped if -DGE-, -DGI- or -DGY- (handled in D)
       * else J if in -GE-, -GI, -GY and not GG
       * else K
       */
    case 'G':
      if (Next_Letter == 'H') {
        if (!(NOGHTOF(Look_Back_Letter(3)) || Look_Back_Letter(4) == 'H')) {
          Phonize('F');
          skip_letter++;
        } else {
          /* silent */
        }
      } else if (Next_Letter == 'N') {
        if (Isbreak(After_Next_Letter) ||
            (After_Next_Letter == 'E' && Look_Ahead_Letter(3) == 'D')) {
          /* dropped */
        } else
          Phonize('K');
      } else if (MAKESOFT(Next_Letter) && Prev_Letter != 'G') {
        Phonize('J');
      } else {
        Phonize('K');
      }
      break;
      /* H if before a vowel and not after C,G,P,S,T */
    case 'H':
      if (isvowel(Next_Letter) && !AFFECTH(Prev_Letter))
        Phonize('H');
      break;
      /* dropped if after C
       * else K
       */
    case 'K':
      if (Prev_Letter != 'C')
        Phonize('K');
      break;
      /* F if before H
       * else P
       */
    case 'P':
      if (Next_Letter == 'H') {
        Phonize('F');
      } else {
        Phonize('P');
      }
      break;
      /* K
       */
    case 'Q':
      Phonize('K');
      break;
      /* 'sh' in -SH-, -SIO- or -SIA- or -SCHW-
       * else S
       */
    case 'S':
      if (Next_Letter == 'I' &&
          (After_Next_Letter == 'O' || After_Next_Letter == 'A')) {
        Phonize(SH);
      } else if (Next_Letter == 'H') {
        Phonize(SH);
        skip_letter++;
      } else if ((!traditional) &&
                 (Next_Letter == 'C' && Look_Ahead_Letter(2) == 'H' &&
                  Look_Ahead_Letter(3) == 'W')) {
        Phonize(SH);
        skip_letter += 2;
      } else {
        Phonize('S');
      }
      break;
      /* 'sh' in -TIA- or -TIO-
       * else 'th' before H
       * else T
       */
    case 'T':
      if (Next_Letter == 'I' &&
        (After_Next_Letter == 'O' || After_Next_Letter == 'A')) {
        Phonize(SH);
      } else if (Next_Letter == 'H') {
        Phonize(TH);
        skip_letter++;
      } else {
        Phonize('T');
      }
      break;
      /* F */
    case 'V':
      Phonize('F');
      break;
      /* W before a vowel, else dropped */
    case 'W':
      if (isvowel(Next_Letter))
        Phonize('W');
      break;
      /* KS */
    case 'X':
      Phonize('K');
      Phonize('S');
      break;
      /* Y if followed by a vowel */
    case 'Y':
      if (isvowel(Next_Letter))
        Phonize('Y');
      break;
      /* S */
    case 'Z':
      Phonize('S');
      break;
      /* No transformation */
    case 'F':
    case 'J':
    case 'L':
    case 'M':
    case 'N':
    case 'R':
      Phonize(Curr_Letter);
      break;
    default:
      /* nothing */
      break;
    } /* END SWITCH */

    w_idx += skip_letter;
  } /* END FOR */

  return buffer.detach();
}
Unknown