kc3-lang/libiconv/lib/johab_hangul.h

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  Date : 2021-06-06T11:51:12
  

  Change the license of the library from LGPL 2.0 to LGPL 2.1.
  

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• lib/johab_hangul.h

• /*
   * Copyright (C) 1999-2001, 2016 Free Software Foundation, Inc.
   * This file is part of the GNU LIBICONV Library.
   *
   * The GNU LIBICONV Library is free software; you can redistribute it
   * and/or modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either version 2.1
   * of the License, or (at your option) any later version.
   *
   * The GNU LIBICONV Library is distributed in the hope that it will be
   * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
   * If not, see <https://www.gnu.org/licenses/>.
   */
  
  /*
   * JOHAB Hangul
   *
   * Ken Lunde writes in his "CJKV Information Processing" book, p. 114:
   * "Hangul can be composed of two or three jamo (some jamo are considered
   *  compound). Johab uses 19 initial jamo (consonants), 21 medial jamo (vowels)
   *  and 27 final jamo (consonants; 28 when you include the "fill" character
   *  for Hangul containing only two jamo). Multiplying these numbers results in
   *  11172."
   *
   * Structure of the Johab encoding (see p. 181-184):
   *   bit 15 = 1
   *   bit 14..10 = initial jamo, only 19+1 out of 32 possible values are used
   *   bit 9..5 = medial jamo, only 21+1 out of 32 possible values are used
   *   bit 4..0 = final jamo, only 27+1 out of 32 possible values are used
   * 
   * Structure of the Unicode encoding:
   * grep '^0x\([8-C]...\|D[0-7]..\)' unicode.org-mappings/EASTASIA/KSC/JOHAB.TXT
   * You see that all characters there are marked "HANGUL LETTER" or "HANGUL
   * SYLLABLE". If you eliminate the "HANGUL LETTER"s, the table is sorted
   * in ascending order according to Johab encoding and according to the Unicode
   * encoding. Now look a little more carefully, and you see that the following
   * formula holds:
   *     unicode == 0xAC00
   *                + 21 * 28 * (jamo_initial_index[(johab >> 10) & 31] - 1)
   *                + 28 * (jamo_medial_index[(johab >> 5) & 31] - 1)
   *                + jamo_final_index[johab & 31]
   * where the index tables are defined as below.
   */
  
  /* Tables mapping 5-bit groups to jamo letters. */
  /* Note that Jamo XX = UHC 0xA4A0+XX = Unicode 0x3130+XX */
  #define NONE 0xfd
  #define FILL 0xff
  static const unsigned char jamo_initial[32] = {
    NONE, FILL, 0x01, 0x02, 0x04, 0x07, 0x08, 0x09,
    0x11, 0x12, 0x13, 0x15, 0x16, 0x17, 0x18, 0x19,
    0x1a, 0x1b, 0x1c, 0x1d, 0x1e, NONE, NONE, NONE,
    NONE, NONE, NONE, NONE, NONE, NONE, NONE, NONE,
  };
  static const unsigned char jamo_medial[32] = {
    NONE, NONE, FILL, 0x1f, 0x20, 0x21, 0x22, 0x23,
    NONE, NONE, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29,
    NONE, NONE, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
    NONE, NONE, 0x30, 0x31, 0x32, 0x33, NONE, NONE,
  };
  static const unsigned char jamo_final[32] = {
    NONE, FILL, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
    0x07, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11, NONE, 0x12, 0x14, 0x15, 0x16, 0x17,
    0x18, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, NONE, NONE,
  };
  /* Same as jamo_final, except that it excludes characters already
     contained in jamo_initial. 11 characters instead of 27. */
  static const unsigned char jamo_final_notinitial[32] = {
    NONE, NONE, NONE, NONE, 0x03, NONE, 0x05, 0x06,
    NONE, NONE, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, NONE, NONE, NONE, 0x14, NONE, NONE, NONE,
    NONE, NONE, NONE, NONE, NONE, NONE, NONE, NONE,
  };
  
  /* Tables mapping 5-bit groups to packed indices. */
  #define none -1
  #define fill 0
  static const signed char jamo_initial_index[32] = {
    none, fill, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
    0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
    0x0f, 0x10, 0x11, 0x12, 0x13, none, none, none,
    none, none, none, none, none, none, none, none,
  };
  static const signed char jamo_medial_index[32] = {
    none, none, fill, 0x01, 0x02, 0x03, 0x04, 0x05,
    none, none, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
    none, none, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
    none, none, 0x12, 0x13, 0x14, 0x15, none, none,
  };
  static const signed char jamo_final_index[32] = {
    none, fill, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
    0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
    0x0f, 0x10, none, 0x11, 0x12, 0x13, 0x14, 0x15,
    0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, none, none,
  };
  
  static int
  johab_hangul_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
  {
    unsigned char c1 = s[0];
    if ((c1 >= 0x84 && c1 <= 0xd3)) {
      if (n >= 2) {
        unsigned char c2 = s[1];
        if ((c2 >= 0x41 && c2 < 0x7f) || (c2 >= 0x81 && c2 < 0xff)) {
          unsigned int johab = (c1 << 8) | c2;
          unsigned int bitspart1 = (johab >> 10) & 31;
          unsigned int bitspart2 = (johab >> 5) & 31;
          unsigned int bitspart3 = johab & 31;
          int index1 = jamo_initial_index[bitspart1];
          int index2 = jamo_medial_index[bitspart2];
          int index3 = jamo_final_index[bitspart3];
          /* Exclude "none" values. */
          if (index1 >= 0 && index2 >= 0 && index3 >= 0) {
            /* Deal with "fill" values in initial or medial position. */
            if (index1 == fill) {
              if (index2 == fill) {
                unsigned char jamo3 = jamo_final_notinitial[bitspart3];
                if (jamo3 != NONE) {
                  *pwc = (ucs4_t) 0x3130 + jamo3;
                  return 2;
                }
              } else if (index3 == fill) {
                unsigned char jamo2 = jamo_medial[bitspart2];
                if (jamo2 != NONE && jamo2 != FILL) {
                  *pwc = (ucs4_t) 0x3130 + jamo2;
                  return 2;
                }
              }
              /* Syllables composed only of medial and final don't exist. */
            } else if (index2 == fill) {
              if (index3 == fill) {
                unsigned char jamo1 = jamo_initial[bitspart1];
                if (jamo1 != NONE && jamo1 != FILL) {
                  *pwc = (ucs4_t) 0x3130 + jamo1;
                  return 2;
                }
              }
              /* Syllables composed only of initial and final don't exist. */
            } else {
               /* index1 and index2 are not fill, but index3 may be fill. */
               /* Nothing more to exclude. All 11172 code points are valid. */
               *pwc = 0xac00 + ((index1 - 1) * 21 + (index2 - 1)) * 28 + index3;
               return 2;
            }
          }
        }
        return RET_ILSEQ;
      }
      return RET_TOOFEW(0);
    }
    return RET_ILSEQ;
  }
  
  /* 51 Jamo: 19 initial, 21 medial, 11 final not initial. */
  static const unsigned short johab_hangul_page31[51] = {
            0x8841, 0x8c41, 0x8444, 0x9041, 0x8446, 0x8447, 0x9441, /*0x30-0x37*/
    0x9841, 0x9c41, 0x844a, 0x844b, 0x844c, 0x844d, 0x844e, 0x844f, /*0x38-0x3f*/
    0x8450, 0xa041, 0xa441, 0xa841, 0x8454, 0xac41, 0xb041, 0xb441, /*0x40-0x47*/
    0xb841, 0xbc41, 0xc041, 0xc441, 0xc841, 0xcc41, 0xd041, 0x8461, /*0x48-0x4f*/
    0x8481, 0x84a1, 0x84c1, 0x84e1, 0x8541, 0x8561, 0x8581, 0x85a1, /*0x50-0x57*/
    0x85c1, 0x85e1, 0x8641, 0x8661, 0x8681, 0x86a1, 0x86c1, 0x86e1, /*0x58-0x5f*/
    0x8741, 0x8761, 0x8781, 0x87a1,                                 /*0x60-0x67*/
  };
  
  /* Tables mapping packed indices to 5-bit groups. */
  /* index1+1 = jamo_initial_index[bitspart1]  <==>
     bitspart1 = jamo_initial_index_inverse[index1] */
  static const char jamo_initial_index_inverse[19] = {
                0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11, 0x12, 0x13, 0x14,
  };
  /* index2+1 = jamo_medial_index[bitspart2]  <==>
     bitspart2 = jamo_medial_index_inverse[index2] */
  static const char jamo_medial_index_inverse[21] = {
                      0x03, 0x04, 0x05, 0x06, 0x07,
                0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
                0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
                0x1a, 0x1b, 0x1c, 0x1d,
  };
  /* index3 = jamo_final_index[bitspart3]  <==>
     bitspart3 = jamo_final_index_inverse[index3] */
  static const char jamo_final_index_inverse[28] = {
          0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11,       0x13, 0x14, 0x15, 0x16, 0x17,
    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d,
  };
  
  static int
  johab_hangul_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, size_t n)
  {
    if (n >= 2) {
      if (wc >= 0x3131 && wc < 0x3164) {
        unsigned short c = johab_hangul_page31[wc-0x3131];
        r[0] = (c >> 8); r[1] = (c & 0xff);
        return 2;
      } else if (wc >= 0xac00 && wc < 0xd7a4) {
        unsigned int index1;
        unsigned int index2;
        unsigned int index3;
        unsigned short c;
        unsigned int tmp = wc - 0xac00;
        index3 = tmp % 28; tmp = tmp / 28;
        index2 = tmp % 21; tmp = tmp / 21;
        index1 = tmp;
        c = (((((1 << 5)
                | jamo_initial_index_inverse[index1]) << 5)
              | jamo_medial_index_inverse[index2]) << 5)
            | jamo_final_index_inverse[index3];
        r[0] = (c >> 8); r[1] = (c & 0xff);
        return 2;
      }
      return RET_ILUNI;
    }
    return RET_TOOSMALL;
  }
  
  /*
   * Decomposition of JOHAB Hangul in one to three Johab Jamo elements.
   */
  
  /* Decompose wc into r[0..2], and return the number of resulting Jamo elements.
     Return RET_ILUNI if decomposition is not possible. */
  
  static int johab_hangul_decompose (conv_t conv, ucs4_t* r, ucs4_t wc)
  {
    unsigned char buf[2];
    int ret = johab_hangul_wctomb(conv,buf,wc,2);
    if (ret != RET_ILUNI) {
      unsigned int hangul = (buf[0] << 8) | buf[1];
      unsigned char jamo1 = jamo_initial[(hangul >> 10) & 31];
      unsigned char jamo2 = jamo_medial[(hangul >> 5) & 31];
      unsigned char jamo3 = jamo_final[hangul & 31];
      if ((hangul >> 15) != 1) abort();
      if (jamo1 != NONE && jamo2 != NONE && jamo3 != NONE) {
        /* They are not all three == FILL because that would correspond to
           johab = 0x8441, which doesn't exist. */
        ucs4_t* p = r;
        if (jamo1 != FILL)
          *p++ = 0x3130 + jamo1;
        if (jamo2 != FILL)
          *p++ = 0x3130 + jamo2;
        if (jamo3 != FILL)
          *p++ = 0x3130 + jamo3;
        return p-r;
      }
    }
    return RET_ILUNI;
  }
  
  #undef fill
  #undef none
  #undef FILL
  #undef NONE
  

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