1  /* Access functions for JISX0208 conversion.
       2     Copyright (C) 1997-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _JIS0208_H
      20  #define _JIS0208_H	1
      21  
      22  #include <gconv.h>
      23  #include <stdint.h>
      24  
      25  /* Struct for table with indices in UCS mapping table.  */
      26  struct jisx0208_ucs_idx
      27  {
      28    uint16_t start;
      29    uint16_t end;
      30    uint16_t idx;
      31  };
      32  
      33  
      34  /* Conversion table.  */
      35  extern const uint16_t __jis0208_to_ucs[];
      36  
      37  #define JIS0208_LAT1_MIN 0xa2
      38  #define JIS0208_LAT1_MAX 0xf7
      39  extern const char __jisx0208_from_ucs4_lat1[JIS0208_LAT1_MAX + 1
      40  					    - JIS0208_LAT1_MIN][2];
      41  extern const char __jisx0208_from_ucs4_greek[0xc1][2];
      42  extern const struct jisx0208_ucs_idx __jisx0208_from_ucs_idx[];
      43  extern const char __jisx0208_from_ucs_tab[][2];
      44  
      45  
      46  static inline uint32_t
      47  __attribute ((always_inline))
      48  jisx0208_to_ucs4 (const unsigned char **s, size_t avail, unsigned char offset)
      49  {
      50    unsigned char ch = *(*s);
      51    unsigned char ch2;
      52    int idx;
      53  
      54    if (ch < offset || (ch - offset) <= 0x20)
      55      return __UNKNOWN_10646_CHAR;
      56  
      57    if (avail < 2)
      58      return 0;
      59  
      60    ch2 = (*s)[1];
      61    if (ch2 < offset || (ch2 - offset) <= 0x20 || (ch2 - offset) >= 0x7f)
      62      return __UNKNOWN_10646_CHAR;
      63  
      64    idx = (ch - 0x21 - offset) * 94 + (ch2 - 0x21 - offset);
      65    if (idx >= 0x1e80)
      66      return __UNKNOWN_10646_CHAR;
      67  
      68    (*s) += 2;
      69  
      70    return __jis0208_to_ucs[idx] ?: ((*s) -= 2, __UNKNOWN_10646_CHAR);
      71  }
      72  
      73  
      74  static inline size_t
      75  __attribute ((always_inline))
      76  ucs4_to_jisx0208 (uint32_t wch, unsigned char *s, size_t avail)
      77  {
      78    unsigned int ch = (unsigned int) wch;
      79    const char *cp;
      80  
      81    if (avail < 2)
      82      return 0;
      83  
      84    if (ch >= JIS0208_LAT1_MIN && ch <= JIS0208_LAT1_MAX)
      85      cp = __jisx0208_from_ucs4_lat1[ch - JIS0208_LAT1_MIN];
      86    else if (ch >= 0x391 && ch <= 0x451)
      87      cp = __jisx0208_from_ucs4_greek[ch - 0x391];
      88    else
      89      {
      90        const struct jisx0208_ucs_idx *rp = __jisx0208_from_ucs_idx;
      91  
      92        if (ch >= 0xffff)
      93  	return __UNKNOWN_10646_CHAR;
      94        while (ch > rp->end)
      95  	++rp;
      96        if (ch >= rp->start)
      97  	cp = __jisx0208_from_ucs_tab[rp->idx + ch - rp->start];
      98        else
      99  	return __UNKNOWN_10646_CHAR;
     100      }
     101  
     102    if (cp[0] == '\0')
     103      return __UNKNOWN_10646_CHAR;
     104  
     105    s[0] = cp[0];
     106    s[1] = cp[1];
     107  
     108    return 2;
     109  }
     110  
     111  #endif /* jis0208.h */