1  /* Access functions for CNS 11643, plane 2 handling.
       2     Copyright (C) 1998-2023 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  #include <stdint.h>
      20  #include <gconv.h>
      21  
      22  /* Table for CNS 11643, plane 2 to UCS4 conversion.  */
      23  extern const uint16_t __cns11643l2_to_ucs4_tab[];
      24  
      25  
      26  static inline uint32_t
      27  __attribute ((always_inline))
      28  cns11643l2_to_ucs4 (const unsigned char **s, size_t avail,
      29  		    unsigned char offset)
      30  {
      31    unsigned char ch = *(*s);
      32    unsigned char ch2;
      33    int idx;
      34  
      35    if (ch < offset || (ch - offset) <= 0x20 || (ch - offset) > 0x7d)
      36      return __UNKNOWN_10646_CHAR;
      37  
      38    if (avail < 2)
      39      return 0;
      40  
      41    ch2 = (*s)[1];
      42    if ((ch2 - offset) <= 0x20 || (ch2 - offset) >= 0x7f)
      43      return __UNKNOWN_10646_CHAR;
      44  
      45    idx = (ch - 0x21 - offset) * 94 + (ch2 - 0x21 - offset);
      46    if (idx > 0x1de1)
      47      return __UNKNOWN_10646_CHAR;
      48  
      49    (*s) += 2;
      50  
      51    return __cns11643l2_to_ucs4_tab[idx] ?: ((*s) -= 2, __UNKNOWN_10646_CHAR);
      52  }
      53  
      54  
      55  /* The table which contains the CNS 11643 level 2 mappings.  */
      56  extern const char __cns11643_from_ucs4p0_tab[][3];
      57  
      58  
      59  static inline size_t
      60  __attribute ((always_inline))
      61  ucs4_to_cns11643l2 (uint32_t wch, unsigned char *s, size_t avail)
      62  {
      63    unsigned int ch = (unsigned int) wch;
      64    const char *cp = NULL;
      65  
      66    if (ch >= 0x4e07 && ch <= 0x9fa4)
      67      {
      68        cp = __cns11643_from_ucs4p0_tab[ch - 0x3400];
      69        if (cp[0] == '\2')
      70  	++cp;
      71        else
      72  	cp = NULL;
      73      }
      74  
      75    if (cp == NULL)
      76      return __UNKNOWN_10646_CHAR;
      77  
      78    if (avail < 2)
      79      return 0;
      80  
      81    s[0] = cp[0];
      82    s[1] = cp[1];
      83  
      84    return 2;
      85  }