text: /* Tables for conversion to and from ISO-IR-165.
     converting from UCS using gaps.
     Copyright (C) 2000-2020 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
     Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000.
  
     The GNU C 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 C 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 C Library; if not, see
     <https://www.gnu.org/licenses/>.  */
  
  #ifndef _ISO_IR_165_H
  #define _ISO_IR_165_H	1
  
  #include <gconv.h>
  #include <stdint.h>
  
  struct gap
  {
    uint16_t start;
    uint16_t end;
    int32_t idx;
  };
  
  /* Table for ISO-IR-165 (CCITT Chinese) to UCS4 conversion.  */
  #define ISOIR165_FROMSIZE	0x2284
  extern const uint16_t __isoir165_to_tab[ISOIR165_FROMSIZE];
  
  
  /* XXX If we at some point need an offset value to decode the byte
     sequences another parameter can be added.  */
  static inline uint32_t
  __attribute ((always_inline))
  isoir165_to_ucs4 (const unsigned char **s, size_t avail)
  {
    unsigned char ch = *(*s);
    unsigned char ch2;
    uint32_t res;
  
    if (ch <= 0x20 || ch >= 0x7f)
      return __UNKNOWN_10646_CHAR;
  
    if (avail < 2)
      return 0;
  
    ch2 = (*s)[1];
    if (ch2 <= 0x20 || ch2 >= 0x7f)
      return __UNKNOWN_10646_CHAR;
  
    res = __isoir165_to_tab[(ch - 0x21) * 94 + (ch2 - 0x21)];
    if (res == 0)
      return __UNKNOWN_10646_CHAR;
  
    *s += 2;
    return res;
  }
  
  
  /* Tables for ISO-IR-165 (CCITT Chinese) from UCS4 conversion.  */
  extern const struct gap __isoir165_from_idx[];
  extern const char __isoir165_from_tab[];
  
  static inline size_t
  __attribute ((always_inline))
  ucs4_to_isoir165 (uint32_t wch, unsigned char *s, size_t avail)
  {
    unsigned int ch = (unsigned int) wch;
    const char *cp;
    const struct gap *rp = __isoir165_from_idx;
  
    if (ch > 0xffe5)
      /* This is an illegal character.  */
      return __UNKNOWN_10646_CHAR;
  
    while (ch > rp->end)
      ++rp;
    if (ch < rp->start)
      /* This is an illegal character.  */
      return __UNKNOWN_10646_CHAR;
  
    /* The two bytes following the index given in this record give the
       encoding in ISO-IR-165.  Unless the bytes are zero.  */
    cp = &__isoir165_from_tab[(ch + rp->idx) * 2];
    if (*cp == '\0')
      /* This is an illegal character.  */
      return __UNKNOWN_10646_CHAR;
  
    if (avail < 2)
      return 0;
  
    s[0] = cp[0];
    s[1] = cp[1];
  
    return 2;
  }
  
  #endif	/* iso-ir-165.h */
  