#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <locale.h>
#include "mbctype.h"

/* for some conversions, we use the __count field as a place to store a state value */
#define __state __count

extern char __lc_ctype[12];

int
_DEFUN (_wctomb_r, (r, s, wchar, state),
        struct _reent *r     _AND 
        char          *s     _AND
        wchar_t        wchar _AND
        mbstate_t     *state)
{
  if (strlen (__lc_ctype) <= 1)
    { /* fall-through */ }
  else if (!strcmp (__lc_ctype, "C-UTF-8"))
    {
      if (s == NULL)
        return 0; /* UTF-8 encoding is not state-dependent */

      if (wchar <= 0x7f)
        {
          *s = wchar;
          return 1;
        }
      else if (wchar >= 0x80 && wchar <= 0x7ff)
        {
          *s++ = 0xc0 | ((wchar & 0x7c0) >> 6);
          *s   = 0x80 |  (wchar &  0x3f);
          return 2;
        }
      else if (wchar >= 0x800 && wchar <= 0xffff)
        {
          /* UTF-16 surrogates -- must not occur in normal UCS-4 data */
          if (wchar >= 0xd800 && wchar <= 0xdfff)
            return -1;

          *s++ = 0xe0 | ((wchar & 0xf000) >> 12);
          *s++ = 0x80 | ((wchar &  0xfc0) >> 6);
          *s   = 0x80 |  (wchar &   0x3f);
          return 3;
        }
      else if (wchar >= 0x10000 && wchar <= 0x1fffff)
        {
          *s++ = 0xf0 | ((wchar & 0x1c0000) >> 18);
          *s++ = 0x80 | ((wchar &  0x3f000) >> 12);
          *s++ = 0x80 | ((wchar &    0xfc0) >> 6);
          *s   = 0x80 |  (wchar &     0x3f);
          return 4;
        }
      else if (wchar >= 0x200000 && wchar <= 0x3ffffff)
        {
          *s++ = 0xf8 | ((wchar & 0x3000000) >> 24);
          *s++ = 0x80 | ((wchar &  0xfc0000) >> 18);
          *s++ = 0x80 | ((wchar &   0x3f000) >> 12);
          *s++ = 0x80 | ((wchar &     0xfc0) >> 6);
          *s   = 0x80 |  (wchar &      0x3f);
          return 5;
        }
      else if (wchar >= 0x4000000 && wchar <= 0x7fffffff)
        {
          *s++ = 0xfc | ((wchar & 0x40000000) >> 30);
          *s++ = 0x80 | ((wchar & 0x3f000000) >> 24);
          *s++ = 0x80 | ((wchar &   0xfc0000) >> 18);
          *s++ = 0x80 | ((wchar &    0x3f000) >> 12);
          *s++ = 0x80 | ((wchar &      0xfc0) >> 6);
          *s   = 0x80 |  (wchar &       0x3f);
          return 6;
        }
      else
        return -1;
    }
  else if (!strcmp (__lc_ctype, "C-SJIS"))
    {
      unsigned char char2 = (unsigned char)wchar;
      unsigned char char1 = (unsigned char)(wchar >> 8);

      if (s == NULL)
        return 0;  /* not state-dependent */

      if (char1 != 0x00)
        {
        /* first byte is non-zero..validate multi-byte char */
          if (_issjis1(char1) && _issjis2(char2)) 
            {
              *s++ = (char)char1;
              *s = (char)char2;
              return 2;
            }
          else
            return -1;
        }
    }
  else if (!strcmp (__lc_ctype, "C-EUCJP"))
    {
      unsigned char char2 = (unsigned char)wchar;
      unsigned char char1 = (unsigned char)(wchar >> 8);

      if (s == NULL)
        return 0;  /* not state-dependent */

      if (char1 != 0x00)
        {
        /* first byte is non-zero..validate multi-byte char */
          if (_iseucjp (char1) && _iseucjp (char2)) 
            {
              *s++ = (char)char1;
              *s = (char)char2;
              return 2;
            }
          else
            return -1;
        }
    }
  else if (!strcmp (__lc_ctype, "C-JIS"))
    {
      int cnt = 0; 
      unsigned char char2 = (unsigned char)wchar;
      unsigned char char1 = (unsigned char)(wchar >> 8);

      if (s == NULL)
        return 1;  /* state-dependent */

      if (char1 != 0x00)
        {
        /* first byte is non-zero..validate multi-byte char */
          if (_isjis (char1) && _isjis (char2)) 
            {
              if (state->__state == 0)
                {
                  /* must switch from ASCII to JIS state */
                  state->__state = 1;
                  *s++ = ESC_CHAR;
                  *s++ = '$';
                  *s++ = 'B';
                  cnt = 3;
                }
              *s++ = (char)char1;
              *s = (char)char2;
              return cnt + 2;
            }
          else
            return -1;
        }
      else
        {
          if (state->__state != 0)
            {
              /* must switch from JIS to ASCII state */
              state->__state = 0;
              *s++ = ESC_CHAR;
              *s++ = '(';
              *s++ = 'B';
              cnt = 3;
            }
          *s = (char)char2;
          return cnt + 1;
        }
    }

  if (s == NULL)
    return 0;
 
  /* otherwise we are dealing with a single byte character */
  *s = (char) wchar;
  return 1;
}