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

int (*__mbtowc) (struct _reent *, wchar_t *, const char *, size_t,
		 const char *, mbstate_t *)
   = __ascii_mbtowc;

int
_DEFUN (_mbtowc_r, (r, pwc, s, n, state),
        struct _reent *r   _AND
        wchar_t       *pwc _AND 
        const char    *s   _AND        
        size_t         n   _AND
        mbstate_t      *state)
{
  return __mbtowc (r, pwc, s, n, __locale_charset (), state);
}

int
_DEFUN (__ascii_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;

  if (pwc == NULL)
    pwc = &dummy;

  if (s == NULL)
    return 0;

  if (n == 0)
    return -2;

  *pwc = (wchar_t)*t;
  
  if (*t == '\0')
    return 0;

  return 1;
}

#ifdef _MB_CAPABLE
typedef enum { ESCAPE, DOLLAR, BRACKET, AT, B, J, 
               NUL, JIS_CHAR, OTHER, JIS_C_NUM } JIS_CHAR_TYPE;
typedef enum { ASCII, JIS, A_ESC, A_ESC_DL, JIS_1, J_ESC, J_ESC_BR,
               INV, JIS_S_NUM } JIS_STATE; 
typedef enum { COPY_A, COPY_J1, COPY_J2, MAKE_A, NOOP, EMPTY, ERROR } JIS_ACTION;

/************************************************************************************** 
 * state/action tables for processing JIS encoding
 * Where possible, switches to JIS are grouped with proceding JIS characters and switches
 * to ASCII are grouped with preceding JIS characters.  Thus, maximum returned length
 * is 2 (switch to JIS) + 2 (JIS characters) + 2 (switch back to ASCII) = 6.
 *************************************************************************************/

static JIS_STATE JIS_state_table[JIS_S_NUM][JIS_C_NUM] = {
/*              ESCAPE   DOLLAR    BRACKET   AT       B       J        NUL      JIS_CHAR  OTHER */
/* ASCII */   { A_ESC,   ASCII,    ASCII,    ASCII,   ASCII,  ASCII,   ASCII,   ASCII,    ASCII },
/* JIS */     { J_ESC,   JIS_1,    JIS_1,    JIS_1,   JIS_1,  JIS_1,   INV,     JIS_1,    INV },
/* A_ESC */   { ASCII,   A_ESC_DL, ASCII,    ASCII,   ASCII,  ASCII,   ASCII,   ASCII,    ASCII },
/* A_ESC_DL */{ ASCII,   ASCII,    ASCII,    JIS,     JIS,    ASCII,   ASCII,   ASCII,    ASCII }, 
/* JIS_1 */   { INV,     JIS,      JIS,      JIS,     JIS,    JIS,     INV,     JIS,      INV },
/* J_ESC */   { INV,     INV,      J_ESC_BR, INV,     INV,    INV,     INV,     INV,      INV },
/* J_ESC_BR */{ INV,     INV,      INV,      INV,     ASCII,  ASCII,   INV,     INV,      INV },
};

static JIS_ACTION JIS_action_table[JIS_S_NUM][JIS_C_NUM] = {
/*              ESCAPE   DOLLAR    BRACKET   AT       B        J        NUL      JIS_CHAR  OTHER */
/* ASCII */   { NOOP,    COPY_A,   COPY_A,   COPY_A,  COPY_A,  COPY_A,  EMPTY,   COPY_A,  COPY_A},
/* JIS */     { NOOP,    COPY_J1,  COPY_J1,  COPY_J1, COPY_J1, COPY_J1, ERROR,   COPY_J1, ERROR },
/* A_ESC */   { COPY_A,  NOOP,     COPY_A,   COPY_A,  COPY_A,  COPY_A,  COPY_A,  COPY_A,  COPY_A},
/* A_ESC_DL */{ COPY_A,  COPY_A,   COPY_A,   NOOP,    NOOP,    COPY_A,  COPY_A,  COPY_A,  COPY_A},
/* JIS_1 */   { ERROR,   COPY_J2,  COPY_J2,  COPY_J2, COPY_J2, COPY_J2, ERROR,   COPY_J2, ERROR },
/* J_ESC */   { ERROR,   ERROR,    NOOP,     ERROR,   ERROR,   ERROR,   ERROR,   ERROR,   ERROR },
/* J_ESC_BR */{ ERROR,   ERROR,    ERROR,    ERROR,   MAKE_A,  MAKE_A,  ERROR,   ERROR,   ERROR },
};

/* we override the mbstate_t __count field for more complex encodings and use it store a state value */
#define __state __count

#ifdef _MB_EXTENDED_CHARSETS_ISO
int
_DEFUN (__iso_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;

  if (pwc == NULL)
    pwc = &dummy;

  if (s == NULL)
    return 0;

  if (n == 0)
    return -2;

  if (*t >= 0xa0)
    {
      int iso_idx = __iso_8859_index (charset + 9);
      if (iso_idx >= 0)
	{
	  *pwc = __iso_8859_conv[iso_idx][*t - 0xa0];
	  if (*pwc == 0) /* Invalid character */
	    {
	      r->_errno = EILSEQ;
	      return -1;
	    }
	  return 1;
	}
    }

  *pwc = (wchar_t) *t;
  
  if (*t == '\0')
    return 0;

  return 1;
}
#endif /* _MB_EXTENDED_CHARSETS_ISO */

#ifdef _MB_EXTENDED_CHARSETS_WINDOWS
int
_DEFUN (__cp_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;

  if (pwc == NULL)
    pwc = &dummy;

  if (s == NULL)
    return 0;

  if (n == 0)
    return -2;

  if (*t >= 0x80)
    {
      int cp_idx = __cp_index (charset + 2);
      if (cp_idx >= 0)
	{
	  *pwc = __cp_conv[cp_idx][*t - 0x80];
	  if (*pwc == 0) /* Invalid character */
	    {
	      r->_errno = EILSEQ;
	      return -1;
	    }
	  return 1;
	}
    }

  *pwc = (wchar_t)*t;
  
  if (*t == '\0')
    return 0;

  return 1;
}
#endif /* _MB_EXTENDED_CHARSETS_WINDOWS */

int
_DEFUN (__utf8_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;
  int ch;
  int i = 0;

  if (pwc == NULL)
    pwc = &dummy;

  if (s == NULL)
    return 0;

  if (n == 0)
    return -2;

  if (state->__count == 4)
    {
      /* Create the second half of the surrogate pair.  For a description
	 see the comment below. */
      wint_t tmp = (wchar_t)((state->__value.__wchb[0] & 0x07) << 18)
	|   (wchar_t)((state->__value.__wchb[1] & 0x3f) << 12)
	|   (wchar_t)((state->__value.__wchb[2] & 0x3f) << 6)
	|   (wchar_t)(state->__value.__wchb[3] & 0x3f);
      state->__count = 0;
      *pwc = 0xdc00 | ((tmp - 0x10000) & 0x3ff);
      return 2;
    }
  if (state->__count == 0)
    ch = t[i++];
  else
    {
      if (n < (size_t)-1)
	++n;
      ch = state->__value.__wchb[0];
    }

  if (ch == '\0')
    {
      *pwc = 0;
      state->__count = 0;
      return 0; /* s points to the null character */
    }

  if (ch >= 0x0 && ch <= 0x7f)
    {
      /* single-byte sequence */
      state->__count = 0;
      *pwc = ch;
      return 1;
    }
  if (ch >= 0xc0 && ch <= 0xdf)
    {
      /* two-byte sequence */
      state->__value.__wchb[0] = ch;
      state->__count = 1;
      if (n < 2)
	return -2;
      ch = t[i++];
      if (ch < 0x80 || ch > 0xbf)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      if (state->__value.__wchb[0] < 0xc2)
	{
	  /* overlong UTF-8 sequence */
	  r->_errno = EILSEQ;
	  return -1;
	}
      state->__count = 0;
      *pwc = (wchar_t)((state->__value.__wchb[0] & 0x1f) << 6)
	|    (wchar_t)(ch & 0x3f);
      return i;
    }
  if (ch >= 0xe0 && ch <= 0xef)
    {
      /* three-byte sequence */
      wchar_t tmp;
      state->__value.__wchb[0] = ch;
      if (state->__count == 0)
	state->__count = 1;
      else if (n < (size_t)-1)
	++n;
      if (n < 2)
	return -2;
      ch = (state->__count == 1) ? t[i++] : state->__value.__wchb[1];
      if (state->__value.__wchb[0] == 0xe0 && ch < 0xa0)
	{
	  /* overlong UTF-8 sequence */
	  r->_errno = EILSEQ;
	  return -1;
	}
      if (ch < 0x80 || ch > 0xbf)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      state->__value.__wchb[1] = ch;
      state->__count = 2;
      if (n < 3)
	return -2;
      ch = t[i++];
      if (ch < 0x80 || ch > 0xbf)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      state->__count = 0;
      tmp = (wchar_t)((state->__value.__wchb[0] & 0x0f) << 12)
	|    (wchar_t)((state->__value.__wchb[1] & 0x3f) << 6)
	|     (wchar_t)(ch & 0x3f);
    
      if (tmp >= 0xd800 && tmp <= 0xdfff)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      *pwc = tmp;
      return i;
    }
  if (ch >= 0xf0 && ch <= 0xf7)
    {
      /* four-byte sequence */
      wint_t tmp;
      state->__value.__wchb[0] = ch;
      if (state->__count == 0)
	state->__count = 1;
      else if (n < (size_t)-1)
	++n;
      if (n < 2)
	return -2;
      ch = (state->__count == 1) ? t[i++] : state->__value.__wchb[1];
      if (state->__value.__wchb[0] == 0xf0 && ch < 0x90)
	{
	  /* overlong UTF-8 sequence */
	  r->_errno = EILSEQ;
	  return -1;
	}
      if (ch < 0x80 || ch > 0xbf)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      state->__value.__wchb[1] = ch;
      if (state->__count == 1)
	state->__count = 2;
      else if (n < (size_t)-1)
	++n;
      if (n < 3)
	return -2;
      ch = (state->__count == 2) ? t[i++] : state->__value.__wchb[2];
      if (ch < 0x80 || ch > 0xbf)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      state->__value.__wchb[2] = ch;
      state->__count = 3;
      if (n < 4)
	return -2;
      ch = t[i++];
      if (ch < 0x80 || ch > 0xbf)
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
      tmp = (wint_t)((state->__value.__wchb[0] & 0x07) << 18)
	|   (wint_t)((state->__value.__wchb[1] & 0x3f) << 12)
	|   (wint_t)((state->__value.__wchb[2] & 0x3f) << 6)
	|   (wint_t)(ch & 0x3f);
      if (tmp > 0xffff && sizeof(wchar_t) == 2)
	{
	  /* On systems which have wchar_t being UTF-16 values, the value
	     doesn't fit into a single wchar_t in this case.  So what we
	     do here is to store the state with a special value of __count
	     and return the first half of a surrogate pair.  As return
	     value we choose to return the half of the actual UTF-8 char.
	     The second half is returned in case we recognize the special
	     __count value above. */
	  state->__value.__wchb[3] = ch;
	  state->__count = 4;
	  *pwc = 0xd800 | (((tmp - 0x10000) >> 10) & 0x3ff);
	  return 2;
	}
      *pwc = tmp;
      state->__count = 0;
      return i;
    }

  r->_errno = EILSEQ;
  return -1;
}

/* Cygwin defines its own doublebyte charset conversion functions 
   because the underlying OS requires wchar_t == UTF-16. */
#ifndef  __CYGWIN__
int
_DEFUN (__sjis_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;
  int ch;
  int i = 0;

  if (pwc == NULL)
    pwc = &dummy;

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

  if (n == 0)
    return -2;

  ch = t[i++];
  if (state->__count == 0)
    {
      if (_issjis1 (ch))
	{
	  state->__value.__wchb[0] = ch;
	  state->__count = 1;
	  if (n <= 1)
	    return -2;
	  ch = t[i++];
	}
    }
  if (state->__count == 1)
    {
      if (_issjis2 (ch))
	{
	  *pwc = (((wchar_t)state->__value.__wchb[0]) << 8) + (wchar_t)ch;
	  state->__count = 0;
	  return i;
	}
      else  
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
    }

  *pwc = (wchar_t)*t;
  
  if (*t == '\0')
    return 0;

  return 1;
}

int
_DEFUN (__eucjp_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;
  int ch;
  int i = 0;

  if (pwc == NULL)
    pwc = &dummy;

  if (s == NULL)
    return 0;

  if (n == 0)
    return -2;

  ch = t[i++];
  if (state->__count == 0)
    {
      if (_iseucjp (ch))
	{
	  state->__value.__wchb[0] = ch;
	  state->__count = 1;
	  if (n <= 1)
	    return -2;
	  ch = t[i++];
	}
    }
  if (state->__count == 1)
    {
      if (_iseucjp (ch))
	{
	  *pwc = (((wchar_t)state->__value.__wchb[0]) << 8) + (wchar_t)ch;
	  state->__count = 0;
	  return i;
	}
      else
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
    }

  *pwc = (wchar_t)*t;
  
  if (*t == '\0')
    return 0;

  return 1;
}

int
_DEFUN (__jis_mbtowc, (r, pwc, s, n, charset, state),
        struct _reent *r       _AND
        wchar_t       *pwc     _AND 
        const char    *s       _AND        
        size_t         n       _AND
	const char    *charset _AND
        mbstate_t      *state)
{
  wchar_t dummy;
  unsigned char *t = (unsigned char *)s;
  JIS_STATE curr_state;
  JIS_ACTION action;
  JIS_CHAR_TYPE ch;
  unsigned char *ptr;
  unsigned int i;
  int curr_ch;

  if (pwc == NULL)
    pwc = &dummy;

  if (s == NULL)
    {
      state->__state = ASCII;
      return 1;  /* state-dependent */
    }

  if (n == 0)
    return -2;

  curr_state = state->__state;
  ptr = t;

  for (i = 0; i < n; ++i)
    {
      curr_ch = t[i];
      switch (curr_ch)
	{
	case ESC_CHAR:
	  ch = ESCAPE;
	  break;
	case '$':
	  ch = DOLLAR;
	  break;
	case '@':
	  ch = AT;
	  break;
	case '(':
	  ch = BRACKET;
	  break;
	case 'B':
	  ch = B;
	  break;
	case 'J':
	  ch = J;
	  break;
	case '\0':
	  ch = NUL;
	  break;
	default:
	  if (_isjis (curr_ch))
	    ch = JIS_CHAR;
	  else
	    ch = OTHER;
	}

      action = JIS_action_table[curr_state][ch];
      curr_state = JIS_state_table[curr_state][ch];
    
      switch (action)
	{
	case NOOP:
	  break;
	case EMPTY:
	  state->__state = ASCII;
	  *pwc = (wchar_t)0;
	  return 0;
	case COPY_A:
	  state->__state = ASCII;
	  *pwc = (wchar_t)*ptr;
	  return (i + 1);
	case COPY_J1:
	  state->__value.__wchb[0] = t[i];
	  break;
	case COPY_J2:
	  state->__state = JIS;
	  *pwc = (((wchar_t)state->__value.__wchb[0]) << 8) + (wchar_t)(t[i]);
	  return (i + 1);
	case MAKE_A:
	  ptr = (unsigned char *)(t + i + 1);
	  break;
	case ERROR:
	default:
	  r->_errno = EILSEQ;
	  return -1;
	}

    }

  state->__state = curr_state;
  return -2;  /* n < bytes needed */
}
#endif /* !__CYGWIN__*/
#endif /* _MB_CAPABLE */