#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 *)
#ifdef __CYGWIN__
   /* Cygwin starts up in UTF-8 mode. */
   = __utf8_mbtowc;
#else
   = __ascii_mbtowc;
#endif

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;

#ifdef __CYGWIN__
  if ((wchar_t)*t >= 0x80)
    {
      r->_errno = EILSEQ;
      return -1;
    }
#endif

  *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 == 0)
    ch = t[i++];
  else
    ch = state->__value.__wchb[0];

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

  if (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;
      if (state->__count == 0)
	state->__count = 1;
      else if (n < (size_t)-1)
	++n;
      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;
      if (state->__count == 1)
	state->__count = 2;
      else if (n < (size_t)-1)
	++n;
      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);
      *pwc = tmp;
      return i;
    }
  if (ch >= 0xf0 && ch <= 0xf4)
    {
      /* 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)
	  || (state->__value.__wchb[0] == 0xf4 && ch >= 0x90))
	{
	  /* overlong UTF-8 sequence or result is > 0x10ffff */
	  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;
      if (state->__count == 2)
	state->__count = 3;
      else if (n < (size_t)-1)
	++n;
      if (state->__count == 3 && 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.  The first
	     three bytes of a UTF-8 sequence are enough to generate the
	     first half of a UTF-16 surrogate pair.  As return value we
	     choose to return the number of bytes actually read up to
	     here.
	     The second half of the surrogate pair is returned in case we
	     recognize the special __count value of four, and the next
	     byte is actually a valid value.  See below. */
	  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);
	  state->__count = 4;
	  *pwc = 0xd800 | ((tmp - 0x10000) >> 10);
	  return i;
	}
      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 (state->__count == 4 && sizeof(wchar_t) == 2)
	/* Create the second half of the surrogate pair for systems with
	   wchar_t == UTF-16 . */
	*pwc = 0xdc00 | (tmp & 0x3ff);
      else
	*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 (_iseucjp1 (ch))
	{
	  state->__value.__wchb[0] = ch;
	  state->__count = 1;
	  if (n <= 1)
	    return -2;
	  ch = t[i++];
	}
    }
  if (state->__count == 1)
    {
      if (_iseucjp2 (ch))
	{
	  if (state->__value.__wchb[0] == 0x8f)
	    {
	      state->__value.__wchb[1] = ch;
	      state->__count = 2;
	      if (n <= i)
		return -2;
	      ch = t[i++];
	    }
	  else
	    {
	      *pwc = (((wchar_t)state->__value.__wchb[0]) << 8) + (wchar_t)ch;
	      state->__count = 0;
	      return i;
	    }
	}
      else
	{
	  r->_errno = EILSEQ;
	  return -1;
	}
    }
  if (state->__count == 2)
    {
      if (_iseucjp2 (ch))
	{
	  *pwc = (((wchar_t)state->__value.__wchb[1]) << 8)
		 + (wchar_t)(ch & 0x7f);
	  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 */
