/* Character set conversion.

   Copyright (C) 1999-2001, 2007, 2009-2018 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License along

   with this program; if not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */

#include <iconv.h>

#include <stddef.h>

#if REPLACE_ICONV_UTF

# include <errno.h>

# include <stdint.h>

# include <stdlib.h>

# include "unistr.h"

# ifndef uintptr_t

#  define uintptr_t unsigned long

# endif

#endif

#if REPLACE_ICONV_UTF

/* UTF-{16,32}{BE,LE} converters taken from GNU libiconv 1.11.  */

/* Return code if invalid. (xxx_mbtowc) */

# define RET_ILSEQ      -1

/* Return code if no bytes were read. (xxx_mbtowc) */

# define RET_TOOFEW     -2

/* Return code if invalid. (xxx_wctomb) */

# define RET_ILUNI      -1

/* Return code if output buffer is too small. (xxx_wctomb, xxx_reset) */

# define RET_TOOSMALL   -2

/*

 * UTF-16BE

 */

/* Specification: RFC 2781 */

static int

utf16be_mbtowc (ucs4_t *pwc, const unsigned char *s, size_t n)

{

  if (n >= 2)

    {

      ucs4_t wc = (s[0] << 8) + s[1];

      if (wc >= 0xd800 && wc < 0xdc00)

        {

          if (n >= 4)

            {

              ucs4_t wc2 = (s[2] << 8) + s[3];

              if (!(wc2 >= 0xdc00 && wc2 < 0xe000))

                return RET_ILSEQ;

              *pwc = 0x10000 + ((wc - 0xd800) << 10) + (wc2 - 0xdc00);

              return 4;

            }

        }

      else if (wc >= 0xdc00 && wc < 0xe000)

        {

          return RET_ILSEQ;

        }

      else

        {

          *pwc = wc;

          return 2;

        }

    }

  return RET_TOOFEW;

}

static int

utf16be_wctomb (unsigned char *r, ucs4_t wc, size_t n)

{

  if (!(wc >= 0xd800 && wc < 0xe000))

    {

      if (wc < 0x10000)

        {

          if (n >= 2)

            {

              r[0] = (unsigned char) (wc >> 8);

              r[1] = (unsigned char) wc;

              return 2;

            }

          else

            return RET_TOOSMALL;

        }

      else if (wc < 0x110000)

        {

          if (n >= 4)

            {

              ucs4_t wc1 = 0xd800 + ((wc - 0x10000) >> 10);

              ucs4_t wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);

              r[0] = (unsigned char) (wc1 >> 8);

              r[1] = (unsigned char) wc1;

              r[2] = (unsigned char) (wc2 >> 8);

              r[3] = (unsigned char) wc2;

              return 4;

            }

          else

            return RET_TOOSMALL;

        }

    }

  return RET_ILUNI;

}

/*

 * UTF-16LE

 */

/* Specification: RFC 2781 */

static int

utf16le_mbtowc (ucs4_t *pwc, const unsigned char *s, size_t n)

{

  if (n >= 2)

    {

      ucs4_t wc = s[0] + (s[1] << 8);

      if (wc >= 0xd800 && wc < 0xdc00)

        {

          if (n >= 4)

            {

              ucs4_t wc2 = s[2] + (s[3] << 8);

              if (!(wc2 >= 0xdc00 && wc2 < 0xe000))

                return RET_ILSEQ;

              *pwc = 0x10000 + ((wc - 0xd800) << 10) + (wc2 - 0xdc00);

              return 4;

            }

        }

      else if (wc >= 0xdc00 && wc < 0xe000)

        {

          return RET_ILSEQ;

        }

      else

        {

          *pwc = wc;

          return 2;

        }

    }

  return RET_TOOFEW;

}

static int

utf16le_wctomb (unsigned char *r, ucs4_t wc, size_t n)

{

  if (!(wc >= 0xd800 && wc < 0xe000))

    {

      if (wc < 0x10000)

        {

          if (n >= 2)

            {

              r[0] = (unsigned char) wc;

              r[1] = (unsigned char) (wc >> 8);

              return 2;

            }

          else

            return RET_TOOSMALL;

        }

      else if (wc < 0x110000)

        {

          if (n >= 4)

            {

              ucs4_t wc1 = 0xd800 + ((wc - 0x10000) >> 10);

              ucs4_t wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);

              r[0] = (unsigned char) wc1;

              r[1] = (unsigned char) (wc1 >> 8);

              r[2] = (unsigned char) wc2;

              r[3] = (unsigned char) (wc2 >> 8);

              return 4;

            }

          else

            return RET_TOOSMALL;

        }

    }

  return RET_ILUNI;

}

/*

 * UTF-32BE

 */

/* Specification: Unicode 3.1 Standard Annex #19 */

static int

utf32be_mbtowc (ucs4_t *pwc, const unsigned char *s, size_t n)

{

  if (n >= 4)

    {

      ucs4_t wc = (s[0] << 24) + (s[1] << 16) + (s[2] << 8) + s[3];

      if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000))

        {

          *pwc = wc;

          return 4;

        }

      else

        return RET_ILSEQ;

    }

  return RET_TOOFEW;

}

static int

utf32be_wctomb (unsigned char *r, ucs4_t wc, size_t n)

{

  if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000))

    {

      if (n >= 4)

        {

          r[0] = 0;

          r[1] = (unsigned char) (wc >> 16);

          r[2] = (unsigned char) (wc >> 8);

          r[3] = (unsigned char) wc;

          return 4;

        }

      else

        return RET_TOOSMALL;

    }

  return RET_ILUNI;

}

/*

 * UTF-32LE

 */

/* Specification: Unicode 3.1 Standard Annex #19 */

static int

utf32le_mbtowc (ucs4_t *pwc, const unsigned char *s, size_t n)

{

  if (n >= 4)

    {

      ucs4_t wc = s[0] + (s[1] << 8) + (s[2] << 16) + (s[3] << 24);

      if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000))

        {

          *pwc = wc;

          return 4;

        }

      else

        return RET_ILSEQ;

    }

  return RET_TOOFEW;

}

static int

utf32le_wctomb (unsigned char *r, ucs4_t wc, size_t n)

{

  if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000))

    {

      if (n >= 4)

        {

          r[0] = (unsigned char) wc;

          r[1] = (unsigned char) (wc >> 8);

          r[2] = (unsigned char) (wc >> 16);

          r[3] = 0;

          return 4;

        }

      else

        return RET_TOOSMALL;

    }

  return RET_ILUNI;

}

#endif

size_t

rpl_iconv (iconv_t cd,

           ICONV_CONST char **inbuf, size_t *inbytesleft,

           char **outbuf, size_t *outbytesleft)

#undef iconv

{

#if REPLACE_ICONV_UTF

  switch ((uintptr_t) cd)

    {

      {

        int (*xxx_wctomb) (unsigned char *, ucs4_t, size_t);

        case (uintptr_t) _ICONV_UTF8_UTF16BE:

          xxx_wctomb = utf16be_wctomb;

          goto loop_from_utf8;

        case (uintptr_t) _ICONV_UTF8_UTF16LE:

          xxx_wctomb = utf16le_wctomb;

          goto loop_from_utf8;

        case (uintptr_t) _ICONV_UTF8_UTF32BE:

          xxx_wctomb = utf32be_wctomb;

          goto loop_from_utf8;

        case (uintptr_t) _ICONV_UTF8_UTF32LE:

          xxx_wctomb = utf32le_wctomb;

          goto loop_from_utf8;

       loop_from_utf8:

        if (inbuf == NULL || *inbuf == NULL)

          return 0;

        {

          ICONV_CONST char *inptr = *inbuf;

          size_t inleft = *inbytesleft;

          char *outptr = *outbuf;

          size_t outleft = *outbytesleft;

          size_t res = 0;

          while (inleft > 0)

            {

              ucs4_t uc;

              int m = u8_mbtoucr (&uc, (const uint8_t *) inptr, inleft);

              if (m <= 0)

                {

                  if (m == -1)

                    {

                      errno = EILSEQ;

                      res = (size_t)(-1);

                      break;

                    }

                  if (m == -2)

                    {

                      errno = EINVAL;

                      res = (size_t)(-1);

                      break;

                    }

                  abort ();

                }

              else

                {

                  int n = xxx_wctomb ((uint8_t *) outptr, uc, outleft);

                  if (n < 0)

                    {

                      if (n == RET_ILUNI)

                        {

                          errno = EILSEQ;

                          res = (size_t)(-1);

                          break;

                        }

                      if (n == RET_TOOSMALL)

                        {

                          errno = E2BIG;

                          res = (size_t)(-1);

                          break;

                        }

                      abort ();

                    }

                  else

                    {

                      inptr += m;

                      inleft -= m;

                      outptr += n;

                      outleft -= n;

                    }

                }

            }

          *inbuf = inptr;

          *inbytesleft = inleft;

          *outbuf = outptr;

          *outbytesleft = outleft;

          return res;

        }

      }

      {

        int (*xxx_mbtowc) (ucs4_t *, const unsigned char *, size_t);

        case (uintptr_t) _ICONV_UTF16BE_UTF8:

          xxx_mbtowc = utf16be_mbtowc;

          goto loop_to_utf8;

        case (uintptr_t) _ICONV_UTF16LE_UTF8:

          xxx_mbtowc = utf16le_mbtowc;

          goto loop_to_utf8;

        case (uintptr_t) _ICONV_UTF32BE_UTF8:

          xxx_mbtowc = utf32be_mbtowc;

          goto loop_to_utf8;

        case (uintptr_t) _ICONV_UTF32LE_UTF8:

          xxx_mbtowc = utf32le_mbtowc;

          goto loop_to_utf8;

       loop_to_utf8:

        if (inbuf == NULL || *inbuf == NULL)

          return 0;

        {

          ICONV_CONST char *inptr = *inbuf;

          size_t inleft = *inbytesleft;

          char *outptr = *outbuf;

          size_t outleft = *outbytesleft;

          size_t res = 0;

          while (inleft > 0)

            {

              ucs4_t uc;

              int m = xxx_mbtowc (&uc, (const uint8_t *) inptr, inleft);

              if (m <= 0)

                {

                  if (m == RET_ILSEQ)

                    {

                      errno = EILSEQ;

                      res = (size_t)(-1);

                      break;

                    }

                  if (m == RET_TOOFEW)

                    {

                      errno = EINVAL;

                      res = (size_t)(-1);

                      break;

                    }

                  abort ();

                }

              else

                {

                  int n = u8_uctomb ((uint8_t *) outptr, uc, outleft);

                  if (n < 0)

                    {

                      if (n == -1)

                        {

                          errno = EILSEQ;

                          res = (size_t)(-1);

                          break;

                        }

                      if (n == -2)

                        {

                          errno = E2BIG;

                          res = (size_t)(-1);

                          break;

                        }

                      abort ();

                    }

                  else

                    {

                      inptr += m;

                      inleft -= m;

                      outptr += n;

                      outleft -= n;

                    }

                }

            }

          *inbuf = inptr;

          *inbytesleft = inleft;

          *outbuf = outptr;

          *outbytesleft = outleft;

          return res;

        }

      }

    }

#endif

  return iconv (cd, inbuf, inbytesleft, outbuf, outbytesleft);

}