/* Character set conversion with error handling.

   Copyright (C) 2001-2023 Free Software Foundation, Inc.

   Written by Bruno Haible and Simon Josefsson.

   This file 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.

   This file 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */

#include "striconveh.h"

#include <errno.h>

#include <stdlib.h>

#include <string.h>

#if HAVE_ICONV

# include <iconv.h>

# include "unistr.h"

#endif

#include "c-strcase.h"

#include "c-strcaseeq.h"

#ifndef SIZE_MAX

# define SIZE_MAX ((size_t) -1)

#endif

#if HAVE_ICONV

/* The caller must provide an iconveh_t, not just an iconv_t, because when a

   conversion error occurs, we may have to determine the Unicode representation

   of the inconvertible character.  */

int

iconveh_open (const char *to_codeset, const char *from_codeset, iconveh_t *cdp)

{

  iconv_t cd;

  iconv_t cd1;

  iconv_t cd2;

  /* Avoid glibc-2.1 bug with EUC-KR.  */

# if ((__GLIBC__ == 2 && __GLIBC_MINOR__ <= 1) && !defined __UCLIBC__) \

     && !defined _LIBICONV_VERSION

  if (c_strcasecmp (from_codeset, "EUC-KR") == 0

      || c_strcasecmp (to_codeset, "EUC-KR") == 0)

    {

      errno = EINVAL;

      return -1;

    }

# endif

  cd = iconv_open (to_codeset, from_codeset);

  if (STRCASEEQ (from_codeset, "UTF-8", 'U','T','F','-','8',0,0,0,0))

    cd1 = (iconv_t)(-1);

  else

    {

      cd1 = iconv_open ("UTF-8", from_codeset);

      if (cd1 == (iconv_t)(-1))

        {

          int saved_errno = errno;

          if (cd != (iconv_t)(-1))

            iconv_close (cd);

          errno = saved_errno;

          return -1;

        }

    }

  if (STRCASEEQ (to_codeset, "UTF-8", 'U','T','F','-','8',0,0,0,0)

# if (((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 2) || __GLIBC__ > 2) \

      && !defined __UCLIBC__) \

     || _LIBICONV_VERSION >= 0x0105

      || c_strcasecmp (to_codeset, "UTF-8//TRANSLIT") == 0

# endif

     )

    cd2 = (iconv_t)(-1);

  else

    {

      cd2 = iconv_open (to_codeset, "UTF-8");

      if (cd2 == (iconv_t)(-1))

        {

          int saved_errno = errno;

          if (cd1 != (iconv_t)(-1))

            iconv_close (cd1);

          if (cd != (iconv_t)(-1))

            iconv_close (cd);

          errno = saved_errno;

          return -1;

        }

    }

  cdp->cd = cd;

  cdp->cd1 = cd1;

  cdp->cd2 = cd2;

  return 0;

}

int

iconveh_close (const iconveh_t *cd)

{

  if (cd->cd2 != (iconv_t)(-1) && iconv_close (cd->cd2) < 0)

    {

      /* Return -1, but preserve the errno from iconv_close.  */

      int saved_errno = errno;

      if (cd->cd1 != (iconv_t)(-1))

        iconv_close (cd->cd1);

      if (cd->cd != (iconv_t)(-1))

        iconv_close (cd->cd);

      errno = saved_errno;

      return -1;

    }

  if (cd->cd1 != (iconv_t)(-1) && iconv_close (cd->cd1) < 0)

    {

      /* Return -1, but preserve the errno from iconv_close.  */

      int saved_errno = errno;

      if (cd->cd != (iconv_t)(-1))

        iconv_close (cd->cd);

      errno = saved_errno;

      return -1;

    }

  if (cd->cd != (iconv_t)(-1) && iconv_close (cd->cd) < 0)

    return -1;

  return 0;

}

/* iconv_carefully is like iconv, except that it stops as soon as it encounters

   a conversion error, and it returns in *INCREMENTED a boolean telling whether

   it has incremented the input pointers past the error location.  */

# if !defined _LIBICONV_VERSION && !(defined __GLIBC__ && !defined __UCLIBC__)

/* Irix iconv() inserts a NUL byte if it cannot convert.

   NetBSD iconv() inserts a question mark if it cannot convert.

   Only GNU libiconv and GNU libc are known to prefer to fail rather

   than doing a lossy conversion.  */

static size_t

iconv_carefully (iconv_t cd,

                 const char **inbuf, size_t *inbytesleft,

                 char **outbuf, size_t *outbytesleft,

                 bool *incremented)

{

  const char *inptr = *inbuf;

  const char *inptr_end = inptr + *inbytesleft;

  char *outptr = *outbuf;

  size_t outsize = *outbytesleft;

  const char *inptr_before;

  size_t res;

  do

    {

      size_t insize;

      inptr_before = inptr;

      res = (size_t)(-1);

      for (insize = 1; inptr + insize <= inptr_end; insize++)

        {

          res = iconv (cd,

                       (ICONV_CONST char **) &inptr, &insize,

                       &outptr, &outsize);

          if (!(res == (size_t)(-1) && errno == EINVAL))

            break;

          /* iconv can eat up a shift sequence but give EINVAL while attempting

             to convert the first character.  E.g. libiconv does this.  */

          if (inptr > inptr_before)

            {

              res = 0;

              break;

            }

        }

      if (res == 0)

        {

          *outbuf = outptr;

          *outbytesleft = outsize;

        }

    }

  while (res == 0 && inptr < inptr_end);

  *inbuf = inptr;

  *inbytesleft = inptr_end - inptr;

  if (res != (size_t)(-1) && res > 0)

    {

      /* iconv() has already incremented INPTR.  We cannot go back to a

         previous INPTR, otherwise the state inside CD would become invalid,

         if FROM_CODESET is a stateful encoding.  So, tell the caller that

         *INBUF has already been incremented.  */

      *incremented = (inptr > inptr_before);

      errno = EILSEQ;

      return (size_t)(-1);

    }

  else

    {

      *incremented = false;

      return res;

    }

}

# else

#  define iconv_carefully(cd, inbuf, inbytesleft, outbuf, outbytesleft, incremented) \

     (*(incremented) = false, \

      iconv (cd, (ICONV_CONST char **) (inbuf), inbytesleft, outbuf, outbytesleft))

# endif

/* iconv_carefully_1 is like iconv_carefully, except that it stops after

   converting one character or one shift sequence.  */

static size_t

iconv_carefully_1 (iconv_t cd,

                   const char **inbuf, size_t *inbytesleft,

                   char **outbuf, size_t *outbytesleft,

                   bool *incremented)

{

  const char *inptr_before = *inbuf;

  const char *inptr = inptr_before;

  const char *inptr_end = inptr_before + *inbytesleft;

  char *outptr = *outbuf;

  size_t outsize = *outbytesleft;

  size_t res = (size_t)(-1);

  size_t insize;

  for (insize = 1; inptr_before + insize <= inptr_end; insize++)

    {

      inptr = inptr_before;

      res = iconv (cd,

                   (ICONV_CONST char **) &inptr, &insize,

                   &outptr, &outsize);

      if (!(res == (size_t)(-1) && errno == EINVAL))

        break;

      /* iconv can eat up a shift sequence but give EINVAL while attempting

         to convert the first character.  E.g. libiconv does this.  */

      if (inptr > inptr_before)

        {

          res = 0;

          break;

        }

    }

  *inbuf = inptr;

  *inbytesleft = inptr_end - inptr;

# if !defined _LIBICONV_VERSION && !(defined __GLIBC__ && !defined __UCLIBC__)

  /* Irix iconv() inserts a NUL byte if it cannot convert.

     NetBSD iconv() inserts a question mark if it cannot convert.

     Only GNU libiconv and GNU libc are known to prefer to fail rather

     than doing a lossy conversion.  */

  if (res != (size_t)(-1) && res > 0)

    {

      /* iconv() has already incremented INPTR.  We cannot go back to a

         previous INPTR, otherwise the state inside CD would become invalid,

         if FROM_CODESET is a stateful encoding.  So, tell the caller that

         *INBUF has already been incremented.  */

      *incremented = (inptr > inptr_before);

      errno = EILSEQ;

      return (size_t)(-1);

    }

# endif

  if (res != (size_t)(-1))

    {

      *outbuf = outptr;

      *outbytesleft = outsize;

    }

  *incremented = false;

  return res;

}

/* utf8conv_carefully is like iconv, except that

     - it converts from UTF-8 to UTF-8,

     - it stops as soon as it encounters a conversion error, and it returns

       in *INCREMENTED a boolean telling whether it has incremented the input

       pointers past the error location,

     - if one_character_only is true, it stops after converting one

       character.  */

static size_t

utf8conv_carefully (bool one_character_only,

                    const char **inbuf, size_t *inbytesleft,

                    char **outbuf, size_t *outbytesleft,

                    bool *incremented)

{

  const char *inptr = *inbuf;

  size_t insize = *inbytesleft;

  char *outptr = *outbuf;

  size_t outsize = *outbytesleft;

  size_t res;

  res = 0;

  do

    {

      ucs4_t uc;

      int n;

      int m;

      n = u8_mbtoucr (&uc, (const uint8_t *) inptr, insize);

      if (n < 0)

        {

          errno = (n == -2 ? EINVAL : EILSEQ);

          n = u8_mbtouc (&uc, (const uint8_t *) inptr, insize);

          inptr += n;

          insize -= n;

          res = (size_t)(-1);

          *incremented = true;

          break;

        }

      if (outsize == 0)

        {

          errno = E2BIG;

          res = (size_t)(-1);

          *incremented = false;

          break;

        }

      m = u8_uctomb ((uint8_t *) outptr, uc, outsize);

      if (m == -2)

        {

          errno = E2BIG;

          res = (size_t)(-1);

          *incremented = false;

          break;

        }

      inptr += n;

      insize -= n;

      if (m == -1)

        {

          errno = EILSEQ;

          res = (size_t)(-1);

          *incremented = true;

          break;

        }

      outptr += m;

      outsize -= m;

    }

  while (!one_character_only && insize > 0);

  *inbuf = inptr;

  *inbytesleft = insize;

  *outbuf = outptr;

  *outbytesleft = outsize;

  return res;

}

static int

mem_cd_iconveh_internal (const char *src, size_t srclen,

                         iconv_t cd, iconv_t cd1, iconv_t cd2,

                         enum iconv_ilseq_handler handler,

                         size_t extra_alloc,

                         size_t *offsets,

                         char **resultp, size_t *lengthp)

{

  /* When a conversion error occurs, we cannot start using CD1 and CD2 at

     this point: FROM_CODESET may be a stateful encoding like ISO-2022-KR.

     Instead, we have to start afresh from the beginning of SRC.  */

  /* Use a temporary buffer, so that for small strings, a single malloc()

     call will be sufficient.  */

# define tmpbufsize 4096

  /* The alignment is needed when converting e.g. to glibc's WCHAR_T or

     libiconv's UCS-4-INTERNAL encoding.  */

  union { unsigned int align; char buf[tmpbufsize]; } tmp;

# define tmpbuf tmp.buf

  char *initial_result;

  char *result;

  size_t allocated;

  size_t length;

  size_t last_length = (size_t)(-1); /* only needed if offsets != NULL */

  if (*resultp != NULL && *lengthp >= sizeof (tmpbuf))

    {

      initial_result = *resultp;

      allocated = *lengthp;

    }

  else

    {

      initial_result = tmpbuf;

      allocated = sizeof (tmpbuf);

    }

  result = initial_result;

  /* Test whether a direct conversion is possible at all.  */

  if (cd == (iconv_t)(-1))

    goto indirectly;

  if (offsets != NULL)

    {

      size_t i;

      for (i = 0; i < srclen; i++)

        offsets[i] = (size_t)(-1);

      last_length = (size_t)(-1);

    }

  length = 0;

  /* First, try a direct conversion, and see whether a conversion error

     occurs at all.  */

  {

    const char *inptr = src;

    size_t insize = srclen;

    /* Avoid glibc-2.1 bug and Solaris 2.7-2.9 bug.  */

# if defined _LIBICONV_VERSION \

     || !(((__GLIBC__ == 2 && __GLIBC_MINOR__ <= 1) && !defined __UCLIBC__) \

          || defined __sun)

    /* Set to the initial state.  */

    iconv (cd, NULL, NULL, NULL, NULL);

# endif

    while (insize > 0)

      {

        char *outptr = result + length;

        size_t outsize = allocated - extra_alloc - length;

        bool incremented;

        size_t res;

        bool grow;

        if (offsets != NULL)

          {

            if (length != last_length) /* ensure that offset[] be increasing */

              {

                offsets[inptr - src] = length;

                last_length = length;

              }

            res = iconv_carefully_1 (cd,

                                     &inptr, &insize,

                                     &outptr, &outsize,

                                     &incremented);

          }

        else

          /* Use iconv_carefully instead of iconv here, because:

             - If TO_CODESET is UTF-8, we can do the error handling in this

               loop, no need for a second loop,

             - With iconv() implementations other than GNU libiconv and GNU

               libc, if we use iconv() in a big swoop, checking for an E2BIG

               return, we lose the number of irreversible conversions.  */

          res = iconv_carefully (cd,

                                 &inptr, &insize,

                                 &outptr, &outsize,

                                 &incremented);

        length = outptr - result;

        grow = (length + extra_alloc > allocated / 2);

        if (res == (size_t)(-1))

          {

            if (errno == E2BIG)

              grow = true;

            else if (errno == EINVAL)

              break;

            else if (errno == EILSEQ && handler != iconveh_error)

              {

                if (cd2 == (iconv_t)(-1))

                  {

                    /* TO_CODESET is UTF-8.  */

                    /* Error handling can produce up to 1 or 3 bytes of

                       output.  */

                    size_t extra_need =

                      (handler == iconveh_replacement_character ? 3 : 1);

                    if (length + extra_need + extra_alloc > allocated)

                      {

                        char *memory;

                        allocated = 2 * allocated;

                        if (length + extra_need + extra_alloc > allocated)

                          allocated = 2 * allocated;

                        if (length + extra_need + extra_alloc > allocated)

                          abort ();

                        if (result == initial_result)

                          memory = (char *) malloc (allocated);

                        else

                          memory = (char *) realloc (result, allocated);

                        if (memory == NULL)

                          {

                            if (result != initial_result)

                              free (result);

                            errno = ENOMEM;

                            return -1;

                          }

                        if (result == initial_result)

                          memcpy (memory, initial_result, length);

                        result = memory;

                        grow = false;

                      }

                    /* The input is invalid in FROM_CODESET.  Eat up one byte

                       and emit a replacement character or a question mark.  */

                    if (!incremented)

                      {

                        if (insize == 0)

                          abort ();

                        inptr++;

                        insize--;

                      }

                    if (handler == iconveh_replacement_character)

                      {

                        /* U+FFFD in UTF-8 encoding.  */

                        result[length+0] = '\357';

                        result[length+1] = '\277';

                        result[length+2] = '\275';

                        length += 3;

                      }

                    else

                      {

                        result[length] = '?';

                        length++;

                      }

                  }

                else

                  goto indirectly;

              }

            else

              {

                if (result != initial_result)

                  free (result);

                return -1;

              }

          }

        if (insize == 0)

          break;

        if (grow)

          {

            char *memory;

            allocated = 2 * allocated;

            if (result == initial_result)

              memory = (char *) malloc (allocated);

            else

              memory = (char *) realloc (result, allocated);

            if (memory == NULL)

              {

                if (result != initial_result)

                  free (result);

                errno = ENOMEM;

                return -1;

              }

            if (result == initial_result)

              memcpy (memory, initial_result, length);

            result = memory;

          }

      }

  }

  /* Now get the conversion state back to the initial state.

     But avoid glibc-2.1 bug and Solaris 2.7 bug.  */

#if defined _LIBICONV_VERSION \

    || !(((__GLIBC__ == 2 && __GLIBC_MINOR__ <= 1) && !defined __UCLIBC__) \

         || defined __sun)

  for (;;)

    {

      char *outptr = result + length;

      size_t outsize = allocated - extra_alloc - length;

      size_t res;

      res = iconv (cd, NULL, NULL, &outptr, &outsize);

      length = outptr - result;

      if (res == (size_t)(-1))

        {

          if (errno == E2BIG)

            {

              char *memory;

              allocated = 2 * allocated;

              if (result == initial_result)

                memory = (char *) malloc (allocated);

              else

                memory = (char *) realloc (result, allocated);

              if (memory == NULL)

                {

                  if (result != initial_result)

                    free (result);

                  errno = ENOMEM;

                  return -1;

                }

              if (result == initial_result)

                memcpy (memory, initial_result, length);

              result = memory;

            }

          else

            {

              if (result != initial_result)

                free (result);

              return -1;

            }

        }

      else

        break;

    }

#endif

  /* The direct conversion succeeded.  */

  goto done;

 indirectly:

  /* The direct conversion failed.

     Use a conversion through UTF-8.  */

  if (offsets != NULL)

    {

      size_t i;

      for (i = 0; i < srclen; i++)

        offsets[i] = (size_t)(-1);

      last_length = (size_t)(-1);

    }

  length = 0;

  {

    const bool slowly = (offsets != NULL || handler == iconveh_error);

# define utf8bufsize 4096 /* may also be smaller or larger than tmpbufsize */

    char utf8buf[utf8bufsize + 3];

    size_t utf8len = 0;

    const char *in1ptr = src;

    size_t in1size = srclen;

    bool do_final_flush1 = true;

    bool do_final_flush2 = true;

    /* Avoid glibc-2.1 bug and Solaris 2.7-2.9 bug.  */

# if defined _LIBICONV_VERSION \

     || !(((__GLIBC__ == 2 && __GLIBC_MINOR__ <= 1) && !defined __UCLIBC__) \

          || defined __sun)

    /* Set to the initial state.  */

    if (cd1 != (iconv_t)(-1))

      iconv (cd1, NULL, NULL, NULL, NULL);

    if (cd2 != (iconv_t)(-1))

      iconv (cd2, NULL, NULL, NULL, NULL);

# endif

    while (in1size > 0 || do_final_flush1 || utf8len > 0 || do_final_flush2)

      {

        char *out1ptr = utf8buf + utf8len;

        size_t out1size = utf8bufsize - utf8len;

        bool incremented1;

        size_t res1;

        int errno1;

        /* Conversion step 1: from FROM_CODESET to UTF-8.  */

        if (in1size > 0)

          {

            if (offsets != NULL

                && length != last_length) /* ensure that offset[] be increasing */

              {

                offsets[in1ptr - src] = length;

                last_length = length;

              }

            if (cd1 != (iconv_t)(-1))

              {

                if (slowly)

                  res1 = iconv_carefully_1 (cd1,

                                            &in1ptr, &in1size,

                                            &out1ptr, &out1size,

                                            &incremented1);

                else

                  res1 = iconv_carefully (cd1,

                                          &in1ptr, &in1size,

                                          &out1ptr, &out1size,

                                          &incremented1);

              }

            else

              {

                /* FROM_CODESET is UTF-8.  */

                res1 = utf8conv_carefully (slowly,

                                           &in1ptr, &in1size,

                                           &out1ptr, &out1size,

                                           &incremented1);

              }

          }

        else if (do_final_flush1)

          {

            /* Now get the conversion state of CD1 back to the initial state.

               But avoid glibc-2.1 bug and Solaris 2.7 bug.  */

# if defined _LIBICONV_VERSION \

     || !(((__GLIBC__ == 2 && __GLIBC_MINOR__ <= 1) && !defined __UCLIBC__) \

          || defined __sun)

            if (cd1 != (iconv_t)(-1))

              res1 = iconv (cd1, NULL, NULL, &out1ptr, &out1size);

            else

# endif

              res1 = 0;

            do_final_flush1 = false;

            incremented1 = true;

          }

        else

          {

            res1 = 0;

            incremented1 = true;

          }

        if (res1 == (size_t)(-1)

            && !(errno == E2BIG || errno == EINVAL || errno == EILSEQ))

          {

            if (result != initial_result)

              free (result);

            return -1;

          }

        if (res1 == (size_t)(-1)

            && errno == EILSEQ && handler != iconveh_error)

          {

            /* The input is invalid in FROM_CODESET.  Eat up one byte and

               emit a U+FFFD character or a question mark.  Room for this

               character was allocated at the end of utf8buf.  */

            if (!incremented1)

              {

                if (in1size == 0)

                  abort ();

                in1ptr++;

                in1size--;

              }

            if (handler == iconveh_replacement_character)

              {

                /* U+FFFD in UTF-8 encoding.  */

                out1ptr[0] = '\357';

                out1ptr[1] = '\277';

                out1ptr[2] = '\275';

                out1ptr += 3;

              }

            else

              *out1ptr++ = '?';

            res1 = 0;

          }

        errno1 = errno;

        utf8len = out1ptr - utf8buf;

        if (offsets != NULL

            || in1size == 0

            || utf8len > utf8bufsize / 2

            || (res1 == (size_t)(-1) && errno1 == E2BIG))

          {

            /* Conversion step 2: from UTF-8 to TO_CODESET.  */

            const char *in2ptr = utf8buf;

            size_t in2size = utf8len;

            while (in2size > 0

                   || (in1size == 0 && !do_final_flush1 && do_final_flush2))

              {

                char *out2ptr = result + length;

                size_t out2size = allocated - extra_alloc - length;

                bool incremented2;

                size_t res2;

                bool grow;

                if (in2size > 0)

                  {

                    if (cd2 != (iconv_t)(-1))

                      res2 = iconv_carefully (cd2,

                                              &in2ptr, &in2size,

                                              &out2ptr, &out2size,

                                              &incremented2);

                    else

                      /* TO_CODESET is UTF-8.  */

                      res2 = utf8conv_carefully (false,

                                                 &in2ptr, &in2size,

                                                 &out2ptr, &out2size,

                                                 &incremented2);

                  }

                else /* in1size == 0 && !do_final_flush1

                        && in2size == 0 && do_final_flush2 */

                  {

                    /* Now get the conversion state of CD1 back to the initial

                       state.  But avoid glibc-2.1 bug and Solaris 2.7 bug.  */

# if defined _LIBICONV_VERSION \

     || !(((__GLIBC__ == 2 && __GLIBC_MINOR__ <= 1) && !defined __UCLIBC__) \

          || defined __sun)

                    if (cd2 != (iconv_t)(-1))

                      res2 = iconv (cd2, NULL, NULL, &out2ptr, &out2size);

                    else

# endif

                      res2 = 0;

                    do_final_flush2 = false;

                    incremented2 = true;

                  }

                length = out2ptr - result;

                grow = (length + extra_alloc > allocated / 2);

                if (res2 == (size_t)(-1))

                  {

                    if (errno == E2BIG)

                      grow = true;

                    else if (errno == EINVAL)

                      break;

                    else if (errno == EILSEQ && handler != iconveh_error)

                      {

                        /* Error handling can produce up to 10 bytes of UTF-8

                           output.  But TO_CODESET may be UCS-2, UTF-16 or

                           UCS-4, so use CD2 here as well.  */

                        char scratchbuf[10];

                        size_t scratchlen;

                        ucs4_t uc;

                        const char *inptr;

                        size_t insize;

                        size_t res;

                        if (incremented2)

                          {

                            if (u8_prev (&uc, (const uint8_t *) in2ptr,

                                         (const uint8_t *) utf8buf)

                                == NULL)

                              abort ();

                          }

                        else

                          {

                            int n;

                            if (in2size == 0)

                              abort ();

                            n = u8_mbtouc_unsafe (&uc, (const uint8_t *) in2ptr,

                                                  in2size);

                            in2ptr += n;

                            in2size -= n;

                          }

                        if (handler == iconveh_escape_sequence)

                          {

                            static char hex[16] = "0123456789ABCDEF";

                            scratchlen = 0;

                            scratchbuf[scratchlen++] = '\\';

                            if (uc < 0x10000)

                              scratchbuf[scratchlen++] = 'u';

                            else

                              {

                                scratchbuf[scratchlen++] = 'U';

                                scratchbuf[scratchlen++] = hex[(uc>>28) & 15];

                                scratchbuf[scratchlen++] = hex[(uc>>24) & 15];

                                scratchbuf[scratchlen++] = hex[(uc>>20) & 15];

                                scratchbuf[scratchlen++] = hex[(uc>>16) & 15];

                              }

                            scratchbuf[scratchlen++] = hex[(uc>>12) & 15];

                            scratchbuf[scratchlen++] = hex[(uc>>8) & 15];

                            scratchbuf[scratchlen++] = hex[(uc>>4) & 15];

                            scratchbuf[scratchlen++] = hex[uc & 15];

                          }

                        else if (handler == iconveh_replacement_character)

                          {

                            /* U+FFFD in UTF-8 encoding.  */

                            scratchbuf[0] = '\357';

                            scratchbuf[1] = '\277';

                            scratchbuf[2] = '\275';

                            scratchlen = 3;

                          }

                        else

                          {

                            scratchbuf[0] = '?';

                            scratchlen = 1;

                          }

                        inptr = scratchbuf;

                        insize = scratchlen;

                        if (cd2 != (iconv_t)(-1))

                          {

                            char *out2ptr_try = out2ptr;

                            size_t out2size_try = out2size;

                            res = iconv (cd2,

                                         (ICONV_CONST char **) &inptr, &insize,

                                         &out2ptr_try, &out2size_try);

                            if (handler == iconveh_replacement_character

                                && (res == (size_t)(-1)

                                    ? errno == EILSEQ

                                    /* FreeBSD iconv(), NetBSD iconv(), and

                                       Solaris 11 iconv() insert a '?' if they

                                       cannot convert.  This is what we want.

                                       But IRIX iconv() inserts a NUL byte if it

                                       cannot convert.

                                       And musl libc iconv() inserts a '*' if it

                                       cannot convert.  */

                                    : (res > 0

                                       && !(out2ptr_try - out2ptr == 1

                                            && *out2ptr == '?'))))

                              {

                                /* The iconv() call failed.

                                   U+FFFD can't be converted to TO_CODESET.

                                   Use '?' instead.  */

                                scratchbuf[0] = '?';

                                scratchlen = 1;

                                inptr = scratchbuf;

                                insize = scratchlen;

                                res = iconv (cd2,

                                             (ICONV_CONST char **) &inptr, &insize,

                                             &out2ptr, &out2size);

                              }

                            else

                              {

                                /* Accept the results of the iconv() call.  */

                                out2ptr = out2ptr_try;

                                out2size = out2size_try;

                                res = 0;

                              }

                          }

                        else

                          {

                            /* TO_CODESET is UTF-8.  */

                            if (out2size >= insize)