/* Copyright (C) 2000-2023 Free Software Foundation, Inc.
   This file is part of the GNU LIBICONV Library.

   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 of the License, 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"
#ifndef ICONV_CONST
# define ICONV_CONST
#endif

#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iconv.h>
#include <errno.h>
#include <locale.h>
#include <fcntl.h>

/* Ensure that iconv_no_i18n does not depend on libintl.  */
#ifdef NO_I18N
# undef ENABLE_NLS
# undef ENABLE_RELOCATABLE
#endif

#include "binary-io.h"
#include "progname.h"
#include "relocatable.h"
#include "safe-read.h"
#include "xalloc.h"
#include "uniwidth.h"
#include "uniwidth/cjk.h"

#ifdef __MVS__
#include "zos-tag.h"
#endif

/* Ensure that iconv_no_i18n does not depend on libintl.  */
#ifdef NO_I18N
#include <stdarg.h>
static void
error (int status, int errnum, const char *message, ...)
{
  va_list args;

  fflush(stdout);
  fprintf(stderr,"%s: ",program_name);
  va_start(args,message);
  vfprintf(stderr,message,args);
  va_end(args);
  if (errnum) {
    const char *s = strerror(errnum);
    if (s == NULL)
      s = "Unknown system error";
  }
  putc('\n',stderr);
  fflush(stderr);
  if (status)
    exit(status);
}
#else
# include "error.h"
#endif

#include "gettext.h"

#define _(str) gettext(str)

/* Ensure that iconv_no_i18n does not depend on libintl.  */
#ifdef NO_I18N
# define xmalloc malloc
# define xalloc_die abort
#endif

/* Locale independent test for a decimal digit.
   Argument can be  'char' or 'unsigned char'.  (Whereas the argument of
   <ctype.h> isdigit must be an 'unsigned char'.)  */
#undef isdigit
#define isdigit(c) ((unsigned int) ((c) - '0') < 10)

/* Locale independent test for a printable character.
   Argument can be  'char' or 'unsigned char'.  (Whereas the argument of
   <ctype.h> isdigit must be an 'unsigned char'.)  */
#define c_isprint(c) ((c) >= ' ' && (c) <= '~')

/* ========================================================================= */

static int discard_unconvertible = 0;
static int silent = 0;

static void usage (int exitcode)
{
  if (exitcode != 0) {
    const char* helpstring1 =
      /* TRANSLATORS: The first line of the short usage message.  */
      _("Usage: iconv [-c] [-s] [-f fromcode] [-t tocode] [file ...]");
    const char* helpstring2 =
      /* TRANSLATORS: The second line of the short usage message.
         Align it correctly against the first line.  */
      _("or:    iconv -l");
    fprintf(stderr, "%s\n%s\n", helpstring1, helpstring2);
    fprintf(stderr, _("Try '%s --help' for more information.\n"), program_name);
  } else {
    /* xgettext: no-wrap */
    /* TRANSLATORS: The first line of the long usage message.
       The %s placeholder expands to the program name.  */
    printf(_("\
Usage: %s [OPTION...] [-f ENCODING] [-t ENCODING] [INPUTFILE...]\n"),
           program_name);
    /* xgettext: no-wrap */
    /* TRANSLATORS: The second line of the long usage message.
       Align it correctly against the first line.
       The %s placeholder expands to the program name.  */
    printf(_("\
or:    %s -l\n"),
           program_name);
    printf("\n");
    /* xgettext: no-wrap */
    /* TRANSLATORS: Description of the iconv program.  */
    printf(_("\
Converts text from one encoding to another encoding.\n"));
    printf("\n");
    /* xgettext: no-wrap */
    printf(_("\
Options controlling the input and output format:\n"));
    /* xgettext: no-wrap */
    printf(_("\
  -f ENCODING, --from-code=ENCODING\n\
                              the encoding of the input\n"));
    /* xgettext: no-wrap */
    printf(_("\
  -t ENCODING, --to-code=ENCODING\n\
                              the encoding of the output\n"));
    printf("\n");
    /* xgettext: no-wrap */
    printf(_("\
Options controlling conversion problems:\n"));
    /* xgettext: no-wrap */
    printf(_("\
  -c                          discard unconvertible characters\n"));
    /* xgettext: no-wrap */
    printf(_("\
  --unicode-subst=FORMATSTRING\n\
                              substitution for unconvertible Unicode characters\n"));
    /* xgettext: no-wrap */
    printf(_("\
  --byte-subst=FORMATSTRING   substitution for unconvertible bytes\n"));
    /* xgettext: no-wrap */
    printf(_("\
  --widechar-subst=FORMATSTRING\n\
                              substitution for unconvertible wide characters\n"));
    printf("\n");
    /* xgettext: no-wrap */
    printf(_("\
Options controlling error output:\n"));
    /* xgettext: no-wrap */
    printf(_("\
  -s, --silent                suppress error messages about conversion problems\n"));
    printf("\n");
    /* xgettext: no-wrap */
    printf(_("\
Informative output:\n"));
    /* xgettext: no-wrap */
    printf(_("\
  -l, --list                  list the supported encodings\n"));
    /* xgettext: no-wrap */
    printf(_("\
  --help                      display this help and exit\n"));
    /* xgettext: no-wrap */
    printf(_("\
  --version                   output version information and exit\n"));
    printf("\n");
    /* TRANSLATORS: The first placeholder is the web address of the Savannah
       project of this package.  The second placeholder is the bug-reporting
       email address for this package.  Please add _another line_ saying
       "Report translation bugs to <...>\n" with the address for translation
       bugs (typically your translation team's web or email address).  */
    printf(_("\
Report bugs in the bug tracker at <%s>\n\
or by email to <%s>.\n"),
           "https://savannah.gnu.org/projects/libiconv",
           "bug-gnu-libiconv@gnu.org");
  }
  exit(exitcode);
}

static void print_version (void)
{
  printf("iconv (GNU libiconv %d.%d)\n",
         _libiconv_version >> 8, _libiconv_version & 0xff);
  printf("Copyright (C) %s Free Software Foundation, Inc.\n", "2000-2022");
  /* xgettext: no-wrap */
  /* TRANSLATORS: The %s placeholder is the web address of the GPL license.  */
  printf (_("\
License GPLv3+: GNU GPL version 3 or later <%s>\n\
This is free software: you are free to change and redistribute it.\n\
There is NO WARRANTY, to the extent permitted by law.\n"),
          "https://gnu.org/licenses/gpl.html");
  /* TRANSLATORS: The %s placeholder expands to an author's name.  */
  printf(_("Written by %s.\n"),"Bruno Haible");
  exit(EXIT_SUCCESS);
}

static int print_one (unsigned int namescount, const char * const * names,
                      void* data)
{
  unsigned int i;
  (void)data;
  for (i = 0; i < namescount; i++) {
    if (i > 0)
      putc(' ',stdout);
    fputs(names[i],stdout);
  }
  putc('\n',stdout);
  return 0;
}

/* ========================================================================= */

/* Line number and column position. */
static unsigned int line;
static unsigned int column;
static const char* cjkcode;
/* Update the line number and column position after a character was
   successfully converted. */
static void update_line_column (unsigned int uc, void* data)
{
  if (uc == 0x000A) {
    line++;
    column = 0;
  } else {
    int width = uc_width(uc, cjkcode);
    if (width >= 0)
      column += width;
    else if (uc == 0x0009)
      column += 8 - (column % 8);
  }
}

/* ========================================================================= */

/* Production of placeholder strings as fallback for unconvertible
   characters. */

/* Check that the argument is a format string taking either no argument
   or exactly one unsigned integer argument. Returns the maximum output
   size of the format string. */
static size_t check_subst_formatstring (const char *format, const char *param_name)
{
  /* C format strings are described in POSIX (IEEE P1003.1 2001), section
     XSH 3 fprintf().  See also Linux fprintf(3) manual page.
     For simplicity, we don't accept
       - the '%m$' reordering syntax,
       - the 'I' flag,
       - width specifications referring to an argument,
       - precision specifications referring to an argument,
       - size specifiers,
       - format specifiers other than 'o', 'u', 'x', 'X'.
     What remains?
     A directive
       - starts with '%',
       - is optionally followed by any of the characters '#', '0', '-', ' ',
         '+', "'", each of which acts as a flag,
       - is optionally followed by a width specification: a nonempty digit
         sequence,
       - is optionally followed by '.' and a precision specification: a
         nonempty digit sequence,
       - is finished by a specifier
         - '%', that needs no argument,
         - 'o', 'u', 'x', 'X', that need an unsigned integer argument.
   */
  size_t maxsize = 0;
  unsigned int unnumbered_arg_count = 0;

  for (; *format != '\0';) {
    if (*format++ == '%') {
      /* A directive. */
      unsigned int width = 0;
      unsigned int precision = 0;
      unsigned int length;
      /* Parse flags. */
      for (;;) {
        if (*format == ' ' || *format == '+' || *format == '-'
            || *format == '#' || *format == '0' || *format == '\'')
          format++;
        else
          break;
      }
      /* Parse width. */
      if (*format == '*')
        error(EXIT_FAILURE,0,
              /* TRANSLATORS: An error message.
                 The %s placeholder expands to a command-line option.  */
              _("%s argument: A format directive with a variable width is not allowed here."),
              param_name);
      if (isdigit (*format)) {
        do {
          width = 10*width + (*format - '0');
          format++;
        } while (isdigit (*format));
      }
      /* Parse precision. */
      if (*format == '.') {
        format++;
        if (*format == '*')
          error(EXIT_FAILURE,0,
                /* TRANSLATORS: An error message.
                   The %s placeholder expands to a command-line option.  */
                _("%s argument: A format directive with a variable precision is not allowed here."),
                param_name);
        if (isdigit (*format)) {
          do {
            precision = 10*precision + (*format - '0');
            format++;
          } while (isdigit (*format));
        }
      }
      /* Parse size. */
      switch (*format) {
        case 'h': case 'l': case 'L': case 'q':
        case 'j': case 'z': case 'Z': case 't':
          error(EXIT_FAILURE,0,
                /* TRANSLATORS: An error message.
                   The %s placeholder expands to a command-line option.  */
                _("%s argument: A format directive with a size is not allowed here."),
                param_name);
      }
      /* Parse end of directive. */
      switch (*format) {
        case '%':
          length = 1;
          break;
        case 'u': case 'o': case 'x': case 'X':
          if (*format == 'u') {
            length = (unsigned int) (sizeof (unsigned int) * CHAR_BIT
                                     * 0.30103 /* binary -> decimal */
                                    )
                     + 1; /* turn floor into ceil */
            if (length < precision)
              length = precision;
            length *= 2; /* estimate for FLAG_GROUP */
            length += 1; /* account for leading sign */
          } else if (*format == 'o') {
            length = (unsigned int) (sizeof (unsigned int) * CHAR_BIT
                                     * 0.333334 /* binary -> octal */
                                    )
                     + 1; /* turn floor into ceil */
            if (length < precision)
              length = precision;
            length += 1; /* account for leading sign */
          } else { /* 'x', 'X' */
            length = (unsigned int) (sizeof (unsigned int) * CHAR_BIT
                                     * 0.25 /* binary -> hexadecimal */
                                    )
                     + 1; /* turn floor into ceil */
            if (length < precision)
              length = precision;
            length += 2; /* account for leading sign or alternate form */
          }
          unnumbered_arg_count++;
          break;
        default:
          if (*format == '\0')
            error(EXIT_FAILURE,0,
                  /* TRANSLATORS: An error message.
                     The %s placeholder expands to a command-line option.  */
                  _("%s argument: The string ends in the middle of a directive."),
                  param_name);
          else if (c_isprint(*format))
            error(EXIT_FAILURE,0,
                  /* TRANSLATORS: An error message.
                     The %s placeholder expands to a command-line option.
                     The %c placeholder expands to an unknown format directive.  */
                  _("%s argument: The character '%c' is not a valid conversion specifier."),
                  param_name,*format);
          else
            error(EXIT_FAILURE,0,
                  /* TRANSLATORS: An error message.
                     The %s placeholder expands to a command-line option.  */
                  _("%s argument: The character that terminates the format directive is not a valid conversion specifier."),
                  param_name);
          abort(); /*NOTREACHED*/
      }
      format++;
      if (length < width)
        length = width;
      maxsize += length;
    } else
      maxsize++;
  }
  if (unnumbered_arg_count > 1)
    error(EXIT_FAILURE,0,
          /* TRANSLATORS: An error message.
             The %s placeholder expands to a command-line option.
             The %u placeholder expands to the number of arguments consumed by the format string.  */
          ngettext("%s argument: The format string consumes more than one argument: %u argument.",
                   "%s argument: The format string consumes more than one argument: %u arguments.",
                   unnumbered_arg_count),
          param_name,unnumbered_arg_count);
  return maxsize;
}

/* Format strings. */
static const char* ilseq_byte_subst;
static const char* ilseq_wchar_subst;
static const char* ilseq_unicode_subst;

/* Maximum result size for each format string. */
static size_t ilseq_byte_subst_size;
static size_t ilseq_wchar_subst_size;
static size_t ilseq_unicode_subst_size;

/* Buffer of size ilseq_byte_subst_size+1. */
static char* ilseq_byte_subst_buffer;
#if HAVE_WCHAR_T
/* Buffer of size ilseq_wchar_subst_size+1. */
static char* ilseq_wchar_subst_buffer;
#endif
/* Buffer of size ilseq_unicode_subst_size+1. */
static char* ilseq_unicode_subst_buffer;

/* Auxiliary variables for subst_mb_to_uc_fallback. */
/* Converter from locale encoding to UCS-4. */
static iconv_t subst_mb_to_uc_cd;
/* Buffer of size ilseq_byte_subst_size. */
static unsigned int* subst_mb_to_uc_temp_buffer;

static void subst_mb_to_uc_fallback
            (const char* inbuf, size_t inbufsize,
             void (*write_replacement) (const unsigned int *buf, size_t buflen,
                                        void* callback_arg),
             void* callback_arg,
             void* data)
{
  for (; inbufsize > 0; inbuf++, inbufsize--) {
    const char* inptr;
    size_t inbytesleft;
    char* outptr;
    size_t outbytesleft;
    sprintf(ilseq_byte_subst_buffer,
            ilseq_byte_subst, (unsigned int)(unsigned char)*inbuf);
    inptr = ilseq_byte_subst_buffer;
    inbytesleft = strlen(ilseq_byte_subst_buffer);
    outptr = (char*)subst_mb_to_uc_temp_buffer;
    outbytesleft = ilseq_byte_subst_size*sizeof(unsigned int);
    iconv(subst_mb_to_uc_cd,NULL,NULL,NULL,NULL);
    if (iconv(subst_mb_to_uc_cd, (ICONV_CONST char**)&inptr,&inbytesleft, &outptr,&outbytesleft)
        == (size_t)(-1)
        || iconv(subst_mb_to_uc_cd, NULL,NULL, &outptr,&outbytesleft)
           == (size_t)(-1))
      error(EXIT_FAILURE,0,
            /* TRANSLATORS: An error message.
               The %s placeholder expands to a piece of text, specified through --byte-subst.  */
            _("cannot convert byte substitution to Unicode: %s"),
            ilseq_byte_subst_buffer);
    if (!(outbytesleft%sizeof(unsigned int) == 0))
      abort();
    write_replacement(subst_mb_to_uc_temp_buffer,
                      ilseq_byte_subst_size-(outbytesleft/sizeof(unsigned int)),
                      callback_arg);
  }
}

/* Auxiliary variables for subst_uc_to_mb_fallback. */
/* Converter from locale encoding to target encoding. */
static iconv_t subst_uc_to_mb_cd;
/* Buffer of size ilseq_unicode_subst_size*4. */
static char* subst_uc_to_mb_temp_buffer;

static void subst_uc_to_mb_fallback
            (unsigned int code,
             void (*write_replacement) (const char *buf, size_t buflen,
                                        void* callback_arg),
             void* callback_arg,
             void* data)
{
  const char* inptr;
  size_t inbytesleft;
  char* outptr;
  size_t outbytesleft;
  sprintf(ilseq_unicode_subst_buffer, ilseq_unicode_subst, code);
  inptr = ilseq_unicode_subst_buffer;
  inbytesleft = strlen(ilseq_unicode_subst_buffer);
  outptr = subst_uc_to_mb_temp_buffer;
  outbytesleft = ilseq_unicode_subst_size*4;
  iconv(subst_uc_to_mb_cd,NULL,NULL,NULL,NULL);
  if (iconv(subst_uc_to_mb_cd, (ICONV_CONST char**)&inptr,&inbytesleft, &outptr,&outbytesleft)
      == (size_t)(-1)
      || iconv(subst_uc_to_mb_cd, NULL,NULL, &outptr,&outbytesleft)
         == (size_t)(-1))
    error(EXIT_FAILURE,0,
          /* TRANSLATORS: An error message.
             The %s placeholder expands to a piece of text, specified through --unicode-subst.  */
          _("cannot convert unicode substitution to target encoding: %s"),
          ilseq_unicode_subst_buffer);
  write_replacement(subst_uc_to_mb_temp_buffer,
                    ilseq_unicode_subst_size*4-outbytesleft,
                    callback_arg);
}

#if HAVE_WCHAR_T

/* Auxiliary variables for subst_mb_to_wc_fallback. */
/* Converter from locale encoding to wchar_t. */
static iconv_t subst_mb_to_wc_cd;
/* Buffer of size ilseq_byte_subst_size. */
static wchar_t* subst_mb_to_wc_temp_buffer;

static void subst_mb_to_wc_fallback
            (const char* inbuf, size_t inbufsize,
             void (*write_replacement) (const wchar_t *buf, size_t buflen,
                                        void* callback_arg),
             void* callback_arg,
             void* data)
{
  for (; inbufsize > 0; inbuf++, inbufsize--) {
    const char* inptr;
    size_t inbytesleft;
    char* outptr;
    size_t outbytesleft;
    sprintf(ilseq_byte_subst_buffer,
            ilseq_byte_subst, (unsigned int)(unsigned char)*inbuf);
    inptr = ilseq_byte_subst_buffer;
    inbytesleft = strlen(ilseq_byte_subst_buffer);
    outptr = (char*)subst_mb_to_wc_temp_buffer;
    outbytesleft = ilseq_byte_subst_size*sizeof(wchar_t);
    iconv(subst_mb_to_wc_cd,NULL,NULL,NULL,NULL);
    if (iconv(subst_mb_to_wc_cd, (ICONV_CONST char**)&inptr,&inbytesleft, &outptr,&outbytesleft)
        == (size_t)(-1)
        || iconv(subst_mb_to_wc_cd, NULL,NULL, &outptr,&outbytesleft)
           == (size_t)(-1))
      error(EXIT_FAILURE,0,
            /* TRANSLATORS: An error message.
               The %s placeholder expands to a piece of text, specified through --byte-subst.  */
            _("cannot convert byte substitution to wide string: %s"),
            ilseq_byte_subst_buffer);
    if (!(outbytesleft%sizeof(wchar_t) == 0))
      abort();
    write_replacement(subst_mb_to_wc_temp_buffer,
                      ilseq_byte_subst_size-(outbytesleft/sizeof(wchar_t)),
                      callback_arg);
  }
}

/* Auxiliary variables for subst_wc_to_mb_fallback. */
/* Converter from locale encoding to target encoding. */
static iconv_t subst_wc_to_mb_cd;
/* Buffer of size ilseq_wchar_subst_size*4.
   Hardcode factor 4, because MB_LEN_MAX is not reliable on some platforms. */
static char* subst_wc_to_mb_temp_buffer;

static void subst_wc_to_mb_fallback
            (wchar_t code,
             void (*write_replacement) (const char *buf, size_t buflen,
                                        void* callback_arg),
             void* callback_arg,
             void* data)
{
  const char* inptr;
  size_t inbytesleft;
  char* outptr;
  size_t outbytesleft;
  sprintf(ilseq_wchar_subst_buffer, ilseq_wchar_subst, (unsigned int) code);
  inptr = ilseq_wchar_subst_buffer;
  inbytesleft = strlen(ilseq_wchar_subst_buffer);
  outptr = subst_wc_to_mb_temp_buffer;
  outbytesleft = ilseq_wchar_subst_size*4;
  iconv(subst_wc_to_mb_cd,NULL,NULL,NULL,NULL);
  if (iconv(subst_wc_to_mb_cd, (ICONV_CONST char**)&inptr,&inbytesleft, &outptr,&outbytesleft)
      == (size_t)(-1)
      || iconv(subst_wc_to_mb_cd, NULL,NULL, &outptr,&outbytesleft)
         == (size_t)(-1))
    error(EXIT_FAILURE,0,
          /* TRANSLATORS: An error message.
             The %s placeholder expands to a piece of text, specified through --widechar-subst.  */
          _("cannot convert widechar substitution to target encoding: %s"),
          ilseq_wchar_subst_buffer);
  write_replacement(subst_wc_to_mb_temp_buffer,
                    ilseq_wchar_subst_size*4-outbytesleft,
                    callback_arg);
}

#else

#define subst_mb_to_wc_fallback NULL
#define subst_wc_to_mb_fallback NULL

#endif

/* Auxiliary variables for subst_mb_to_mb_fallback. */
/* Converter from locale encoding to target encoding. */
static iconv_t subst_mb_to_mb_cd;
/* Buffer of size ilseq_byte_subst_size*4. */
static char* subst_mb_to_mb_temp_buffer;

static void subst_mb_to_mb_fallback (const char* inbuf, size_t inbufsize)
{
  for (; inbufsize > 0; inbuf++, inbufsize--) {
    const char* inptr;
    size_t inbytesleft;
    char* outptr;
    size_t outbytesleft;
    sprintf(ilseq_byte_subst_buffer,
            ilseq_byte_subst, (unsigned int)(unsigned char)*inbuf);
    inptr = ilseq_byte_subst_buffer;
    inbytesleft = strlen(ilseq_byte_subst_buffer);
    outptr = subst_mb_to_mb_temp_buffer;
    outbytesleft = ilseq_byte_subst_size*4;
    iconv(subst_mb_to_mb_cd,NULL,NULL,NULL,NULL);
    if (iconv(subst_mb_to_mb_cd, (ICONV_CONST char**)&inptr,&inbytesleft, &outptr,&outbytesleft)
        == (size_t)(-1)
        || iconv(subst_mb_to_mb_cd, NULL,NULL, &outptr,&outbytesleft)
           == (size_t)(-1))
      error(EXIT_FAILURE,0,
            /* TRANSLATORS: An error message.
               The %s placeholder expands to a piece of text, specified through --byte-subst.  */
            _("cannot convert byte substitution to target encoding: %s"),
            ilseq_byte_subst_buffer);
    fwrite(subst_mb_to_mb_temp_buffer,1,ilseq_byte_subst_size*4-outbytesleft,
           stdout);
  }
}

/* ========================================================================= */

/* Error messages during conversion.  */

static void conversion_error_EILSEQ (const char* infilename)
{
  fflush(stdout);
  if (column > 0)
    putc('\n',stderr);
  error(0,0,
        /* TRANSLATORS: An error message.
           The placeholders expand to the input file name, a line number, and a column number.  */
        _("%s:%u:%u: cannot convert"),
        infilename,line,column);
}

static void conversion_error_EINVAL (const char* infilename)
{
  fflush(stdout);
  if (column > 0)
    putc('\n',stderr);
  error(0,0,
        /* TRANSLATORS: An error message.
           The placeholders expand to the input file name, a line number, and a column number.
           A "shift sequence" is a sequence of bytes that changes the state of the converter;
           this concept exists only for "stateful" encodings like ISO-2022-JP.  */
        _("%s:%u:%u: incomplete character or shift sequence"),
        infilename,line,column);
}

static void conversion_error_other (int errnum, const char* infilename)
{
  fflush(stdout);
  if (column > 0)
    putc('\n',stderr);
  error(0,errnum,
        /* TRANSLATORS: The first part of an error message.
           It is followed by a colon and a detail message.
           The placeholders expand to the input file name, a line number, and a column number.  */
        _("%s:%u:%u"),
        infilename,line,column);
}

/* Convert the input given in infile.  */

static int convert (iconv_t cd, int infile, const char* infilename, _GL_UNUSED const char* tocode)
{
  char inbuf[4096+4096];
  size_t inbufrest = 0;
  int infile_error = 0;
  char initial_outbuf[4096];
  char *outbuf = initial_outbuf;
  size_t outbufsize = sizeof(initial_outbuf);
  int status = 0;

#if O_BINARY
  SET_BINARY(infile);
#endif
#ifdef __MVS__
  /* Turn off z/OS auto-conversion.  */
  struct f_cnvrt req = {SETCVTOFF, 0, 0};
  fcntl(infile, F_CONTROL_CVT, &req);
#endif
  line = 1; column = 0;
  iconv(cd,NULL,NULL,NULL,NULL);
  for (;;) {
    size_t inbufsize;
    /* Transfer the accumulated output to its destination, in case the
       safe_read() call will block. */
    fflush(stdout);
    inbufsize = safe_read(infile,inbuf+4096,4096);
    if (inbufsize == 0 || inbufsize == SAFE_READ_ERROR) {
      infile_error = (inbufsize == SAFE_READ_ERROR ? errno : 0);
      if (inbufrest == 0)
        break;
      else {
        if (ilseq_byte_subst != NULL)
          subst_mb_to_mb_fallback(inbuf+4096-inbufrest, inbufrest);
        if (!silent)
          conversion_error_EINVAL(infilename);
        status = 1;
        goto done;
      }
    } else {
      const char* inptr = inbuf+4096-inbufrest;
      size_t insize = inbufrest+inbufsize;
      inbufrest = 0;
      while (insize > 0) {
        char* outptr = outbuf;
        size_t outsize = outbufsize;
        size_t res = iconv(cd,(ICONV_CONST char**)&inptr,&insize,&outptr,&outsize);
        if (outptr != outbuf) {
          int saved_errno = errno;
          if (fwrite(outbuf,1,outptr-outbuf,stdout) < outptr-outbuf) {
            status = 1;
            goto done;
          }
          errno = saved_errno;
        }
        if (res == (size_t)(-1)) {
          if (errno == EILSEQ) {
            if (discard_unconvertible == 1) {
              int one = 1;
              iconvctl(cd,ICONV_SET_DISCARD_ILSEQ,&one);
              discard_unconvertible = 2;
              status = 1;
            } else {
              if (!silent)
                conversion_error_EILSEQ(infilename);
              status = 1;
              goto done;
            }
          } else if (errno == EINVAL) {
            if (inbufsize == 0 || insize > 4096) {
              if (!silent)
                conversion_error_EINVAL(infilename);
              status = 1;
              goto done;
            } else {
              inbufrest = insize;
              if (insize > 0) {
                /* Like memcpy(inbuf+4096-insize,inptr,insize), except that
                   we cannot use memcpy here, because source and destination
                   regions may overlap. */
                char* restptr = inbuf+4096-insize;
                do { *restptr++ = *inptr++; } while (--insize > 0);
              }
              break;
            }
          } else if (errno == E2BIG) {
            if (outptr==outbuf) {
              /* outbuf is too small. Double its size. */
              if (outbuf != initial_outbuf)
                free(outbuf);
              outbufsize = 2*outbufsize;
              if (outbufsize==0) /* integer overflow? */
                xalloc_die();
              outbuf = (char*)xmalloc(outbufsize);
            }
          } else {
            if (!silent)
              conversion_error_other(errno,infilename);
            status = 1;
            goto done;
          }
        }
      }
    }
  }
  for (;;) {
    char* outptr = outbuf;
    size_t outsize = outbufsize;
    size_t res = iconv(cd,NULL,NULL,&outptr,&outsize);
    if (outptr != outbuf) {
      int saved_errno = errno;
      if (fwrite(outbuf,1,outptr-outbuf,stdout) < outptr-outbuf) {
        status = 1;
        goto done;
      }
      errno = saved_errno;
    }
    if (res == (size_t)(-1)) {
      if (errno == EILSEQ) {
        if (discard_unconvertible == 1) {
          int one = 1;
          iconvctl(cd,ICONV_SET_DISCARD_ILSEQ,&one);
          discard_unconvertible = 2;
          status = 1;
        } else {
          if (!silent)
            conversion_error_EILSEQ(infilename);
          status = 1;
          goto done;
        }
      } else if (errno == EINVAL) {
        if (!silent)
          conversion_error_EINVAL(infilename);
        status = 1;
        goto done;
      } else if (errno == E2BIG) {
        if (outptr==outbuf) {
          /* outbuf is too small. Double its size. */
          if (outbuf != initial_outbuf)
            free(outbuf);
          outbufsize = 2*outbufsize;
          if (outbufsize==0) /* integer overflow? */
            xalloc_die();
          outbuf = (char*)xmalloc(outbufsize);
        }
      } else {
        if (!silent)
          conversion_error_other(errno,infilename);
        status = 1;
        goto done;
      }
    } else
      break;
  }
  if (infile_error) {
    fflush(stdout);
    if (column > 0)
      putc('\n',stderr);
    error(0,infile_error,
          /* TRANSLATORS: An error message.
             The placeholder expands to the input file name.  */
          _("%s: I/O error"),
          infilename);
    status = 1;
    goto done;
  }
 done:
#ifdef __MVS__
  if (!status) {
    status = tagfile(fileno(stdout), tocode);
  }
#endif
  if (outbuf != initial_outbuf)
    free(outbuf);
  return status;
}

/* ========================================================================= */

int main (int argc, char* argv[])
{
  const char* fromcode = NULL;
  const char* tocode = NULL;
  int do_list = 0;
  iconv_t cd;
  struct iconv_fallbacks fallbacks;
  struct iconv_hooks hooks;
  int i;
  int status;

  set_program_name (argv[0]);
#if HAVE_SETLOCALE
  /* Needed for the locale dependent encodings, "char" and "wchar_t",
     and for gettext. */
  setlocale(LC_CTYPE,"");
#if ENABLE_NLS
  /* Needed for gettext. */
  setlocale(LC_MESSAGES,"");
#endif
#endif
#if ENABLE_NLS
  bindtextdomain("libiconv",relocate(LOCALEDIR));
#endif
  textdomain("libiconv");
  /* No need to invoke the gnulib function stdopen() here, because
     (1) the only file descriptor allocations done by this program are
         fopen(...,"r"),
     (2) when such fopen() calls occur, stdin is not used,
     hence
     - when an fopen() call happens to open fd 0, it is harmless, by (2),
     - when an fopen() call happens to open fd 1 or 2, writing to
       stdout or stderr will produce an error, by (1). */

  for (i = 1; i < argc;) {
    size_t len = strlen(argv[i]);
    if (!strcmp(argv[i],"--")) {
      i++;
      break;
    }
    if (!strcmp(argv[i],"-f")
        /* --f ... --from-code */
        || (len >= 3 && len <= 11 && !strncmp(argv[i],"--from-code",len))
        /* --from-code=... */
        || (len >= 12 && !strncmp(argv[i],"--from-code=",12))) {
      if (len < 12)
        if (i == argc-1) usage(1);
      if (fromcode != NULL) usage(1);
      if (len < 12) {
        fromcode = argv[i+1];
        i += 2;
      } else {
        fromcode = argv[i]+12;
        i++;
      }
      continue;
    }
    if (!strcmp(argv[i],"-t")
        /* --t ... --to-code */
        || (len >= 3 && len <= 9 && !strncmp(argv[i],"--to-code",len))
        /* --from-code=... */
        || (len >= 10 && !strncmp(argv[i],"--to-code=",10))) {
      if (len < 10)
        if (i == argc-1) usage(1);
      if (tocode != NULL) usage(1);
      if (len < 10) {
        tocode = argv[i+1];
        i += 2;
      } else {
        tocode = argv[i]+10;
        i++;
      }
      continue;
    }
    if (!strcmp(argv[i],"-l")
        /* --l ... --list */
        || (len >= 3 && len <= 6 && !strncmp(argv[i],"--list",len))) {
      do_list = 1;
      i++;
      continue;
    }
    if (/* --by ... --byte-subst */
        (len >= 4 && len <= 12 && !strncmp(argv[i],"--byte-subst",len))
        /* --byte-subst=... */
        || (len >= 13 && !strncmp(argv[i],"--byte-subst=",13))) {
      if (len < 13) {
        if (i == argc-1) usage(1);
        ilseq_byte_subst = argv[i+1];
        i += 2;
      } else {
        ilseq_byte_subst = argv[i]+13;
        i++;
      }
      ilseq_byte_subst_size =
        check_subst_formatstring(ilseq_byte_subst, "--byte-subst");
      continue;
    }
    if (/* --w ... --widechar-subst */
        (len >= 3 && len <= 16 && !strncmp(argv[i],"--widechar-subst",len))
        /* --widechar-subst=... */
        || (len >= 17 && !strncmp(argv[i],"--widechar-subst=",17))) {
      if (len < 17) {
        if (i == argc-1) usage(1);
        ilseq_wchar_subst = argv[i+1];
        i += 2;
      } else {
        ilseq_wchar_subst = argv[i]+17;
        i++;
      }
      ilseq_wchar_subst_size =
        check_subst_formatstring(ilseq_wchar_subst, "--widechar-subst");
      continue;
    }
    if (/* --u ... --unicode-subst */
        (len >= 3 && len <= 15 && !strncmp(argv[i],"--unicode-subst",len))
        /* --unicode-subst=... */
        || (len >= 16 && !strncmp(argv[i],"--unicode-subst=",16))) {
      if (len < 16) {
        if (i == argc-1) usage(1);
        ilseq_unicode_subst = argv[i+1];
        i += 2;
      } else {
        ilseq_unicode_subst = argv[i]+16;
        i++;
      }
      ilseq_unicode_subst_size =
        check_subst_formatstring(ilseq_unicode_subst, "--unicode-subst");
      continue;
    }
    if /* --s ... --silent */
       (len >= 3 && len <= 8 && !strncmp(argv[i],"--silent",len)) {
      silent = 1;
      i++;
      continue;
    }
    if /* --h ... --help */
       (len >= 3 && len <= 6 && !strncmp(argv[i],"--help",len)) {
      usage(0);
    }
    if /* --v ... --version */
       (len >= 3 && len <= 9 && !strncmp(argv[i],"--version",len)) {
      print_version();
    }
#if O_BINARY
    /* Backward compatibility with iconv <= 1.9.1. */
    if /* --bi ... --binary */
       (len >= 4 && len <= 8 && !strncmp(argv[i],"--binary",len)) {
      i++;
      continue;
    }
#endif
    if (argv[i][0] == '-') {
      const char *option = argv[i] + 1;
      if (*option == '\0')
        usage(1);
      for (; *option; option++)
        switch (*option) {
          case 'c': discard_unconvertible = 1; break;
          case 's': silent = 1; break;
          default: usage(1);
        }
      i++;
      continue;
    }
    break;
  }
  if (do_list) {
    if (i != 2 || i != argc)
      usage(1);
    iconvlist(print_one,NULL);
    status = 0;
  } else {
#if O_BINARY
    SET_BINARY(fileno(stdout));
#endif
    if (fromcode == NULL)
      fromcode = "char";
    if (tocode == NULL)
      tocode = "char";
    cd = iconv_open(tocode,fromcode);
    if (cd == (iconv_t)(-1)) {
      if (iconv_open("UCS-4",fromcode) == (iconv_t)(-1))
        error(0,0,
              /* TRANSLATORS: An error message.
                 The placeholder expands to the encoding name, specified through --from-code.  */
              _("conversion from %s unsupported"),
              fromcode);
      else if (iconv_open(tocode,"UCS-4") == (iconv_t)(-1))
        error(0,0,
              /* TRANSLATORS: An error message.
                 The placeholder expands to the encoding name, specified through --to-code.  */
              _("conversion to %s unsupported"),
              tocode);
      else
        error(0,0,
              /* TRANSLATORS: An error message.
                 The placeholders expand to the encoding names, specified through --from-code and --to-code, respectively.  */
              _("conversion from %s to %s unsupported"),
              fromcode,tocode);
      error(EXIT_FAILURE,0,
            /* TRANSLATORS: Additional advice after an error message.
               The %s placeholder expands to the program name.  */
            _("try '%s -l' to get the list of supported encodings"),
            program_name);
    }
    /* For EBCDIC encodings, determine how to map 0x15 (which encodes the
       "newline function", see the Unicode standard, chapter 5).  */
    const char *envvar_value = getenv("ICONV_EBCDIC_ZOS_UNIX");
    if (envvar_value != NULL && envvar_value[0] != '\0') {
      unsigned int surface;
      iconvctl(cd, ICONV_GET_FROM_SURFACE, &surface);
      surface |= ICONV_SURFACE_EBCDIC_ZOS_UNIX;
      iconvctl(cd, ICONV_SET_FROM_SURFACE, &surface);
      iconvctl(cd, ICONV_GET_TO_SURFACE, &surface);
      surface |= ICONV_SURFACE_EBCDIC_ZOS_UNIX;
      iconvctl(cd, ICONV_SET_TO_SURFACE, &surface);
    }
    /* Look at fromcode and tocode, to determine whether character widths
       should be determined according to legacy CJK conventions. */
    cjkcode = iconv_canonicalize(tocode);
    if (!is_cjk_encoding(cjkcode))
      cjkcode = iconv_canonicalize(fromcode);
    /* Set up fallback routines for handling impossible conversions. */
    if (ilseq_byte_subst != NULL)
      ilseq_byte_subst_buffer = (char*)xmalloc((ilseq_byte_subst_size+1)*sizeof(char));
    if (!discard_unconvertible) {
      #if HAVE_WCHAR_T
      if (ilseq_wchar_subst != NULL)
        ilseq_wchar_subst_buffer = (char*)xmalloc((ilseq_wchar_subst_size+1)*sizeof(char));
      #endif
      if (ilseq_unicode_subst != NULL)
        ilseq_unicode_subst_buffer = (char*)xmalloc((ilseq_unicode_subst_size+1)*sizeof(char));
      if (ilseq_byte_subst != NULL) {
        subst_mb_to_uc_cd = iconv_open("UCS-4-INTERNAL","char");
        subst_mb_to_uc_temp_buffer = (unsigned int*)xmalloc(ilseq_byte_subst_size*sizeof(unsigned int));
        #if HAVE_WCHAR_T
        subst_mb_to_wc_cd = iconv_open("wchar_t","char");
        subst_mb_to_wc_temp_buffer = (wchar_t*)xmalloc(ilseq_byte_subst_size*sizeof(wchar_t));
        #endif
        subst_mb_to_mb_cd = iconv_open(tocode,"char");
        subst_mb_to_mb_temp_buffer = (char*)xmalloc(ilseq_byte_subst_size*4);
      }
      #if HAVE_WCHAR_T
      if (ilseq_wchar_subst != NULL) {
        subst_wc_to_mb_cd = iconv_open(tocode,"char");
        subst_wc_to_mb_temp_buffer = (char*)xmalloc(ilseq_wchar_subst_size*4);
      }
      #endif
      if (ilseq_unicode_subst != NULL) {
        subst_uc_to_mb_cd = iconv_open(tocode,"char");
        subst_uc_to_mb_temp_buffer = (char*)xmalloc(ilseq_unicode_subst_size*4);
      }
      fallbacks.mb_to_uc_fallback =
        (ilseq_byte_subst != NULL ? subst_mb_to_uc_fallback : NULL);
      fallbacks.uc_to_mb_fallback =
        (ilseq_unicode_subst != NULL ? subst_uc_to_mb_fallback : NULL);
      fallbacks.mb_to_wc_fallback =
        (ilseq_byte_subst != NULL ? subst_mb_to_wc_fallback : NULL);
      fallbacks.wc_to_mb_fallback =
        (ilseq_wchar_subst != NULL ? subst_wc_to_mb_fallback : NULL);
      fallbacks.data = NULL;
      iconvctl(cd, ICONV_SET_FALLBACKS, &fallbacks);
    }
    /* Set up hooks for updating the line and column position. */
    hooks.uc_hook = update_line_column;
    hooks.wc_hook = NULL;
    hooks.data = NULL;
    iconvctl(cd, ICONV_SET_HOOKS, &hooks);
    if (i == argc)
      status = convert(cd,fileno(stdin),
                       /* TRANSLATORS: A filename substitute denoting standard input.  */
                       _("(stdin)"),
                       tocode);
    else {
      status = 0;
      for (; i < argc; i++) {
        const char* infilename = argv[i];
        FILE* infile = fopen(infilename,"r");
        if (infile == NULL) {
          int saved_errno = errno;
          error(0,saved_errno,
                /* TRANSLATORS: The first part of an error message.
                   It is followed by a colon and a detail message.
                   The %s placeholder expands to the input file name.  */
                _("%s"),
                infilename);
          status = 1;
        } else {
          status |= convert(cd,fileno(infile),infilename,tocode);
          fclose(infile);
        }
      }
    }
    iconv_close(cd);
  }
  if (ferror(stdout) || fclose(stdout)) {
    error(0,0,
          /* TRANSLATORS: An error message.  */
          _("I/O error"));
    status = 1;
  }
  exit(status);
}