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[coreutils.git] / src / sort.c

/* sort - sort lines of text (with all kinds of options).
   Copyright (C) 88, 1991-1999 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 2, 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Written December 1988 by Mike Haertel.
   The author may be reached (Email) at the address mike@gnu.ai.mit.edu,
   or (US mail) as Mike Haertel c/o Free Software Foundation.

   Ørn E. Hansen added NLS support in 1997.  */

#include <config.h>

#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <assert.h>
#include "system.h"
#include "long-options.h"
#include "error.h"
#include "xstrtod.h"
#include "xalloc.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "sort"

#define AUTHORS "Mike Haertel"

#if defined ENABLE_NLS && HAVE_LANGINFO_H
# include <langinfo.h>
#endif

#if HAVE_PATHCONF && defined _PC_NAME_MAX
# define NAME_MAX_IN_DIR(Dir) pathconf (Dir, _PC_NAME_MAX)
#else
# define NAME_MAX_IN_DIR(Dir) 255
#endif

char *xstrdup ();

/* Undefine, to avoid warning about redefinition on some systems.  */
#undef min
#define min(a, b) ((a) < (b) ? (a) : (b))
#undef max
#define max(a, b) ((a) > (b) ? (a) : (b))

#define UCHAR_LIM (UCHAR_MAX + 1)
#define UCHAR(c) ((unsigned char) (c))

#ifndef DEFAULT_TMPDIR
# define DEFAULT_TMPDIR "/tmp"
#endif

/* Use this as exit status in case of error, not EXIT_FAILURE.  This
   is necessary because EXIT_FAILURE is usually 1 and POSIX requires
   that sort exit with status 1 IFF invoked with -c and the input is
   not properly sorted.  Any other irregular exit must exit with a
   status code greater than 1.  */
#define SORT_FAILURE 2

#define FLOATING_POINT  '.'
#define FLOATING_COMMA  ','
#define NEGATION_SIGN   '-'
#define NUMERIC_ZERO    '0'

#ifdef ENABLE_NLS
# define NLS_MEMCMP(S1, S2, Len) strncoll (S1, S2, Len)
# define NLS_STRNCMP(S1, S2, Len) strncoll_s2_readonly (S1, S2, Len)
#else
# define NLS_MEMCMP(S1, S2, Len) memcmp (S1, S2, Len)
# define NLS_STRNCMP(S1, S2, Len) strncmp (S1, S2, Len)
#endif

#ifdef ENABLE_NLS

static unsigned char decimal_point;
static unsigned char th_sep;
static char *nls_grouping;

/* This is "C" locale, need another? */
static int need_locale = 0;

/* Should we look for decimal point? */
static int nls_fraction_found = 1;

/* Look for month notations in text? */
static int nls_month_found = 1;

#else

# define decimal_point FLOATING_POINT

#endif

/* If native language support is requested, make a 1-1 map to the
   locale character map, otherwise ensure normal behavior.  */
#ifdef ENABLE_NLS

/* 12 months in a year */
# define NLS_NUM_MONTHS 12

/* Maximum number of elements, to allocate per allocation unit  */
# define NLS_MAX_GROUPS 8

/* A string with one character, to enforce char collation */
# define NLS_ONE_CHARACTER_STRING " "

#endif

/* The kind of blanks for '-b' to skip in various options. */
enum blanktype { bl_start, bl_end, bl_both };

/* The character marking end of line. Default to \n. */
int eolchar = '\n';

/* Lines are held in core as counted strings. */
struct line
{
  char *text;                   /* Text of the line. */
  int length;                   /* Length not including final newline. */
  char *keybeg;                 /* Start of first key. */
  char *keylim;                 /* Limit of first key. */
};

/* Arrays of lines. */
struct lines
{
  struct line *lines;           /* Dynamically allocated array of lines. */
  int used;                     /* Number of slots used. */
  int alloc;                    /* Number of slots allocated. */
  int limit;                    /* Max number of slots to allocate.  */
};

/* Input buffers. */
struct buffer
{
  char *buf;                    /* Dynamically allocated buffer. */
  int used;                     /* Number of bytes used. */
  int alloc;                    /* Number of bytes allocated. */
  int left;                     /* Number of bytes left after line parsing. */
};

struct keyfield
{
  int sword;                    /* Zero-origin 'word' to start at. */
  int schar;                    /* Additional characters to skip. */
  int skipsblanks;              /* Skip leading white space at start. */
  int eword;                    /* Zero-origin first word after field. */
  int echar;                    /* Additional characters in field. */
  int skipeblanks;              /* Skip trailing white space at finish. */
  int *ignore;                  /* Boolean array of characters to ignore. */
  char *translate;              /* Translation applied to characters. */
  int numeric;                  /* Flag for numeric comparison.  Handle
                                   strings of digits with optional decimal
                                   point, but no exponential notation. */
  int general_numeric;          /* Flag for general, numeric comparison.
                                   Handle numbers in exponential notation. */
  int month;                    /* Flag for comparison by month name. */
  int reverse;                  /* Reverse the sense of comparison. */
  struct keyfield *next;        /* Next keyfield to try. */
};

struct month
{
  char *name;
  int val;
};

/* The name this program was run with. */
char *program_name;

/* Table of white space. */
static int blanks[UCHAR_LIM];

/* Table of non-printing characters. */
static int nonprinting[UCHAR_LIM];

/* Table of non-dictionary characters (not letters, digits, or blanks). */
static int nondictionary[UCHAR_LIM];

/* Translation table folding lower case to upper. */
static char fold_toupper[UCHAR_LIM];

/* Table mapping 3-letter month names to integers.
   Alphabetic order allows binary search. */
static const struct month us_monthtab[] =
{
  {"APR", 4},
  {"AUG", 8},
  {"DEC", 12},
  {"FEB", 2},
  {"JAN", 1},
  {"JUL", 7},
  {"JUN", 6},
  {"MAR", 3},
  {"MAY", 5},
  {"NOV", 11},
  {"OCT", 10},
  {"SEP", 9}
};

#ifdef ENABLE_NLS

/* Locale may have a different idea of month names   */
static struct month nls_monthtab[NLS_NUM_MONTHS];
static int nls_months_collide[NLS_NUM_MONTHS + 1];

/* Numeric keys, to search for numeric format */
struct nls_keyfield
{
  struct keyfield *key;
  struct nls_keyfield *next;
};

static struct nls_keyfield *nls_keyhead = NULL;

#endif

/* Which month table to use in the program, default C */
static const struct month *monthtab = us_monthtab;

/* During the merge phase, the number of files to merge at once. */
#define NMERGE 16

/* Initial buffer size for in core sorting.  Will not grow unless a
   line longer than this is seen. */
static int sortalloc = 512 * 1024;

/* Initial buffer size for in core merge buffers.  Bear in mind that
   up to NMERGE * mergealloc bytes may be allocated for merge buffers. */
static int mergealloc = 16 * 1024;

/* Guess of average line length. */
static int linelength = 30;

/* Maximum number of elements for the array(s) of struct line's, in bytes.  */
#define LINEALLOC (256 * 1024)

/* Directory in which any temporary files are to be created. */
static char *temp_dir;

/* Flag to reverse the order of all comparisons. */
static int reverse;

/* Flag for stable sort.  This turns off the last ditch bytewise
   comparison of lines, and instead leaves lines in the same order
   they were read if all keys compare equal.  */
static int stable;

/* Tab character separating fields.  If NUL, then fields are separated
   by the empty string between a non-whitespace character and a whitespace
   character. */
static char tab;

/* Flag to remove consecutive duplicate lines from the output.
   Only the last of a sequence of equal lines will be output. */
static int unique;

/* Nonzero if any of the input files are the standard input. */
static int have_read_stdin;

/* Lists of key field comparisons to be tried. */
static struct keyfield keyhead;

void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
             program_name);
  else
    {
      printf (_("\
Usage: %s [OPTION]... [FILE]...\n\
"),
              program_name);
      printf (_("\
Write sorted concatenation of all FILE(s) to standard output.\n\
\n\
  +POS1 [-POS2]    start a key at POS1, end it before POS2\n\
  -b               ignore leading blanks in sort fields or keys\n\
  -c               check if given files already sorted, do not sort\n\
  -d               consider only [a-zA-Z0-9 ] characters in keys\n\
  -f               fold lower case to upper case characters in keys\n\
  -g               compare according to general numerical value, imply -b\n\
  -i               consider only [\\040-\\0176] characters in keys\n\
  -k POS1[,POS2]   same as +POS1 [-POS2], but all positions counted from 1\n\
  -m               merge already sorted files, do not sort\n\
  -M               compare (unknown) < `JAN' < ... < `DEC', imply -b\n\
  -n               compare according to string numerical value, imply -b\n\
  -o FILE          write result on FILE instead of standard output\n\
  -r               reverse the result of comparisons\n\
  -s               stabilize sort by disabling last resort comparison\n\
  -t SEP           use SEParator instead of non- to whitespace transition\n\
  -T DIRECTORY     use DIRECTORY for temporary files, not $TMPDIR or %s\n\
  -u               with -c, check for strict ordering;\n\
                   with -m, only output the first of an equal sequence\n\
  -z               end lines with 0 byte, not newline, for find -print0\n\
      --help       display this help and exit\n\
      --version    output version information and exit\n\
\n\
POS is F[.C][OPTS], where F is the field number and C the character\n\
position in the field, both counted from zero.  OPTS is made up of one\n\
or more of Mbdfinr, this effectively disable global -Mbdfinr settings\n\
for that key.  If no key given, use the entire line as key.  With no\n\
FILE, or when FILE is -, read standard input.\n\
")
              , DEFAULT_TMPDIR);
      puts (_("\nReport bugs to <bug-textutils@gnu.org>."));
    }
  /* Don't use EXIT_FAILURE here in case it is defined to be 1.
     POSIX requires that sort return 1 IFF invoked with -c and
     the input is not properly sorted.  */
  assert (status == 0 || status == SORT_FAILURE);
  exit (status);
}

/* The list of temporary files. */
static struct tempnode
{
  char *name;
  struct tempnode *next;
} temphead;

/* Clean up any remaining temporary files. */

static void
cleanup (void)
{
  struct tempnode *node;

  for (node = temphead.next; node; node = node->next)
    unlink (node->name);
}

static FILE *
xtmpfopen (const char *file)
{
  FILE *fp;
  int fd;

  /*  Open temporary file exclusively, to foil a common
      denial-of-service attack.  */
  fd = open (file, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 0600);
  if (fd < 0 || (fp = fdopen (fd, "w")) == NULL)
    {
      error (0, errno, "%s", file);
      cleanup ();
      exit (SORT_FAILURE);
    }

  return fp;
}

static FILE *
xfopen (const char *file, const char *how)
{
  FILE *fp;

  if (STREQ (file, "-"))
    {
      fp = stdin;
    }
  else
    {
      if ((fp = fopen (file, how)) == NULL)
        {
          error (0, errno, "%s", file);
          cleanup ();
          exit (SORT_FAILURE);
        }
    }

  if (fp == stdin)
    have_read_stdin = 1;
  return fp;
}

static void
xfclose (FILE *fp)
{
  if (fp == stdin)
    {
      /* Allow reading stdin from tty more than once. */
      if (feof (fp))
        clearerr (fp);
    }
  else if (fp == stdout)
    {
      if (fflush (fp) != 0)
        {
          error (0, errno, _("flushing file"));
          cleanup ();
          exit (SORT_FAILURE);
        }
    }
  else
    {
      if (fclose (fp) != 0)
        {
          error (0, errno, _("error closing file"));
          cleanup ();
          exit (SORT_FAILURE);
        }
    }
}

static void
write_bytes (const char *buf, size_t n_bytes, FILE *fp)
{
  if (fwrite (buf, 1, n_bytes, fp) != n_bytes)
    {
      error (0, errno, _("write error"));
      cleanup ();
      exit (SORT_FAILURE);
    }
}

/* Return a name for a temporary file. */

static char *
tempname (void)
{
  static unsigned int seq;
  int len = strlen (temp_dir);
  char *name = xmalloc (len + 1 + sizeof ("sort") - 1 + 5 + 5 + 1);
  int long_file_names = NAME_MAX_IN_DIR (temp_dir) > 12;
  struct tempnode *node;

  /* If long filenames aren't supported, we cannot use filenames
     longer than 8+3 and still assume they are unique.  */
  if (long_file_names)
    sprintf (name,
             "%s%ssort%5.5d%5.5d",
             temp_dir,
             (len && temp_dir[len - 1] != '/') ? "/" : "",
             (unsigned int) getpid () & 0xffff, seq);
  else
    sprintf (name, "%s%ss%5.5d%2.2d.%3.3d",
             temp_dir,
             (len && temp_dir[len - 1] != '/') ? "/" : "",
             (unsigned int) getpid () & 0xffff, seq / 1000, seq % 1000);

  ++seq;

  /* Make sure that SEQ's value fits in 5 digits if temp_dir is on
     an 8.3 filesystem.  */
  if (!long_file_names && seq >= 100000)
    seq = 0;

  node = (struct tempnode *) xmalloc (sizeof (struct tempnode));
  node->name = name;
  node->next = temphead.next;
  temphead.next = node;
  return name;
}

/* Search through the list of temporary files for NAME;
   remove it if it is found on the list. */

static void
zaptemp (const char *name)
{
  struct tempnode *node, *temp;

  for (node = &temphead; node->next; node = node->next)
    if (STREQ (name, node->next->name))
      break;
  if (node->next)
    {
      temp = node->next;
      unlink (temp->name);
      free (temp->name);
      node->next = temp->next;
      free ((char *) temp);
    }
}

#ifdef ENABLE_NLS
/* Initialize the character class tables. */

static int
nls_sort_month_comp (const void *m1, const void *m2)
{
  return strcoll (((const struct month *) m1)->name,
                  ((const struct month *) m2)->name);
}

/* Do collation on strings S1 and S2, but for at most L characters.
   we use the fact, that we KNOW that LEN is the min of the two lengths */
static int
strncoll (char *s1, char *s2, int len)
{
  register int diff;

  if (need_locale)
    {
      /* Emulate a strncoll function, by forcing strcoll to compare
         only the first LEN characters in each string. */
      register unsigned char n1 = s1[len];
      register unsigned char n2 = s2[len];

      s1[len] = s2[len] = 0;
      diff = strcoll (s1, s2);
      s1[len] = n1;
      s2[len] = n2;
    }
  else
    {
      diff = memcmp (s1, s2, len);
    }

  return diff;
}

/* Do collation on strings S1 and S2, but for at most L characters.
   Use the fact, that we KNOW that S2 is the shorter string and has
   length LEN.  */
static int
strncoll_s2_readonly (char *s1, const char *s2, int len)
{
  register int diff;

  assert (len == strlen (s2));
  assert (len <= strlen (s1));

  if (need_locale)
    {
      /* Emulate a strncoll function, by forcing strcoll to compare
         only the first LEN characters in each string. */
      register unsigned char n1 = s1[len];

      s1[len] = 0;
      diff = strcoll (s1, s2);
      s1[len] = n1;
    }
  else
    {
      diff = memcmp (s1, s2, len);
    }

  return diff;
}

#endif /* NLS */

static void
inittables (void)
{
  int i;

  for (i = 0; i < UCHAR_LIM; ++i)
    {
      if (ISBLANK (i))
        blanks[i] = 1;
      if (!ISPRINT (i))
        nonprinting[i] = 1;
      if (!ISALNUM (i) && !ISBLANK (i))
        nondictionary[i] = 1;
      if (ISLOWER (i))
        fold_toupper[i] = toupper (i);
      else
        fold_toupper[i] = i;
    }

#if defined ENABLE_NLS && HAVE_NL_LANGINFO
  /* If We're not in the "C" locale, read in different names for months. */
  if (need_locale)
    {
      nls_months_collide[0] = 1;        /* if an error, look again       */
      for (i = 0; i < NLS_NUM_MONTHS; i++)
        {
          char *s;
          size_t s_len;
          int j;

          s = (char *) nl_langinfo (ABMON_1 + us_monthtab[i].val - 1);
          s_len = strlen (s);
          nls_monthtab[i].name = (char *) xmalloc (s_len + 1);
          nls_monthtab[i].val = us_monthtab[i].val;

          /* Be careful: abreviated month names
             may be longer than the usual 3 characters.  */
          for (j = 0; j < s_len; j++)
            nls_monthtab[i].name[j] = fold_toupper[UCHAR (s[j])];
          nls_monthtab[i].name[j] = '\0';

          nls_months_collide[nls_monthtab[i].val] = 0;
          for (j = 0; j < NLS_NUM_MONTHS; ++j)
            {
              if (STREQ (nls_monthtab[i].name, us_monthtab[i].name))
                {
                  /* There are indeed some month names in English which
                     collide with the NLS name.  */
                  nls_months_collide[nls_monthtab[i].val] = 1;
                  break;
                }
            }
        }
      /* Now quicksort the month table (should be sorted already!).
         However, another locale doesn't rule out the possibility
         of a different order of month names. */
      qsort ((void *) nls_monthtab, NLS_NUM_MONTHS,
             sizeof (struct month), nls_sort_month_comp);
      monthtab = nls_monthtab;
    }
#endif /* NLS */
}

/* Initialize BUF, allocating ALLOC bytes initially. */

static void
initbuf (struct buffer *buf, int alloc)
{
  buf->alloc = alloc;
  buf->buf = xmalloc (buf->alloc);
  buf->used = buf->left = 0;
}

/* Fill BUF reading from FP, moving buf->left bytes from the end
   of buf->buf to the beginning first.  If EOF is reached and the
   file wasn't terminated by a newline, supply one.  Return a count
   of bytes buffered. */

static int
fillbuf (struct buffer *buf, FILE *fp)
{
  int cc;

  memmove (buf->buf, buf->buf + buf->used - buf->left, buf->left);
  buf->used = buf->left;

  while (!feof (fp) && (buf->used == 0
                        || !memchr (buf->buf, eolchar, buf->used)))
    {
      if (buf->used == buf->alloc)
        {
          buf->alloc *= 2;
          buf->buf = xrealloc (buf->buf, buf->alloc);
        }
      cc = fread (buf->buf + buf->used, 1, buf->alloc - buf->used, fp);
      if (ferror (fp))
        {
          error (0, errno, _("read error"));
          cleanup ();
          exit (SORT_FAILURE);
        }
      buf->used += cc;
    }

  if (feof (fp) && buf->used && buf->buf[buf->used - 1] != eolchar)
    {
      if (buf->used == buf->alloc)
        {
          buf->alloc *= 2;
          buf->buf = xrealloc (buf->buf, buf->alloc);
        }
      buf->buf[buf->used++] = eolchar;
    }

  return buf->used;
}

/* Initialize LINES, allocating space for ALLOC lines initially.
   LIMIT is the maximum possible number of lines to allocate space
   for, ever.  */

static void
initlines (struct lines *lines, int alloc, int limit)
{
  lines->alloc = alloc;
  lines->lines = (struct line *) xmalloc (lines->alloc * sizeof (struct line));
  lines->used = 0;
  lines->limit = limit;
}

/* Return a pointer to the first character of the field specified
   by KEY in LINE. */

static char *
begfield (const struct line *line, const struct keyfield *key)
{
  register char *ptr = line->text, *lim = ptr + line->length;
  register int sword = key->sword, schar = key->schar;

  if (tab)
    while (ptr < lim && sword--)
      {
        while (ptr < lim && *ptr != tab)
          ++ptr;
        if (ptr < lim)
          ++ptr;
      }
  else
    while (ptr < lim && sword--)
      {
        while (ptr < lim && blanks[UCHAR (*ptr)])
          ++ptr;
        while (ptr < lim && !blanks[UCHAR (*ptr)])
          ++ptr;
      }

  if (key->skipsblanks)
    while (ptr < lim && blanks[UCHAR (*ptr)])
      ++ptr;

  if (ptr + schar <= lim)
    ptr += schar;
  else
    ptr = lim;

  return ptr;
}

/* Return the limit of (a pointer to the first character after) the field
   in LINE specified by KEY. */

static char *
limfield (const struct line *line, const struct keyfield *key)
{
  register char *ptr = line->text, *lim = ptr + line->length;
  register int eword = key->eword, echar = key->echar;

  /* Note: from the POSIX spec:
     The leading field separator itself is included in
     a field when -t is not used.  FIXME: move this comment up... */

  /* Move PTR past EWORD fields or to one past the last byte on LINE,
     whichever comes first.  If there are more than EWORD fields, leave
     PTR pointing at the beginning of the field having zero-based index,
     EWORD.  If a delimiter character was specified (via -t), then that
     `beginning' is the first character following the delimiting TAB.
     Otherwise, leave PTR pointing at the first `blank' character after
     the preceding field.  */
  if (tab)
    while (ptr < lim && eword--)
      {
        while (ptr < lim && *ptr != tab)
          ++ptr;
        if (ptr < lim && (eword || echar > 0))
          ++ptr;
      }
  else
    while (ptr < lim && eword--)
      {
        while (ptr < lim && blanks[UCHAR (*ptr)])
          ++ptr;
        while (ptr < lim && !blanks[UCHAR (*ptr)])
          ++ptr;
      }

#ifdef POSIX_UNSPECIFIED
  /* The following block of code makes GNU sort incompatible with
     standard Unix sort, so it's ifdef'd out for now.
     The POSIX spec isn't clear on how to interpret this.
     FIXME: request clarification.

     From: kwzh@gnu.ai.mit.edu (Karl Heuer)
     Date: Thu, 30 May 96 12:20:41 -0400

     [...]I believe I've found another bug in `sort'.

     $ cat /tmp/sort.in
     a b c 2 d
     pq rs 1 t
     $ textutils-1.15/src/sort +0.6 -0.7 </tmp/sort.in
     a b c 2 d
     pq rs 1 t
     $ /bin/sort +0.6 -0.7 </tmp/sort.in
     pq rs 1 t
     a b c 2 d

     Unix sort produced the answer I expected: sort on the single character
     in column 6.  GNU sort produced different results, because it disagrees
     on the interpretation of the key-end spec "-M.N".  Unix sort reads this
     as "skip M fields, then N characters"; but GNU sort wants it to mean
     "skip M fields, then either N characters or the rest of the current
     field, whichever comes first".  This extra clause applies only to
     key-ends, not key-starts.
     */

  /* Make LIM point to the end of (one byte past) the current field.  */
  if (tab)
    {
      char *newlim;
      newlim = memchr (ptr, tab, lim - ptr);
      if (newlim)
        lim = newlim;
    }
  else
    {
      char *newlim;
      newlim = ptr;
      while (newlim < lim && blanks[UCHAR (*newlim)])
        ++newlim;
      while (newlim < lim && !blanks[UCHAR (*newlim)])
        ++newlim;
      lim = newlim;
    }
#endif

  /* If we're skipping leading blanks, don't start counting characters
     until after skipping past any leading blanks.  */
  if (key->skipsblanks)
    while (ptr < lim && blanks[UCHAR (*ptr)])
      ++ptr;

  /* Advance PTR by ECHAR (if possible), but no further than LIM.  */
  if (ptr + echar <= lim)
    ptr += echar;
  else
    ptr = lim;

  return ptr;
}

/* FIXME */

void
trim_trailing_blanks (const char *a_start, char **a_end)
{
  while (*a_end > a_start && blanks[UCHAR (*(*a_end - 1))])
    --(*a_end);
}

/* Find the lines in BUF, storing pointers and lengths in LINES.
   Also replace newlines in BUF with NULs. */

static void
findlines (struct buffer *buf, struct lines *lines)
{
  register char *beg = buf->buf, *lim = buf->buf + buf->used, *ptr;
  struct keyfield *key = keyhead.next;

  lines->used = 0;

  while (beg < lim && (ptr = memchr (beg, eolchar, lim - beg))
         && lines->used < lines->limit)
    {
      /* There are various places in the code that rely on a NUL
         being at the end of in-core lines; NULs inside the lines
         will not cause trouble, though. */
      *ptr = '\0';

      if (lines->used == lines->alloc)
        {
          lines->alloc *= 2;
          lines->lines = (struct line *)
            xrealloc ((char *) lines->lines,
                      lines->alloc * sizeof (struct line));
        }

      lines->lines[lines->used].text = beg;
      lines->lines[lines->used].length = ptr - beg;

      /* Precompute the position of the first key for efficiency. */
      if (key)
        {
          if (key->eword >= 0)
            lines->lines[lines->used].keylim =
              limfield (&lines->lines[lines->used], key);
          else
            lines->lines[lines->used].keylim = ptr;

          if (key->sword >= 0)
            lines->lines[lines->used].keybeg =
              begfield (&lines->lines[lines->used], key);
          else
            {
              if (key->skipsblanks)
                while (blanks[UCHAR (*beg)])
                  ++beg;
              lines->lines[lines->used].keybeg = beg;
            }
          if (key->skipeblanks)
            {
              trim_trailing_blanks (lines->lines[lines->used].keybeg,
                                    &lines->lines[lines->used].keylim);
            }
        }
      else
        {
          lines->lines[lines->used].keybeg = 0;
          lines->lines[lines->used].keylim = 0;
        }

      ++lines->used;
      beg = ptr + 1;
    }

  buf->left = lim - beg;
}

/* Compare strings A and B containing decimal fractions < 1.  Each string
   should begin with a decimal point followed immediately by the digits
   of the fraction.  Strings not of this form are considered to be zero. */

/* The goal here, is to take two numbers a and b... compare these
   in parallel.  Instead of converting each, and then comparing the
   outcome.  Most likely stopping the comparison before the conversion
   is complete.  The algorithm used, in the old sort:

   Algorithm: fraccompare
   Action   : compare two decimal fractions
   accepts  : char *a, char *b
   returns  : -1 if a<b, 0 if a=b, 1 if a>b.
   implement:

   if *a == decimal_point AND *b == decimal_point
     find first character different in a and b.
     if both are digits, return the difference *a - *b.
     if *a is a digit
       skip past zeroes
       if digit return 1, else 0
     if *b is a digit
       skip past zeroes
       if digit return -1, else 0
   if *a is a decimal_point
     skip past decimal_point and zeroes
     if digit return 1, else 0
   if *b is a decimal_point
     skip past decimal_point and zeroes
     if digit return -1, else 0
   return 0

   The above implementation duplicates code, and thus there is room
   for improvement:
      the difference in code of a and b, is solved by using a
      reference to s, assigned to either a or b. and using diff
      to denote return value.
      the difference in either that start being a digit or
      the decimal point, is solved by testing if either is
      a decimal point, or if the other is a digit...

   if *a or *b is a decimal_point
      skip all chars where *a == *b
      if *a and *b are digits
        return *a - *b
      if *a is a digit or *a is a decimal_point
        s is a
        diff is 1
      else
        s is b
        diff is -1
      skip decimal_point in s
      skip zeroes in s
      if *s is a digit
        return diff
    return 0 */

#define USE_NEW_FRAC_COMPARE
#ifdef USE_NEW_FRAC_COMPARE

static int
fraccompare (register const char *a, register const char *b)
{
# ifdef ENABLE_NLS
  nls_fraction_found = 1;
# endif

  if (*a == decimal_point || *b == decimal_point)
    {
      register const char *s;
      int diff;

      while (*a == *b)
        {
          ++a;
          ++b;
          if (!ISDIGIT (*a))
            break;
        }

      if (ISDIGIT (*a) && ISDIGIT (*b))
        return (*a) - (*b);

      if (*a == decimal_point || (ISDIGIT (*a) && *b != decimal_point))
        {
          s = a;
          diff = 1;
        }
      else
        {
          s = b;
          diff = -1;
        }
      if (*s == decimal_point)
        ++s;
      while (*s == NUMERIC_ZERO)
        ++s;
      if (ISDIGIT (*s))
        return diff;
    }
  return 0;
}

#else
static int
fraccompare (register const char *a, register const char *b)
{
  register int tmpa = *a;
  register int tmpb = *b;

  if (tmpa == decimal_point && tmpb == decimal_point)
    {
      do
        tmpa = *++a, tmpb = *++b;
      while (tmpa == tmpb && ISDIGIT (tmpa));
      if (ISDIGIT (tmpa) && ISDIGIT (tmpb))
        return tmpa - tmpb;
      if (ISDIGIT (tmpa))
        {
          while (tmpa == NUMERIC_ZERO)
            tmpa = *++a;
          if (ISDIGIT (tmpa))
            return 1;
          return 0;
        }
      if (ISDIGIT (tmpb))
        {
          while (tmpb == NUMERIC_ZERO)
            tmpb = *++b;
          if (ISDIGIT (tmpb))
            return -1;
          return 0;
        }
      return 0;
    }
  else if (tmpa == decimal_point)
    {
      do
        tmpa = *++a;
      while (tmpa == NUMERIC_ZERO);
      if (ISDIGIT (tmpa))
        return 1;
      return 0;
    }
  else if (tmpb == decimal_point)
    {
      do
        tmpb = *++b;
      while (tmpb == NUMERIC_ZERO);
      if (ISDIGIT (tmpb))
        return -1;
      return 0;
    }
  return 0;
}
#endif

/* Compare strings A and B as numbers without explicitly converting them to
   machine numbers.  Comparatively slow for short strings, but asymptotically
   hideously fast. */

/* The code here, is like the above... continuous reoccurrance of the
   same code... improved 15-JAN-1997 in connection with native languages
   support */

#ifdef ENABLE_NLS

/* Decide the kind of fraction the program will use */
static void
nls_set_fraction (register unsigned char ch)
{
  if (!nls_fraction_found && ch != decimal_point)
    {
      if (ch == FLOATING_POINT)
        {                               /* US style */
          decimal_point = FLOATING_POINT;
          th_sep = FLOATING_COMMA;
        }
      else if (ch == FLOATING_COMMA)
        {                               /* EU style */
          decimal_point = FLOATING_COMMA;
          th_sep = FLOATING_POINT;
        }
      else if (ch != decimal_point)
        {                               /* Alien    */
          decimal_point = ch;
          th_sep = '\0';
        }
    }
  nls_fraction_found = 1;
}

/* Look for a fraction
   It isn't as simple as it looks... however, consider a number:
      1.234,00
      1,234.00
   It's easy to tell which is a decimal point, and which isn't.  We use
   the grouping information to find out how many digits are grouped together
   for thousand separator.

   The idea here, is to use the grouping information... but not to
   spend time with verifying the groups... not too much time, anyway.
   so, a number represented to us as:
      1.234.567,89
   will be taken and separated into different groups, separated by a
   separator character (Decimal point or thousands separator).
      {1,234,567}
   these are the groups of digits that lead to a separator character,
   and with the trailing group is added:
      {1,234,567,89}
   resulting in 4 groups of numbers.  If the resulting number of groups,
   are none, or just 1... this is not enough to decide anything about
   the decimal point.  We need at least two for that.  With two groups
   we have at least one separator.  That separator can be a decimal
   point, or a thousands separator... if it is a thousands separator
   the number of digits in the last group, will comply with the first
   rule in the grouping rule for numeric values. i.e.
      |{89}| = grouping[0]
   if so, and there are only two groups of numbers, the value cannot
   be determined.  If there are three or more numbers, the separator
   separating the groups is checked.  If these are the same, the
   character is determined to be a thousands separator.  If they are
   not the same, the last separator is determined to be a decimal
   point.  If checking the grouping rules, we find out that there
   are no grouping rules defined, either the grouping rules is NULL
   or the first grouping number is 0, then the locale format is used.

   We try to take an advantage of a special situation.  If the trailing
   group, the one that normally should be the fractional part, turns
   out to have the same length as the thousands separator rule says,
   making a doubt on that it may be a decimal point, we look for the
   group before that, i.e. with a two group form:
     {1234,567}
   where the grouping rule is 3;3... we take a look at group 1, and find
   out that |{1234}| > larger of the two first grouping rules, then
   the separator has to be a decimal point...
   */

static void
look_for_fraction (const char *s, const char *e)
{
  register const char *p;
  register unsigned short n = 0;
  static unsigned short max_groups = 0;
  static unsigned short *groups = NULL;

  if (groups == NULL)
    {
      max_groups = NLS_MAX_GROUPS;
      groups = (unsigned short *) xmalloc (sizeof (*groups) * max_groups);
    }

  /* skip blanks and signs */
  while (blanks[UCHAR (*s)] || *s == NEGATION_SIGN)
    s++;
  /* groups = {}, n = 0 */
  for (p = s; p < e; p++)
    {
      /* groups[n]={number of digits leading to separator n}
         n = number of separators so far */
      if (*p == decimal_point || *p == th_sep || *p == FLOATING_POINT)
        {
          if (++n >= max_groups)
            {
              /* BIG Number... enlarge table */
              max_groups += NLS_MAX_GROUPS;
              groups = (unsigned short *) xrealloc ((char *) groups,
                                                    (sizeof (*groups)
                                                     * max_groups));
            }
          groups[n] = (unsigned short) (p - s);
          s = p + 1;
        }
      else if (!ISDIGIT (*p))
        break;
      /* mem[s..p]=digits only */
    }
  /* n = number of separators in s..e */
  groups[++n] = (short) (p - s);
  /* n = groups in the number */
  if (n <= 1)
    return;                     /* Only one group of numbers... not enough */
  p = nls_grouping;
  /* p = address of group rules
     s = address of next character after separator */
  s = s - 1;                    /* s = address of last separator */
  if (p && *p)
    {
      /* a legal trailing group, iff groups[n] == first rule */
      if (groups[n] != (short) *p)
        nls_set_fraction (*s);
      else
        {
          if (n == 2)
            {                   /* Only two groups */
              if (groups[n - 1] > max (p[0], p[1]))
                nls_set_fraction (*s);
              return;
            }
          /* if the separators are the same, it's a thousands */
          if (*s != *(s - groups[n]))
            nls_set_fraction (*s);
          /* s[0] = thousands separator */
          else if (*s == th_sep)
            nls_fraction_found = 1;
        }
    }
  else
    {
      /* no grouping allowed here, last separator IS decimal point */
      nls_set_fraction (*s);
    }
}

static int
numcompare (register const char *a, register const char *b)
{
  int ret_code = 1;             /* normal return status, see later in code */
  int diff = 0;                 /* difference between two digits           */

  while (blanks[UCHAR (*a)])
    ++a;
  while (blanks[UCHAR (*b)])
    ++b;

  /* next character in a,b is non-blank */
  if ((*a == NEGATION_SIGN || *b == NEGATION_SIGN) && *a != *b)
    {
      /* a < 0, or b < 0, but not both */
      if (*a == NEGATION_SIGN)
        ret_code = -1, ++a;     /* a looks < b */
      else if (*b == NEGATION_SIGN)
        ret_code = 1, ++b;      /* b looks < a */
      /* bypass zeroes, decimal points, and thousand sep in a & b */
      while (*a == NUMERIC_ZERO || (th_sep && *a == th_sep)
             || *a == decimal_point)
        ++a;

      while (*b == NUMERIC_ZERO || (th_sep && *b == th_sep)
             || *b == decimal_point)
        ++b;

      if (ISDIGIT (*a) || ISDIGIT (*b))
        /* here, either a or b or both are digits
           if a and b are digits, the signed one is the lesser.
           if a is a digit, and not b.. it means b==0, and if b==0
           than either is signed if b is signed then -0 < a
           or if a is signed then -a < 0.  The ret_code is already set
           to mark that the signed number is the lesser, so we just
           return that number here.                                    */
        return ret_code;

      /* *a and *b are neither digits, they are equal -0 == +0 */
      return 0;
    }
  else
    {
      /* either both numbers are signed, or both are not-signed */
      if (*a == NEGATION_SIGN)
        {
          ++a;
          ++b;
          ret_code = -1;
        }
      /* if both are signed, then remember -100 < -10 (ret_code reversed!) */

      /* Skip any leading zeroes */
      while (*a == NUMERIC_ZERO)
        ++a;
      while (*b == NUMERIC_ZERO)
        ++b;

    continue_thousands:

      /* skip all equal digits */
      while (ISDIGIT (*a) && ISDIGIT (*b) && *a == *b)
        a++, b++;

      /* Here, we have either different digits, or possible fractions
         or thousand separators. */

      if (ISDIGIT (*a) && ISDIGIT (*b))
        {
          if (diff == 0)
            diff = ((*a) - (*b));       /* simple, isn't it? not quite */
          a++, b++;
          goto continue_thousands;
        }

      /* now, here either may be a fraction, or a thousand separator...
         or both.                                                        */
      /* We've decided what are decimal_points, and what are thousands sep */
      if ((th_sep != 0) && (*a == th_sep || *b == th_sep))
        {
          if (*a == th_sep)
            ++a;
          if (*b == th_sep)
            ++b;
          goto continue_thousands;      /* Ugly, but better than a while(1) */
        }

      if (ISDIGIT (*a))
        return ret_code;        /* a has more digits than b */
      if (ISDIGIT (*b))
        return ret_code * -1;   /* b has more digits than a */

      /* now, we should have the fractions solved */
      if ((diff == 0) && (*a == decimal_point || *b == decimal_point))
        return ret_code * fraccompare (a, b);

      return diff;              /* fall through here, and diff decides */
    }
}
#else
static int
numcompare (register const char *a, register const char *b)
{
  register int tmpa, tmpb, loga, logb, tmp;

  tmpa = UCHAR (*a);
  tmpb = UCHAR (*b);

  while (blanks[tmpa])
    tmpa = UCHAR (*++a);
  while (blanks[tmpb])
    tmpb = UCHAR (*++b);

  if (tmpa == NEGATION_SIGN)
    {
      do
        tmpa = UCHAR (*++a);
      while (tmpa == NUMERIC_ZERO);
      if (tmpb != NEGATION_SIGN)
        {
          if (tmpa == decimal_point)
            do
              tmpa = *++a;
            while (tmpa == NUMERIC_ZERO);
          if (ISDIGIT (tmpa))
            return -1;
          while (tmpb == NUMERIC_ZERO)
            tmpb = UCHAR (*++b);
          if (tmpb == decimal_point)
            do
              tmpb = *++b;
            while (tmpb == NUMERIC_ZERO);
          if (ISDIGIT (tmpb))
            return -1;
          return 0;
        }
      do
        tmpb = UCHAR (*++b);
      while (tmpb == NUMERIC_ZERO);

      while (tmpa == tmpb && ISDIGIT (tmpa))
        tmpa = UCHAR (*++a), tmpb = UCHAR (*++b);

      if ((tmpa == decimal_point && !ISDIGIT (tmpb))
          || (tmpb == decimal_point && !ISDIGIT (tmpa)))
        return -fraccompare (a, b);

      if (ISDIGIT (tmpa))
        for (loga = 1; ISDIGIT (UCHAR (*++a)); ++loga)
          ;
      else
        loga = 0;

      if (ISDIGIT (tmpb))
        for (logb = 1; ISDIGIT (UCHAR (*++b)); ++logb)
          ;
      else
        logb = 0;

      if ((tmp = logb - loga) != 0)
        return tmp;

      if (!loga)
        return 0;

      return tmpb - tmpa;
    }
  else if (tmpb == NEGATION_SIGN)
    {
      do
        tmpb = UCHAR (*++b);
      while (tmpb == NUMERIC_ZERO);
      if (tmpb == decimal_point)
        do
          tmpb = *++b;
        while (tmpb == NUMERIC_ZERO);
      if (ISDIGIT (tmpb))
        return 1;
      while (tmpa == NUMERIC_ZERO)
        tmpa = UCHAR (*++a);
      if (tmpa == decimal_point)
        do
          tmpa = UCHAR (*++a);
        while (tmpa == NUMERIC_ZERO);
      if (ISDIGIT (tmpa))
        return 1;
      return 0;
    }
  else
    {
      while (tmpa == NUMERIC_ZERO)
        tmpa = UCHAR (*++a);
      while (tmpb == NUMERIC_ZERO)
        tmpb = UCHAR (*++b);

      while (tmpa == tmpb && ISDIGIT (tmpa))
        tmpa = UCHAR (*++a), tmpb = UCHAR (*++b);

      if ((tmpa == decimal_point && !ISDIGIT (tmpb))
          || (tmpb == decimal_point && !ISDIGIT (tmpa)))
        return fraccompare (a, b);

      if (ISDIGIT (tmpa))
        for (loga = 1; ISDIGIT (UCHAR (*++a)); ++loga)
          ;
      else
        loga = 0;

      if (ISDIGIT (tmpb))
        for (logb = 1; ISDIGIT (UCHAR (*++b)); ++logb)
          ;
      else
        logb = 0;

      if ((tmp = loga - logb) != 0)
        return tmp;

      if (!loga)
        return 0;

      return tmpa - tmpb;
    }
}
#endif

static int
general_numcompare (const char *sa, const char *sb)
{
  double a, b;
  /* FIXME: add option to warn about failed conversions.  */
  /* FIXME: maybe add option to try expensive FP conversion
     only if A and B can't be compared more cheaply/accurately.  */
  if (xstrtod (sa, NULL, &a))
    {
      a = 0;
    }
  if (xstrtod (sb, NULL, &b))
    {
      b = 0;
    }
  return a == b ? 0 : a < b ? -1 : 1;
}

/* Return an integer in 1..12 of the month name S with length LEN.
   Return 0 if the name in S is not recognized.  */

static int
getmonth (const char *s, int len)
{
  char *month;
  register int i, lo = 0, hi = 12, result;

  while (len > 0 && blanks[UCHAR (*s)])
    {
      ++s;
      --len;
    }

  if (len == 0)
    return 0;

  month = (char *) alloca (len + 1);
  for (i = 0; i < len; ++i)
    month[i] = fold_toupper[UCHAR (s[i])];
  while (blanks[UCHAR (month[i - 1])])
    --i;
  month[i] = '\0';

  do
    {
      int ix = (lo + hi) / 2;

      len = strlen (monthtab[ix].name);
      if (NLS_STRNCMP (month, monthtab[ix].name, len) < 0)
        hi = ix;
      else
        lo = ix;
    }
  while (hi - lo > 1);

  result = (!strncmp (month, monthtab[lo].name, len) ? monthtab[lo].val : 0);

  return result;
}

#ifdef ENABLE_NLS
/* Look for the month in locale table, and if that fails try with
   us month name table                                              */
static int
nls_month_is_either_locale (const char *s, int len)
{
  int ind;

  monthtab = nls_monthtab;
  ind = getmonth (s, len);
  if (ind == 0)
    {
      monthtab = us_monthtab;
      ind = getmonth (s, len);
    }
  return ind;
}
#endif

/* Compare two lines A and B trying every key in sequence until there
   are no more keys or a difference is found. */

static int
keycompare (const struct line *a, const struct line *b)
{
  register char *texta, *textb, *lima, *limb;
  register unsigned char *translate;
  register int *ignore;
  struct keyfield *key;
  int diff = 0, iter = 0, lena, lenb;

  for (key = keyhead.next; key; key = key->next, ++iter)
    {
      int comparable_lengths = 1;

      ignore = key->ignore;
      translate = (unsigned char *) key->translate;

      /* Find the beginning and limit of each field. */
      if (iter || a->keybeg == NULL || b->keybeg == NULL)
        {
          if (key->eword >= 0)
            lima = limfield (a, key), limb = limfield (b, key);
          else
            lima = a->text + a->length, limb = b->text + b->length;

          if (key->sword >= 0)
            texta = begfield (a, key), textb = begfield (b, key);
          else
            {
              texta = a->text, textb = b->text;
              if (key->skipsblanks)
                {
                  while (texta < lima && blanks[UCHAR (*texta)])
                    ++texta;
                  while (textb < limb && blanks[UCHAR (*textb)])
                    ++textb;
                }
            }
        }
      else
        {
          /* For the first iteration only, the key positions have
             been precomputed for us. */
          texta = a->keybeg, lima = a->keylim;
          textb = b->keybeg, limb = b->keylim;
        }

      /* Find the lengths. */
      lena = lima - texta, lenb = limb - textb;
      if (lena < 0)
        lena = 0;
      if (lenb < 0)
        lenb = 0;

      if (key->skipeblanks)
        {
          char *a_end = texta + lena;
          char *b_end = textb + lenb;
          trim_trailing_blanks (texta, &a_end);
          trim_trailing_blanks (textb, &b_end);
          lena = a_end - texta;
          lenb = b_end - textb;
        }

      /* Actually compare the fields. */
      if (key->numeric)
        {
          if (*lima || *limb)
            {
              char savea = *lima, saveb = *limb;

              *lima = *limb = '\0';
              diff = numcompare (texta, textb);
              *lima = savea, *limb = saveb;
            }
          else
            diff = numcompare (texta, textb);

          if (diff)
            return key->reverse ? -diff : diff;
          continue;
        }
      else if (key->general_numeric)
        {
          if (*lima || *limb)
            {
              char savea = *lima, saveb = *limb;

              *lima = *limb = '\0';
              diff = general_numcompare (texta, textb);
              *lima = savea, *limb = saveb;
            }
          else
            diff = general_numcompare (texta, textb);

          if (diff)
            return key->reverse ? -diff : diff;
          continue;
        }
      else if (key->month)
        {
#ifdef ENABLE_NLS

          /* if we haven't decided which locale to go with, we get the
             month name from either.  If either month name is fully
             solved and the month name doesn't collide with the other
             locale... then use that table from there forward */
          if (!nls_month_found)
            {
              int x;

              x = nls_month_is_either_locale (texta, lena);
              nls_month_found = !nls_months_collide[x];
              if (nls_month_found)
                {
                  diff = x - getmonth (textb, lenb);
                }
              else
                {
                  diff = nls_month_is_either_locale (textb, lenb);
                  nls_month_found = !nls_months_collide[diff];
                  diff = x - diff;
                }
            }
          else
#endif
            diff = getmonth (texta, lena) - getmonth (textb, lenb);
          if (diff)
            return key->reverse ? -diff : diff;
          continue;
        }
#ifdef ENABLE_NLS

      /* Sorting like this may become slow, so in a simple locale the user
         can select a faster sort that is similar to ascii sort  */
      else if (need_locale)
        {
          /* FIXME: consider making parameters non-const, then when
             both ignore and translate are NULL (which should be most
             of the time) we could temporarily NUL-terminate them in
             place and avoid the copy.  */

          char *copy_a = (char *) alloca (lena + 1);
          char *copy_b = (char *) alloca (lenb + 1);
          int new_len_a, new_len_b, i;

          /* We can't use strcoll directly on the two strings,
             but rather must extract the text for the key
             (to NUL-terminate for strcoll) and handle any
             'ignore' and/or 'translate' before comparing.   */
          for (new_len_a = new_len_b = i = 0; i < max (lena, lenb); i++)
            {
              if (i < lena)
                {
                  copy_a[new_len_a] = (translate
                                       ? translate[UCHAR (texta[i])]
                                       : texta[i]);
                  if (!ignore || !ignore[UCHAR (texta[i])])
                    ++new_len_a;
                }
              if (i < lenb)
                {
                  copy_b[new_len_b] = (translate
                                       ? translate[UCHAR (textb[i])]
                                       : textb [i]);
                  if (!ignore || !ignore[UCHAR (textb[i])])
                    ++new_len_b;
                }
            }

          copy_a[new_len_a] = copy_b[new_len_b] = 0;

          diff = strcoll (copy_a, copy_b);

          /* Free copy_a and copy_b.  */
          alloca (0);

          if (diff)
            return key->reverse ? -diff : diff;

          continue;
        }
#endif
      else if (ignore && translate)

#define CMP_WITH_IGNORE(A, B)                                           \
  do                                                                    \
    {                                                                   \
          while (texta < lima && textb < limb)                          \
            {                                                           \
              while (texta < lima && ignore[UCHAR (*texta)])            \
                ++texta;                                                \
              while (textb < limb && ignore[UCHAR (*textb)])            \
                ++textb;                                                \
              if (texta < lima && textb < limb)                         \
                {                                                       \
                  if ((A) != (B))                                       \
                    {                                                   \
                      diff = UCHAR (A) - UCHAR (B);                     \
                      break;                                            \
                    }                                                   \
                  ++texta;                                              \
                  ++textb;                                              \
                }                                                       \
                                                                        \
              if (texta == lima && textb < limb && !ignore[UCHAR (*textb)]) \
                diff = -1;                                              \
              else if (texta < lima && textb == limb                    \
                       && !ignore[UCHAR (*texta)])                      \
                diff = 1;                                               \
            }                                                           \
                                                                        \
          if (diff == 0)                                                \
            {                                                           \
              while (texta < lima && ignore[UCHAR (*texta)])            \
                ++texta;                                                \
              while (textb < limb && ignore[UCHAR (*textb)])            \
                ++textb;                                                \
                                                                        \
              if (texta == lima && textb < limb)                        \
                diff = -1;                                              \
              else if (texta < lima && textb == limb)                   \
                diff = 1;                                               \
            }                                                           \
          /* Relative lengths are meaningless if characters were ignored.  \
             Handling this case here avoids what might be an invalid length  \
             comparison below.  */                                      \
          if (diff == 0 && texta == lima && textb == limb)              \
            comparable_lengths = 0;                                     \
    }                                                                   \
  while (0)

        CMP_WITH_IGNORE (translate[UCHAR (*texta)], translate[UCHAR (*textb)]);
      else if (ignore)
        CMP_WITH_IGNORE (UCHAR (*texta), UCHAR (*textb));
      else if (translate)
        while (texta < lima && textb < limb)
          {
            if (translate[UCHAR (*texta++)] != translate[UCHAR (*textb++)])
              {
                diff = (UCHAR (translate[UCHAR (*--texta)])
                        - UCHAR (translate[UCHAR (*--textb)]));
                break;
              }
          }
      else
        {
          diff = NLS_MEMCMP (texta, textb, min (lena, lenb));
        }

      if (diff)
        return key->reverse ? -diff : diff;
      if (comparable_lengths && (diff = lena - lenb) != 0)
        return key->reverse ? -diff : diff;
    }

  return 0;
}

/* Compare two lines A and B, returning negative, zero, or positive
   depending on whether A compares less than, equal to, or greater than B. */

static int
compare (register const struct line *a, register const struct line *b)
{
  int diff, tmpa, tmpb, mini;

  /* First try to compare on the specified keys (if any).
     The only two cases with no key at all are unadorned sort,
     and unadorned sort -r. */
  if (keyhead.next)
    {
      diff = keycompare (a, b);
      if (diff != 0)
        return diff;
      if (unique || stable)
        return 0;
    }

  /* If the keys all compare equal (or no keys were specified)
     fall through to the default byte-by-byte comparison. */
  tmpa = a->length, tmpb = b->length;
  mini = min (tmpa, tmpb);
  if (mini == 0)
    diff = tmpa - tmpb;
  else
    {
      char *ap = a->text, *bp = b->text;

#ifdef ENABLE_NLS
      if (need_locale)  /* want absolutely correct sorting */
        {
          diff = strcoll (ap, bp);
          return reverse ? -diff : diff;
        }
#endif
      diff = UCHAR (*ap) - UCHAR (*bp);
      if (diff == 0)
        {
          diff = NLS_MEMCMP (ap, bp, mini);
          if (diff == 0)
            diff = tmpa - tmpb;
        }
    }

  return reverse ? -diff : diff;
}

/* Check that the lines read from the given FP come in order.  Print a
   diagnostic (FILE_NAME, line number, contents of line) to stderr and return
   the line number of the first out-of-order line (counting from 1) if they
   are not in order.  Otherwise, print no diagnostic and return zero.  */

static int
checkfp (FILE *fp, const char *file_name)
{
  struct buffer buf;            /* Input buffer. */
  struct lines lines;           /* Lines scanned from the buffer. */
  struct line temp;             /* Copy of previous line. */
  int cc;                       /* Character count. */
  int alloc;
  int line_number = 1;
  struct line *disorder_line;
  int disorder_line_number = 0;

#ifdef lint  /* Suppress `used before initialized' warning.  */
  disorder_line = NULL;
#endif

  initbuf (&buf, mergealloc);
  initlines (&lines, mergealloc / linelength + 1,
             LINEALLOC / ((NMERGE + NMERGE) * sizeof (struct line)));
  alloc = linelength;
  temp.text = xmalloc (alloc);

  cc = fillbuf (&buf, fp);
  if (cc == 0)
    goto finish;

  findlines (&buf, &lines);

  while (1)
    {
      struct line *prev_line;   /* Pointer to previous line. */
      int cmp;                  /* Result of calling compare. */
      int i;

      /* Compare each line in the buffer with its successor. */
      for (i = 0; i < lines.used - 1; ++i)
        {
          cmp = compare (&lines.lines[i], &lines.lines[i + 1]);
          if ((unique && cmp >= 0) || (cmp > 0))
            {
              disorder_line = &lines.lines[i + 1];
              disorder_line_number = line_number + i + 1;
              goto finish;
            }
        }

      line_number += lines.used;

      /* Save the last line of the buffer and refill the buffer. */
      prev_line = lines.lines + (lines.used - 1);
      if (prev_line->length + 1 > alloc)
        {
          do
            {
              alloc *= 2;
            }
          while (alloc < prev_line->length + 1);
          temp.text = xrealloc (temp.text, alloc);
        }
      assert (prev_line->length + 1 <= alloc);
      memcpy (temp.text, prev_line->text, prev_line->length + 1);
      temp.length = prev_line->length;
      temp.keybeg = temp.text + (prev_line->keybeg - prev_line->text);
      temp.keylim = temp.text + (prev_line->keylim - prev_line->text);

      cc = fillbuf (&buf, fp);
      if (cc == 0)
        break;

      findlines (&buf, &lines);
      /* Make sure the line saved from the old buffer contents is
         less than or equal to the first line of the new buffer. */
      cmp = compare (&temp, &lines.lines[0]);
      if ((unique && cmp >= 0) || (cmp > 0))
        {
          disorder_line = &lines.lines[0];
          disorder_line_number = line_number;
          break;
        }
    }

finish:
  xfclose (fp);

  if (disorder_line_number)
    {
      fprintf (stderr, _("%s: %s:%d: disorder: "), program_name, file_name,
               disorder_line_number);
      write_bytes (disorder_line->text, disorder_line->length, stderr);
      putc (eolchar, stderr);
    }

  free (buf.buf);
  free ((char *) lines.lines);
  free (temp.text);
  return disorder_line_number;
}

/* Merge lines from FPS onto OFP.  NFPS cannot be greater than NMERGE.
   Close FPS before returning. */

static void
mergefps (FILE **fps, register int nfps, FILE *ofp)
{
  struct buffer buffer[NMERGE]; /* Input buffers for each file. */
  struct lines lines[NMERGE];   /* Line tables for each buffer. */
  struct line saved;            /* Saved line for unique check. */
  int savedflag = 0;            /* True if there is a saved line. */
  int savealloc;                /* Size allocated for the saved line. */
  int cur[NMERGE];              /* Current line in each line table. */
  int ord[NMERGE];              /* Table representing a permutation of fps,
                                   such that lines[ord[0]].lines[cur[ord[0]]]
                                   is the smallest line and will be next
                                   output. */
  register int i, j, t;

#ifdef lint  /* Suppress `used before initialized' warning.  */
  savealloc = 0;
#endif

  /* Allocate space for a saved line if necessary. */
  if (unique)
    {
      savealloc = linelength;
      saved.text = xmalloc (savealloc);
    }

  /* Read initial lines from each input file. */
  for (i = 0; i < nfps; ++i)
    {
      initbuf (&buffer[i], mergealloc);
      /* If a file is empty, eliminate it from future consideration. */
      while (i < nfps && !fillbuf (&buffer[i], fps[i]))
        {
          xfclose (fps[i]);
          --nfps;
          for (j = i; j < nfps; ++j)
            fps[j] = fps[j + 1];
        }
      if (i == nfps)
        free (buffer[i].buf);
      else
        {
          initlines (&lines[i], mergealloc / linelength + 1,
                     LINEALLOC / ((NMERGE + NMERGE) * sizeof (struct line)));
          findlines (&buffer[i], &lines[i]);
          cur[i] = 0;
        }
    }

  /* Set up the ord table according to comparisons among input lines.
     Since this only reorders two items if one is strictly greater than
     the other, it is stable. */
  for (i = 0; i < nfps; ++i)
    ord[i] = i;
  for (i = 1; i < nfps; ++i)
    if (compare (&lines[ord[i - 1]].lines[cur[ord[i - 1]]],
                 &lines[ord[i]].lines[cur[ord[i]]]) > 0)
      t = ord[i - 1], ord[i - 1] = ord[i], ord[i] = t, i = 0;

  /* Repeatedly output the smallest line until no input remains. */
  while (nfps)
    {
      /* If uniqified output is turned on, output only the first of
         an identical series of lines. */
      if (unique)
        {
          if (savedflag && compare (&saved, &lines[ord[0]].lines[cur[ord[0]]]))
            {
              write_bytes (saved.text, saved.length, ofp);
              putc (eolchar, ofp);
              savedflag = 0;
            }
          if (!savedflag)
            {
              if (savealloc < lines[ord[0]].lines[cur[ord[0]]].length + 1)
                {
                  while (savealloc < lines[ord[0]].lines[cur[ord[0]]].length + 1)
                    savealloc *= 2;
                  saved.text = xrealloc (saved.text, savealloc);
                }
              saved.length = lines[ord[0]].lines[cur[ord[0]]].length;
              memcpy (saved.text, lines[ord[0]].lines[cur[ord[0]]].text,
                      saved.length + 1);
              if (lines[ord[0]].lines[cur[ord[0]]].keybeg != NULL)
                {
                  saved.keybeg = saved.text +
                    (lines[ord[0]].lines[cur[ord[0]]].keybeg
                     - lines[ord[0]].lines[cur[ord[0]]].text);
                }
              if (lines[ord[0]].lines[cur[ord[0]]].keylim != NULL)
                {
                  saved.keylim = saved.text +
                    (lines[ord[0]].lines[cur[ord[0]]].keylim
                     - lines[ord[0]].lines[cur[ord[0]]].text);
                }
              savedflag = 1;
            }
        }
      else
        {
          write_bytes (lines[ord[0]].lines[cur[ord[0]]].text,
                       lines[ord[0]].lines[cur[ord[0]]].length, ofp);
          putc (eolchar, ofp);
        }

      /* Check if we need to read more lines into core. */
      if (++cur[ord[0]] == lines[ord[0]].used)
        {
          if (fillbuf (&buffer[ord[0]], fps[ord[0]]))
            {
              findlines (&buffer[ord[0]], &lines[ord[0]]);
              cur[ord[0]] = 0;
            }
          else
            {
              /* We reached EOF on fps[ord[0]]. */
              for (i = 1; i < nfps; ++i)
                if (ord[i] > ord[0])
                  --ord[i];
              --nfps;
              xfclose (fps[ord[0]]);
              free (buffer[ord[0]].buf);
              free ((char *) lines[ord[0]].lines);
              for (i = ord[0]; i < nfps; ++i)
                {
                  fps[i] = fps[i + 1];
                  buffer[i] = buffer[i + 1];
                  lines[i] = lines[i + 1];
                  cur[i] = cur[i + 1];
                }
              for (i = 0; i < nfps; ++i)
                ord[i] = ord[i + 1];
              continue;
            }
        }

      /* The new line just read in may be larger than other lines
         already in core; push it back in the queue until we encounter
         a line larger than it. */
      for (i = 1; i < nfps; ++i)
        {
          t = compare (&lines[ord[0]].lines[cur[ord[0]]],
                       &lines[ord[i]].lines[cur[ord[i]]]);
          if (!t)
            t = ord[0] - ord[i];
          if (t < 0)
            break;
        }
      t = ord[0];
      for (j = 1; j < i; ++j)
        ord[j - 1] = ord[j];
      ord[i - 1] = t;
    }

  if (unique && savedflag)
    {
      write_bytes (saved.text, saved.length, ofp);
      putc (eolchar, ofp);
      free (saved.text);
    }
}

#ifdef ENABLE_NLS

/* Find the numeric format that this file represents to us for sorting. */
static void
nls_numeric_format (const struct line *line, int nlines)
{
  struct nls_keyfield *n_key = nls_keyhead;

  /* line = first line, nlines = number of lines,
     nls_fraction_found = false                           */
  for (; !nls_fraction_found && nlines > 0; line++, nlines--)
    {
      int iter;
      for (iter = 0; !nls_fraction_found; iter++)
        {
          char *text;
          char *lim;
          struct keyfield *key = n_key->key;

          /* text = {}, lim = {}, key = first key */
          if (iter || line->keybeg == NULL)
            {
              /* Succeding keys, where the key field is
                 specified                              */
              if (key->eword >= 0) /* key->eword = length of key */
                lim = limfield (line, key);
              else
                lim = line->text + line->length;
              /* lim = end of key field */

              if (key->sword >= 0) /* key->sword = start of key */
                text = begfield (line, key);
              else
                text = line->text;
              /* text = start of field */
            }
          else
            {
              /* First key is always the whole line */
              text = line->keybeg;
              lim = line->keylim;
            }
          /* text = start of text to sort
             lim  = end of text to sort    */

          look_for_fraction (text, lim);

          /* nls_fraction_found = decimal_point found? */

          if ((n_key = n_key->next) == nls_keyhead)
            break;  /* No more keys for this line */
        }
    }
  nls_fraction_found = 1;
  /* decide on current decimal_point known */
}

#endif

/* Sort the array LINES with NLINES members, using TEMP for temporary space. */

static void
sortlines (struct line *lines, int nlines, struct line *temp)
{
  register struct line *lo, *hi, *t;
  register int nlo, nhi;

  if (nlines == 2)
    {
      if (compare (&lines[0], &lines[1]) > 0)
        {
          *temp = lines[0];
          lines[0] = lines[1];
          lines[1] = *temp;
        }
      return;
    }

  nlo = nlines / 2;
  lo = lines;
  nhi = nlines - nlo;
  hi = lines + nlo;

  if (nlo > 1)
    sortlines (lo, nlo, temp);

  if (nhi > 1)
    sortlines (hi, nhi, temp);

  t = temp;

  while (nlo && nhi)
    if (compare (lo, hi) <= 0)
      *t++ = *lo++, --nlo;
    else
      *t++ = *hi++, --nhi;
  while (nlo--)
    *t++ = *lo++;

  for (lo = lines, nlo = nlines - nhi, t = temp; nlo; --nlo)
    *lo++ = *t++;
}

/* Check that each of the NFILES FILES is ordered.
   Return a count of disordered files. */

static int
check (char **files, int nfiles)
{
  int i, disorders = 0;
  FILE *fp;

  for (i = 0; i < nfiles; ++i)
    {
      fp = xfopen (files[i], "r");
      if (checkfp (fp, files[i]))
        {
          ++disorders;
        }
    }
  return disorders;
}

/* Merge NFILES FILES onto OFP. */

static void
merge (char **files, int nfiles, FILE *ofp)
{
  int i, j, t;
  char *temp;
  FILE *fps[NMERGE], *tfp;

  while (nfiles > NMERGE)
    {
      t = 0;
      for (i = 0; i < nfiles / NMERGE; ++i)
        {
          for (j = 0; j < NMERGE; ++j)
            fps[j] = xfopen (files[i * NMERGE + j], "r");
          tfp = xtmpfopen (temp = tempname ());
          mergefps (fps, NMERGE, tfp);
          xfclose (tfp);
          for (j = 0; j < NMERGE; ++j)
            zaptemp (files[i * NMERGE + j]);
          files[t++] = temp;
        }
      for (j = 0; j < nfiles % NMERGE; ++j)
        fps[j] = xfopen (files[i * NMERGE + j], "r");
      tfp = xtmpfopen (temp = tempname ());
      mergefps (fps, nfiles % NMERGE, tfp);
      xfclose (tfp);
      for (j = 0; j < nfiles % NMERGE; ++j)
        zaptemp (files[i * NMERGE + j]);
      files[t++] = temp;
      nfiles = t;
    }

  for (i = 0; i < nfiles; ++i)
    fps[i] = xfopen (files[i], "r");
  mergefps (fps, i, ofp);
  for (i = 0; i < nfiles; ++i)
    zaptemp (files[i]);
}

/* Sort NFILES FILES onto OFP. */

static void
sort (char **files, int nfiles, FILE *ofp)
{
  struct buffer buf;
  struct lines lines;
  struct line *tmp;
  int i, ntmp;
  FILE *fp, *tfp;
  struct tempnode *node;
  int n_temp_files = 0;
  char **tempfiles;

  initbuf (&buf, sortalloc);
  initlines (&lines, sortalloc / linelength + 1,
             LINEALLOC / sizeof (struct line));
  ntmp = lines.alloc;
  tmp = (struct line *) xmalloc (ntmp * sizeof (struct line));

  while (nfiles--)
    {
      fp = xfopen (*files++, "r");
      while (fillbuf (&buf, fp))
        {
          findlines (&buf, &lines);
          if (lines.used > ntmp)
            {
              while (lines.used > ntmp)
                ntmp *= 2;
              tmp = (struct line *)
                xrealloc ((char *) tmp, ntmp * sizeof (struct line));
            }
#ifdef ENABLE_NLS
          if (nls_keyhead)
            nls_keyhead = nls_keyhead->next;
          if (!nls_fraction_found && nls_keyhead)
            nls_numeric_format (lines.lines, lines.used);
#endif
          sortlines (lines.lines, lines.used, tmp);
          if (feof (fp) && !nfiles && !n_temp_files && !buf.left)
            {
              tfp = ofp;
            }
          else
            {
              ++n_temp_files;
              tfp = xtmpfopen (tempname ());
            }
          for (i = 0; i < lines.used; ++i)
            if (!unique || i == 0
                || compare (&lines.lines[i], &lines.lines[i - 1]))
              {
                write_bytes (lines.lines[i].text, lines.lines[i].length, tfp);
                putc (eolchar, tfp);
              }
          if (tfp != ofp)
            xfclose (tfp);
        }
      xfclose (fp);
    }

  free (buf.buf);
  free ((char *) lines.lines);
  free ((char *) tmp);

  if (n_temp_files)
    {
      tempfiles = (char **) xmalloc (n_temp_files * sizeof (char *));
      i = n_temp_files;
      for (node = temphead.next; i > 0; node = node->next)
        tempfiles[--i] = node->name;
      merge (tempfiles, n_temp_files, ofp);
      free ((char *) tempfiles);
    }
}

/* Insert key KEY at the end of the list (`keyhead'). */

static void
insertkey (struct keyfield *key)
{
  struct keyfield *k = &keyhead;

  while (k->next)
    k = k->next;
  k->next = key;
  key->next = NULL;
#ifdef ENABLE_NLS
  if (key->numeric || key->general_numeric)
    {
      struct nls_keyfield *nk;

      nk = (struct nls_keyfield *) xmalloc (sizeof (struct nls_keyfield));
      nk->key = key;
      if (nls_keyhead)
        {
          nk->next = nls_keyhead->next;
          nls_keyhead->next = nk;
        }
      else
        nk->next = nk;
      nls_keyhead = nk;
    }
#endif
}

static void
badfieldspec (const char *s)
{
  error (SORT_FAILURE, 0, _("invalid field specification `%s'"), s);
}

/* Handle interrupts and hangups. */

static void
sighandler (int sig)
{
#ifdef SA_INTERRUPT
  struct sigaction sigact;

  sigact.sa_handler = SIG_DFL;
  sigemptyset (&sigact.sa_mask);
  sigact.sa_flags = 0;
  sigaction (sig, &sigact, NULL);
#else                           /* !SA_INTERRUPT */
  signal (sig, SIG_DFL);
#endif                          /* SA_INTERRUPT */
  cleanup ();
  kill (getpid (), sig);
}

/* Set the ordering options for KEY specified in S.
   Return the address of the first character in S that
   is not a valid ordering option.
   BLANKTYPE is the kind of blanks that 'b' should skip. */

static char *
set_ordering (register const char *s, struct keyfield *key,
              enum blanktype blanktype)
{
  while (*s)
    {
      switch (*s)
        {
        case 'b':
          if (blanktype == bl_start || blanktype == bl_both)
            key->skipsblanks = 1;
          if (blanktype == bl_end || blanktype == bl_both)
            key->skipeblanks = 1;
          break;
        case 'd':
          key->ignore = nondictionary;
          break;
        case 'f':
          key->translate = fold_toupper;
          break;
        case 'g':
          key->general_numeric = 1;
          break;
        case 'i':
          key->ignore = nonprinting;
          break;
        case 'M':
          key->month = 1;
          break;
        case 'n':
          key->numeric = 1;
          break;
        case 'r':
          key->reverse = 1;
          break;
        default:
          return (char *) s;
        }
      ++s;
    }
  return (char *) s;
}

static void
key_init (struct keyfield *key)
{
  memset (key, 0, sizeof (*key));
  key->eword = -1;
}

/* strdup and return the result of setlocale, but guard against a NULL
   return value.  If setlocale returns NULL, strdup FAIL_VAL instead.  */

#if defined ENABLE_NLS && ( !defined __GLIBC__ || __GLIBC__ < 2 )
static inline char *
my_setlocale (const char *locale, const char *fail_val)
{
  char *s = setlocale (LC_ALL, locale);
  if (s == NULL)
    s = (char *) fail_val;
  return xstrdup (s);
}
#endif

int
main (int argc, char **argv)
{
  struct keyfield *key = NULL, gkey;
  char *s;
  int i, t, t2;
  int checkonly = 0, mergeonly = 0, nfiles = 0;
  char *minus = "-", *outfile = minus, **files, *tmp;
  FILE *ofp;
#ifdef SA_INTERRUPT
  struct sigaction oldact, newact;
#endif                          /* SA_INTERRUPT */

  program_name = argv[0];

#ifdef ENABLE_NLS

  /* Determine whether the current locale is C or POSIX.  */
# if defined __GLIBC__ && __GLIBC__ >= 2
  s = setlocale (LC_ALL, "");
  if (s != NULL && !STREQ (s, "C") && !STREQ (s, "POSIX"))
    /* The current locale is neither C nor POSIX.  We'll need to do
       more work.  */
    need_locale = 1;
# else
  {
    char *c_locale_string = my_setlocale ("C", "");
    char *posix_locale_string = my_setlocale ("POSIX", "");
    char *current_locale_string = setlocale (LC_ALL, "");

    if (current_locale_string != NULL
        && !STREQ (current_locale_string, c_locale_string)
        && !STREQ (current_locale_string, posix_locale_string))
        /* The current locale is neither C nor POSIX.
           We'll need to do more work.  */
        need_locale = 1;

    free (c_locale_string);
    free (posix_locale_string);
  }
# endif

  /* Let's get locale's representation of the decimal point */
  {
    struct lconv *lconvp = localeconv ();

    decimal_point = *lconvp->decimal_point;
    th_sep        = *lconvp->thousands_sep;
    nls_grouping  =  (char *) (lconvp->grouping);
  }

  /* if locale doesn't define a decimal point, we'll use the
     US notation.                                            */
  if (decimal_point == '\0')
    decimal_point = FLOATING_POINT;
  else
    nls_fraction_found = 0;  /* Figure out which decimal point to use  */

  nls_month_found = 0;  /* Figure out which month notation to use */

  monthtab = nls_monthtab;

#endif /* NLS */

  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
                      AUTHORS, usage);

  have_read_stdin = 0;
  inittables ();

  temp_dir = getenv ("TMPDIR");
  if (temp_dir == NULL)
    temp_dir = DEFAULT_TMPDIR;

  /* Change the way xmalloc and xrealloc fail.  */
  xalloc_exit_failure = SORT_FAILURE;
  xalloc_fail_func = cleanup;

#ifdef SA_INTERRUPT
  newact.sa_handler = sighandler;
  sigemptyset (&newact.sa_mask);
  newact.sa_flags = 0;

  sigaction (SIGINT, NULL, &oldact);
  if (oldact.sa_handler != SIG_IGN)
    sigaction (SIGINT, &newact, NULL);
  sigaction (SIGHUP, NULL, &oldact);
  if (oldact.sa_handler != SIG_IGN)
    sigaction (SIGHUP, &newact, NULL);
  sigaction (SIGPIPE, NULL, &oldact);
  if (oldact.sa_handler != SIG_IGN)
    sigaction (SIGPIPE, &newact, NULL);
  sigaction (SIGTERM, NULL, &oldact);
  if (oldact.sa_handler != SIG_IGN)
    sigaction (SIGTERM, &newact, NULL);
#else                           /* !SA_INTERRUPT */
  if (signal (SIGINT, SIG_IGN) != SIG_IGN)
    signal (SIGINT, sighandler);
  if (signal (SIGHUP, SIG_IGN) != SIG_IGN)
    signal (SIGHUP, sighandler);
  if (signal (SIGPIPE, SIG_IGN) != SIG_IGN)
    signal (SIGPIPE, sighandler);
  if (signal (SIGTERM, SIG_IGN) != SIG_IGN)
    signal (SIGTERM, sighandler);
#endif                          /* !SA_INTERRUPT */

  gkey.sword = gkey.eword = -1;
  gkey.ignore = NULL;
  gkey.translate = NULL;
  gkey.numeric = gkey.general_numeric = gkey.month = gkey.reverse = 0;
  gkey.skipsblanks = gkey.skipeblanks = 0;

  files = (char **) xmalloc (sizeof (char *) * argc);

  for (i = 1; i < argc; ++i)
    {
      if (argv[i][0] == '+')
        {
          if (key)
            insertkey (key);
          key = (struct keyfield *) xmalloc (sizeof (struct keyfield));
          key_init (key);
          s = argv[i] + 1;
          if (! (ISDIGIT (*s) || (*s == '.' && ISDIGIT (s[1]))))
            badfieldspec (argv[i]);
          for (t = 0; ISDIGIT (*s); ++s)
            t = 10 * t + *s - '0';
          t2 = 0;
          if (*s == '.')
            for (++s; ISDIGIT (*s); ++s)
              t2 = 10 * t2 + *s - '0';
          if (t2 || t)
            {
              key->sword = t;
              key->schar = t2;
            }
          else
            key->sword = -1;
          s = set_ordering (s, key, bl_start);
          if (*s)
            badfieldspec (argv[i]);
        }
      else if (argv[i][0] == '-' && argv[i][1])
        {
          s = argv[i] + 1;
          if (ISDIGIT (*s) || (*s == '.' && ISDIGIT (s[1])))
            {
              if (!key)
                {
                  /* Provoke with `sort -9'.  */
                  error (0, 0, _("when using the old-style +POS and -POS \
key specifiers,\nthe +POS specifier must come first"));
                  usage (SORT_FAILURE);
                }
              for (t = 0; ISDIGIT (*s); ++s)
                t = t * 10 + *s - '0';
              t2 = 0;
              if (*s == '.')
                for (++s; ISDIGIT (*s); ++s)
                  t2 = t2 * 10 + *s - '0';
              key->eword = t;
              key->echar = t2;
              s = set_ordering (s, key, bl_end);
              if (*s)
                badfieldspec (argv[i]);
              insertkey (key);
              key = NULL;
            }
          else
            while (*s)
              {
                s = set_ordering (s, &gkey, bl_both);
                switch (*s)
                  {
                  case '\0':
                    break;
                  case 'c':
                    checkonly = 1;
                    break;
                  case 'k':
                    if (s[1])
                      ++s;
                    else
                      {
                        if (i == argc - 1)
                          error (SORT_FAILURE, 0,
                                 _("option `-k' requires an argument"));
                        else
                          s = argv[++i];
                      }
                    if (key)
                      insertkey (key);
                    key = (struct keyfield *)
                      xmalloc (sizeof (struct keyfield));
                    key_init (key);
                    /* Get POS1. */
                    if (!ISDIGIT (*s))
                      badfieldspec (argv[i]);
                    for (t = 0; ISDIGIT (*s); ++s)
                      t = 10 * t + *s - '0';
                    if (t == 0)
                      {
                        /* Provoke with `sort -k0' */
                        error (0, 0, _("the starting field number argument \
to the `-k' option must be positive"));
                        badfieldspec (argv[i]);
                      }
                    --t;
                    t2 = 0;
                    if (*s == '.')
                      {
                        if (!ISDIGIT (s[1]))
                          {
                            /* Provoke with `sort -k1.' */
                            error (0, 0, _("starting field spec has `.' but \
lacks following character offset"));
                            badfieldspec (argv[i]);
                          }
                        for (++s; ISDIGIT (*s); ++s)
                          t2 = 10 * t2 + *s - '0';
                        if (t2 == 0)
                          {
                            /* Provoke with `sort -k1.0' */
                            error (0, 0, _("starting field character offset \
argument to the `-k' option\nmust be positive"));
                            badfieldspec (argv[i]);
                          }
                        --t2;
                      }
                    if (t2 || t)
                      {
                        key->sword = t;
                        key->schar = t2;
                      }
                    else
                      key->sword = -1;
                    s = set_ordering (s, key, bl_start);
                    if (*s == 0)
                      {
                        key->eword = -1;
                        key->echar = 0;
                      }
                    else if (*s != ',')
                      badfieldspec (argv[i]);
                    else if (*s == ',')
                      {
                        /* Skip over comma.  */
                        ++s;
                        if (*s == 0)
                          {
                            /* Provoke with `sort -k1,' */
                            error (0, 0, _("field specification has `,' but \
lacks following field spec"));
                            badfieldspec (argv[i]);
                          }
                        /* Get POS2. */
                        for (t = 0; ISDIGIT (*s); ++s)
                          t = t * 10 + *s - '0';
                        if (t == 0)
                          {
                            /* Provoke with `sort -k1,0' */
                            error (0, 0, _("ending field number argument \
to the `-k' option must be positive"));
                            badfieldspec (argv[i]);
                          }
                        --t;
                        t2 = 0;
                        if (*s == '.')
                          {
                            if (!ISDIGIT (s[1]))
                              {
                                /* Provoke with `sort -k1,1.' */
                                error (0, 0, _("ending field spec has `.' \
but lacks following character offset"));
                                badfieldspec (argv[i]);
                              }
                            for (++s; ISDIGIT (*s); ++s)
                              t2 = t2 * 10 + *s - '0';
                          }
                        else
                          {
                            /* `-k 2,3' is equivalent to `+1 -3'.  */
                            ++t;
                          }
                        key->eword = t;
                        key->echar = t2;
                        s = set_ordering (s, key, bl_end);
                        if (*s)
                          badfieldspec (argv[i]);
                      }
                    insertkey (key);
                    key = NULL;
                    goto outer;
                  case 'm':
                    mergeonly = 1;
                    break;
                  case 'o':
                    if (s[1])
                      outfile = s + 1;
                    else
                      {
                        if (i == argc - 1)
                          error (SORT_FAILURE, 0,
                                 _("option `-o' requires an argument"));
                        else
                          outfile = argv[++i];
                      }
                    goto outer;
                  case 's':
                    stable = 1;
                    break;
                  case 't':
                    if (s[1])
                      tab = *++s;
                    else if (i < argc - 1)
                      {
                        tab = *argv[++i];
                        goto outer;
                      }
                    else
                      error (SORT_FAILURE, 0,
                             _("option `-t' requires an argument"));
                    break;
                  case 'T':
                    if (s[1])
                      temp_dir = ++s;
                    else
                      {
                        if (i < argc - 1)
                          temp_dir = argv[++i];
                        else
                          error (SORT_FAILURE, 0,
                                 _("option `-T' requires an argument"));
                      }
                    goto outer;
                    /* break; */
                  case 'u':
                    unique = 1;
                    break;
                  case 'z':
                    eolchar = 0;
                    break;
                  case 'y':
                    /* Accept and ignore e.g. -y0 for compatibility with
                       Solaris 2.  */
                    goto outer;
                  default:
                    fprintf (stderr, _("%s: unrecognized option `-%c'\n"),
                             argv[0], *s);
                    usage (SORT_FAILURE);
                  }
                if (*s)
                  ++s;
              }
        }
      else                      /* Not an option. */
        {
          files[nfiles++] = argv[i];
        }
    outer:;
    }

  if (key)
    insertkey (key);

  /* Inheritance of global options to individual keys. */
  for (key = keyhead.next; key; key = key->next)
    if (!key->ignore && !key->translate && !key->skipsblanks && !key->reverse
        && !key->skipeblanks && !key->month && !key->numeric
        && !key->general_numeric)
      {
        key->ignore = gkey.ignore;
        key->translate = gkey.translate;
        key->skipsblanks = gkey.skipsblanks;
        key->skipeblanks = gkey.skipeblanks;
        key->month = gkey.month;
        key->numeric = gkey.numeric;
        key->general_numeric = gkey.general_numeric;
        key->reverse = gkey.reverse;
      }

  if (!keyhead.next && (gkey.ignore || gkey.translate || gkey.skipsblanks
                        || gkey.skipeblanks || gkey.month || gkey.numeric
                        || gkey.general_numeric))
    insertkey (&gkey);
  reverse = gkey.reverse;

  if (nfiles == 0)
    {
      nfiles = 1;
      files = &minus;
    }

  if (checkonly)
    {
      /* POSIX requires that sort return 1 IFF invoked with -c and the
         input is not properly sorted.  */
      exit (check (files, nfiles) == 0 ? 0 : 1);
    }

  if (!STREQ (outfile, "-"))
    {
      struct stat outstat;
      if (stat (outfile, &outstat) == 0)
        {
          /* The following code prevents a race condition when
             people use the brain dead shell programming idiom:
                  cat file | sort -o file
             This feature is provided for historical compatibility,
             but we strongly discourage ever relying on this in
             new shell programs. */

          /* Temporarily copy each input file that might be another name
             for the output file.  When in doubt (e.g. a pipe), copy.  */
          for (i = 0; i < nfiles; ++i)
            {
              char buf[8192];
              FILE *in_fp;
              FILE *out_fp;
              int cc;

              if (S_ISREG (outstat.st_mode) && !STREQ (outfile, files[i]))
                {
                  struct stat instat;
                  if ((STREQ (files[i], "-")
                       ? fstat (STDIN_FILENO, &instat)
                       : stat (files[i], &instat)) != 0)
                    {
                      error (0, errno, "%s", files[i]);
                      cleanup ();
                      exit (SORT_FAILURE);
                    }
                  if (S_ISREG (instat.st_mode) && !SAME_INODE (instat, outstat))
                    {
                      /* We know the files are distinct.  */
                      continue;
                    }
                }

              in_fp = xfopen (files[i], "r");
              tmp = tempname ();
              out_fp = xtmpfopen (tmp);
              /* FIXME: maybe use copy.c(copy) here. */
              while ((cc = fread (buf, 1, sizeof buf, in_fp)) > 0)
                write_bytes (buf, cc, out_fp);
              if (ferror (in_fp))
                {
                  error (0, errno, "%s", files[i]);
                  cleanup ();
                  exit (SORT_FAILURE);
                }
              xfclose (out_fp);
              xfclose (in_fp);
              files[i] = tmp;
            }
          ofp = xfopen (outfile, "w");
        }
      else
        {
          /* A non-`-' outfile was specified, but the file doesn't yet exist.
             Before opening it for writing (thus creating it), make sure all
             of the input files exist.  Otherwise, creating the output file
             could create an otherwise missing input file, making sort succeed
             when it should fail.  */
          for (i = 0; i < nfiles; ++i)
            {
              struct stat sb;
              if (STREQ (files[i], "-"))
                continue;
              if (stat (files[i], &sb))
                {
                  error (0, errno, "%s", files[i]);
                  cleanup ();
                  exit (SORT_FAILURE);
                }
            }

          ofp = xfopen (outfile, "w");
        }
    }
  else
    {
      ofp = stdout;
    }

  if (mergeonly)
    merge (files, nfiles, ofp);
  else
    sort (files, nfiles, ofp);
  cleanup ();

  /* If we wait for the implicit flush on exit, and the parent process
     has closed stdout (e.g., exec >&- in a shell), then the output file
     winds up empty.  I don't understand why.  This is under SunOS,
     Solaris, Ultrix, and Irix.  This premature fflush makes the output
     reappear. --karl@cs.umb.edu  */
  if (fflush (ofp) < 0)
    error (SORT_FAILURE, errno, _("%s: write error"), outfile);

  if (have_read_stdin && fclose (stdin) == EOF)
    error (SORT_FAILURE, errno, "%s", outfile);
  if (ferror (stdout) || fclose (stdout) == EOF)
    error (SORT_FAILURE, errno, _("%s: write error"), outfile);

  exit (EXIT_SUCCESS);
}