Adding upstream version 9.1.upstream/9.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1202 insertions, 0 deletions

diff --git a/src/join.c b/src/join.c
new file mode 100644
index 0000000..f2fd172
--- /dev/null
+++ b/src/join.c
@@ -0,0 +1,1202 @@
+/* join - join lines of two files on a common field
+   Copyright (C) 1991-2022 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 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/>.
+
+   Written by Mike Haertel, mike@gnu.ai.mit.edu.  */
+
+#include <config.h>
+
+#include <assert.h>
+#include <sys/types.h>
+#include <getopt.h>
+
+#include "system.h"
+#include "die.h"
+#include "error.h"
+#include "fadvise.h"
+#include "hard-locale.h"
+#include "linebuffer.h"
+#include "memcasecmp.h"
+#include "quote.h"
+#include "stdio--.h"
+#include "xmemcoll.h"
+#include "xstrtol.h"
+#include "argmatch.h"
+
+/* The official name of this program (e.g., no 'g' prefix).  */
+#define PROGRAM_NAME "join"
+
+#define AUTHORS proper_name ("Mike Haertel")
+
+#define join system_join
+
+#define SWAPLINES(a, b) do { \
+  struct line *tmp = a; \
+  a = b; \
+  b = tmp; \
+} while (0);
+
+/* An element of the list identifying which fields to print for each
+   output line.  */
+struct outlist
+  {
+    /* File number: 0, 1, or 2.  0 means use the join field.
+       1 means use the first file argument, 2 the second.  */
+    int file;
+
+    /* Field index (zero-based), specified only when FILE is 1 or 2.  */
+    size_t field;
+
+    struct outlist *next;
+  };
+
+/* A field of a line.  */
+struct field
+  {
+    char *beg;			/* First character in field.  */
+    size_t len;			/* The length of the field.  */
+  };
+
+/* A line read from an input file.  */
+struct line
+  {
+    struct linebuffer buf;	/* The line itself.  */
+    size_t nfields;		/* Number of elements in 'fields'.  */
+    size_t nfields_allocated;	/* Number of elements allocated for 'fields'. */
+    struct field *fields;
+  };
+
+/* One or more consecutive lines read from a file that all have the
+   same join field value.  */
+struct seq
+  {
+    size_t count;			/* Elements used in 'lines'.  */
+    size_t alloc;			/* Elements allocated in 'lines'.  */
+    struct line **lines;
+  };
+
+/* The previous line read from each file.  */
+static struct line *prevline[2] = {NULL, NULL};
+
+/* The number of lines read from each file.  */
+static uintmax_t line_no[2] = {0, 0};
+
+/* The input file names.  */
+static char *g_names[2];
+
+/* This provides an extra line buffer for each file.  We need these if we
+   try to read two consecutive lines into the same buffer, since we don't
+   want to overwrite the previous buffer before we check order. */
+static struct line *spareline[2] = {NULL, NULL};
+
+/* True if the LC_COLLATE locale is hard.  */
+static bool hard_LC_COLLATE;
+
+/* If nonzero, print unpairable lines in file 1 or 2.  */
+static bool print_unpairables_1, print_unpairables_2;
+
+/* If nonzero, print pairable lines.  */
+static bool print_pairables;
+
+/* If nonzero, we have seen at least one unpairable line. */
+static bool seen_unpairable;
+
+/* If nonzero, we have warned about disorder in that file. */
+static bool issued_disorder_warning[2];
+
+/* Empty output field filler.  */
+static char const *empty_filler;
+
+/* Whether to ensure the same number of fields are output from each line.  */
+static bool autoformat;
+/* The number of fields to output for each line.
+   Only significant when autoformat is true.  */
+static size_t autocount_1;
+static size_t autocount_2;
+
+/* Field to join on; SIZE_MAX means they haven't been determined yet.  */
+static size_t join_field_1 = SIZE_MAX;
+static size_t join_field_2 = SIZE_MAX;
+
+/* List of fields to print.  */
+static struct outlist outlist_head;
+
+/* Last element in 'outlist', where a new element can be added.  */
+static struct outlist *outlist_end = &outlist_head;
+
+/* Tab character separating fields.  If negative, fields are separated
+   by any nonempty string of blanks, otherwise by exactly one
+   tab character whose value (when cast to unsigned char) equals TAB.  */
+static int tab = -1;
+
+/* If nonzero, check that the input is correctly ordered. */
+static enum
+  {
+    CHECK_ORDER_DEFAULT,
+    CHECK_ORDER_ENABLED,
+    CHECK_ORDER_DISABLED
+  } check_input_order;
+
+enum
+{
+  CHECK_ORDER_OPTION = CHAR_MAX + 1,
+  NOCHECK_ORDER_OPTION,
+  HEADER_LINE_OPTION
+};
+
+
+static struct option const longopts[] =
+{
+  {"ignore-case", no_argument, NULL, 'i'},
+  {"check-order", no_argument, NULL, CHECK_ORDER_OPTION},
+  {"nocheck-order", no_argument, NULL, NOCHECK_ORDER_OPTION},
+  {"zero-terminated", no_argument, NULL, 'z'},
+  {"header", no_argument, NULL, HEADER_LINE_OPTION},
+  {GETOPT_HELP_OPTION_DECL},
+  {GETOPT_VERSION_OPTION_DECL},
+  {NULL, 0, NULL, 0}
+};
+
+/* Used to print non-joining lines */
+static struct line uni_blank;
+
+/* If nonzero, ignore case when comparing join fields.  */
+static bool ignore_case;
+
+/* If nonzero, treat the first line of each file as column headers --
+   join them without checking for ordering */
+static bool join_header_lines;
+
+/* The character marking end of line. Default to \n. */
+static char eolchar = '\n';
+
+void
+usage (int status)
+{
+  if (status != EXIT_SUCCESS)
+    emit_try_help ();
+  else
+    {
+      printf (_("\
+Usage: %s [OPTION]... FILE1 FILE2\n\
+"),
+              program_name);
+      fputs (_("\
+For each pair of input lines with identical join fields, write a line to\n\
+standard output.  The default join field is the first, delimited by blanks.\
+\n\
+"), stdout);
+      fputs (_("\
+\n\
+When FILE1 or FILE2 (not both) is -, read standard input.\n\
+"), stdout);
+      fputs (_("\
+\n\
+  -a FILENUM             also print unpairable lines from file FILENUM, where\n\
+                           FILENUM is 1 or 2, corresponding to FILE1 or FILE2\n\
+"), stdout);
+      fputs (_("\
+  -e STRING              replace missing (empty) input fields with STRING;\n\
+                           I.e., missing fields specified with '-12jo' options\
+\n\
+"), stdout);
+      fputs (_("\
+  -i, --ignore-case      ignore differences in case when comparing fields\n\
+  -j FIELD               equivalent to '-1 FIELD -2 FIELD'\n\
+  -o FORMAT              obey FORMAT while constructing output line\n\
+  -t CHAR                use CHAR as input and output field separator\n\
+"), stdout);
+      fputs (_("\
+  -v FILENUM             like -a FILENUM, but suppress joined output lines\n\
+  -1 FIELD               join on this FIELD of file 1\n\
+  -2 FIELD               join on this FIELD of file 2\n\
+      --check-order      check that the input is correctly sorted, even\n\
+                           if all input lines are pairable\n\
+      --nocheck-order    do not check that the input is correctly sorted\n\
+      --header           treat the first line in each file as field headers,\n\
+                           print them without trying to pair them\n\
+"), stdout);
+      fputs (_("\
+  -z, --zero-terminated  line delimiter is NUL, not newline\n\
+"), stdout);
+      fputs (HELP_OPTION_DESCRIPTION, stdout);
+      fputs (VERSION_OPTION_DESCRIPTION, stdout);
+      fputs (_("\
+\n\
+Unless -t CHAR is given, leading blanks separate fields and are ignored,\n\
+else fields are separated by CHAR.  Any FIELD is a field number counted\n\
+from 1.  FORMAT is one or more comma or blank separated specifications,\n\
+each being 'FILENUM.FIELD' or '0'.  Default FORMAT outputs the join field,\n\
+the remaining fields from FILE1, the remaining fields from FILE2, all\n\
+separated by CHAR.  If FORMAT is the keyword 'auto', then the first\n\
+line of each file determines the number of fields output for each line.\n\
+\n\
+Important: FILE1 and FILE2 must be sorted on the join fields.\n\
+E.g., use \"sort -k 1b,1\" if 'join' has no options,\n\
+or use \"join -t ''\" if 'sort' has no options.\n\
+Note, comparisons honor the rules specified by 'LC_COLLATE'.\n\
+If the input is not sorted and some lines cannot be joined, a\n\
+warning message will be given.\n\
+"), stdout);
+      emit_ancillary_info (PROGRAM_NAME);
+    }
+  exit (status);
+}
+
+/* Record a field in LINE, with location FIELD and size LEN.  */
+
+static void
+extract_field (struct line *line, char *field, size_t len)
+{
+  if (line->nfields >= line->nfields_allocated)
+    {
+      line->fields = X2NREALLOC (line->fields, &line->nfields_allocated);
+    }
+  line->fields[line->nfields].beg = field;
+  line->fields[line->nfields].len = len;
+  ++(line->nfields);
+}
+
+/* Fill in the 'fields' structure in LINE.  */
+
+static void
+xfields (struct line *line)
+{
+  char *ptr = line->buf.buffer;
+  char const *lim = ptr + line->buf.length - 1;
+
+  if (ptr == lim)
+    return;
+
+  if (0 <= tab && tab != '\n')
+    {
+      char *sep;
+      for (; (sep = memchr (ptr, tab, lim - ptr)) != NULL; ptr = sep + 1)
+        extract_field (line, ptr, sep - ptr);
+    }
+  else if (tab < 0)
+    {
+      /* Skip leading blanks before the first field.  */
+      while (field_sep (*ptr))
+        if (++ptr == lim)
+          return;
+
+      do
+        {
+          char *sep;
+          for (sep = ptr + 1; sep != lim && ! field_sep (*sep); sep++)
+            continue;
+          extract_field (line, ptr, sep - ptr);
+          if (sep == lim)
+            return;
+          for (ptr = sep + 1; ptr != lim && field_sep (*ptr); ptr++)
+            continue;
+        }
+      while (ptr != lim);
+    }
+
+  extract_field (line, ptr, lim - ptr);
+}
+
+static void
+freeline (struct line *line)
+{
+  if (line == NULL)
+    return;
+  free (line->fields);
+  line->fields = NULL;
+  free (line->buf.buffer);
+  line->buf.buffer = NULL;
+}
+
+/* Return <0 if the join field in LINE1 compares less than the one in LINE2;
+   >0 if it compares greater; 0 if it compares equal.
+   Report an error and exit if the comparison fails.
+   Use join fields JF_1 and JF_2 respectively.  */
+
+static int
+keycmp (struct line const *line1, struct line const *line2,
+        size_t jf_1, size_t jf_2)
+{
+  /* Start of field to compare in each file.  */
+  char *beg1;
+  char *beg2;
+
+  size_t len1;
+  size_t len2;		/* Length of fields to compare.  */
+  int diff;
+
+  if (jf_1 < line1->nfields)
+    {
+      beg1 = line1->fields[jf_1].beg;
+      len1 = line1->fields[jf_1].len;
+    }
+  else
+    {
+      beg1 = NULL;
+      len1 = 0;
+    }
+
+  if (jf_2 < line2->nfields)
+    {
+      beg2 = line2->fields[jf_2].beg;
+      len2 = line2->fields[jf_2].len;
+    }
+  else
+    {
+      beg2 = NULL;
+      len2 = 0;
+    }
+
+  if (len1 == 0)
+    return len2 == 0 ? 0 : -1;
+  if (len2 == 0)
+    return 1;
+
+  if (ignore_case)
+    {
+      /* FIXME: ignore_case does not work with NLS (in particular,
+         with multibyte chars).  */
+      diff = memcasecmp (beg1, beg2, MIN (len1, len2));
+    }
+  else
+    {
+      if (hard_LC_COLLATE)
+        return xmemcoll (beg1, len1, beg2, len2);
+      diff = memcmp (beg1, beg2, MIN (len1, len2));
+    }
+
+  if (diff)
+    return diff;
+  return len1 < len2 ? -1 : len1 != len2;
+}
+
+/* Check that successive input lines PREV and CURRENT from input file
+   WHATFILE are presented in order, unless the user may be relying on
+   the GNU extension that input lines may be out of order if no input
+   lines are unpairable.
+
+   If the user specified --nocheck-order, the check is not made.
+   If the user specified --check-order, the problem is fatal.
+   Otherwise (the default), the message is simply a warning.
+
+   A message is printed at most once per input file. */
+
+static void
+check_order (const struct line *prev,
+             const struct line *current,
+             int whatfile)
+{
+  if (check_input_order != CHECK_ORDER_DISABLED
+      && ((check_input_order == CHECK_ORDER_ENABLED) || seen_unpairable))
+    {
+      if (!issued_disorder_warning[whatfile - 1])
+        {
+          size_t join_field = whatfile == 1 ? join_field_1 : join_field_2;
+          if (keycmp (prev, current, join_field, join_field) > 0)
+            {
+              /* Exclude any trailing newline. */
+              size_t len = current->buf.length;
+              if (0 < len && current->buf.buffer[len - 1] == '\n')
+                --len;
+
+              /* If the offending line is longer than INT_MAX, output
+                 only the first INT_MAX bytes in this diagnostic.  */
+              len = MIN (INT_MAX, len);
+
+              error ((check_input_order == CHECK_ORDER_ENABLED
+                      ? EXIT_FAILURE : 0),
+                     0, _("%s:%"PRIuMAX": is not sorted: %.*s"),
+                     g_names[whatfile - 1], line_no[whatfile - 1],
+                     (int) len, current->buf.buffer);
+
+              /* If we get to here, the message was merely a warning.
+                 Arrange to issue it only once per file.  */
+              issued_disorder_warning[whatfile - 1] = true;
+            }
+        }
+    }
+}
+
+static inline void
+reset_line (struct line *line)
+{
+  line->nfields = 0;
+}
+
+static struct line *
+init_linep (struct line **linep)
+{
+  struct line *line = xcalloc (1, sizeof *line);
+  *linep = line;
+  return line;
+}
+
+/* Read a line from FP into LINE and split it into fields.
+   Return true if successful.  */
+
+static bool
+get_line (FILE *fp, struct line **linep, int which)
+{
+  struct line *line = *linep;
+
+  if (line == prevline[which - 1])
+    {
+      SWAPLINES (line, spareline[which - 1]);
+      *linep = line;
+    }
+
+  if (line)
+    reset_line (line);
+  else
+    line = init_linep (linep);
+
+  if (! readlinebuffer_delim (&line->buf, fp, eolchar))
+    {
+      if (ferror (fp))
+        die (EXIT_FAILURE, errno, _("read error"));
+      freeline (line);
+      return false;
+    }
+  ++line_no[which - 1];
+
+  xfields (line);
+
+  if (prevline[which - 1])
+    check_order (prevline[which - 1], line, which);
+
+  prevline[which - 1] = line;
+  return true;
+}
+
+static void
+free_spareline (void)
+{
+  for (size_t i = 0; i < ARRAY_CARDINALITY (spareline); i++)
+    {
+      if (spareline[i])
+        {
+          freeline (spareline[i]);
+          free (spareline[i]);
+        }
+    }
+}
+
+static void
+initseq (struct seq *seq)
+{
+  seq->count = 0;
+  seq->alloc = 0;
+  seq->lines = NULL;
+}
+
+/* Read a line from FP and add it to SEQ.  Return true if successful.  */
+
+static bool
+getseq (FILE *fp, struct seq *seq, int whichfile)
+{
+  if (seq->count == seq->alloc)
+    {
+      seq->lines = X2NREALLOC (seq->lines, &seq->alloc);
+      for (size_t i = seq->count; i < seq->alloc; i++)
+        seq->lines[i] = NULL;
+    }
+
+  if (get_line (fp, &seq->lines[seq->count], whichfile))
+    {
+      ++seq->count;
+      return true;
+    }
+  return false;
+}
+
+/* Read a line from FP and add it to SEQ, as the first item if FIRST is
+   true, else as the next.  */
+static bool
+advance_seq (FILE *fp, struct seq *seq, bool first, int whichfile)
+{
+  if (first)
+    seq->count = 0;
+
+  return getseq (fp, seq, whichfile);
+}
+
+static void
+delseq (struct seq *seq)
+{
+  for (size_t i = 0; i < seq->alloc; i++)
+    {
+      freeline (seq->lines[i]);
+      free (seq->lines[i]);
+    }
+  free (seq->lines);
+}
+
+
+/* Print field N of LINE if it exists and is nonempty, otherwise
+   'empty_filler' if it is nonempty.  */
+
+static void
+prfield (size_t n, struct line const *line)
+{
+  size_t len;
+
+  if (n < line->nfields)
+    {
+      len = line->fields[n].len;
+      if (len)
+        fwrite (line->fields[n].beg, 1, len, stdout);
+      else if (empty_filler)
+        fputs (empty_filler, stdout);
+    }
+  else if (empty_filler)
+    fputs (empty_filler, stdout);
+}
+
+/* Output all the fields in line, other than the join field.  */
+
+static void
+prfields (struct line const *line, size_t join_field, size_t autocount)
+{
+  size_t i;
+  size_t nfields = autoformat ? autocount : line->nfields;
+  char output_separator = tab < 0 ? ' ' : tab;
+
+  for (i = 0; i < join_field && i < nfields; ++i)
+    {
+      putchar (output_separator);
+      prfield (i, line);
+    }
+  for (i = join_field + 1; i < nfields; ++i)
+    {
+      putchar (output_separator);
+      prfield (i, line);
+    }
+}
+
+/* Print the join of LINE1 and LINE2.  */
+
+static void
+prjoin (struct line const *line1, struct line const *line2)
+{
+  const struct outlist *outlist;
+  char output_separator = tab < 0 ? ' ' : tab;
+  size_t field;
+  struct line const *line;
+
+  outlist = outlist_head.next;
+  if (outlist)
+    {
+      const struct outlist *o;
+
+      o = outlist;
+      while (true)
+        {
+          if (o->file == 0)
+            {
+              if (line1 == &uni_blank)
+                {
+                  line = line2;
+                  field = join_field_2;
+                }
+              else
+                {
+                  line = line1;
+                  field = join_field_1;
+                }
+            }
+          else
+            {
+              line = (o->file == 1 ? line1 : line2);
+              field = o->field;
+            }
+          prfield (field, line);
+          o = o->next;
+          if (o == NULL)
+            break;
+          putchar (output_separator);
+        }
+      putchar (eolchar);
+    }
+  else
+    {
+      if (line1 == &uni_blank)
+        {
+          line = line2;
+          field = join_field_2;
+        }
+      else
+        {
+          line = line1;
+          field = join_field_1;
+        }
+
+      /* Output the join field.  */
+      prfield (field, line);
+
+      /* Output other fields.  */
+      prfields (line1, join_field_1, autocount_1);
+      prfields (line2, join_field_2, autocount_2);
+
+      putchar (eolchar);
+    }
+}
+
+/* Print the join of the files in FP1 and FP2.  */
+
+static void
+join (FILE *fp1, FILE *fp2)
+{
+  struct seq seq1, seq2;
+  int diff;
+  bool eof1, eof2;
+
+  fadvise (fp1, FADVISE_SEQUENTIAL);
+  fadvise (fp2, FADVISE_SEQUENTIAL);
+
+  /* Read the first line of each file.  */
+  initseq (&seq1);
+  getseq (fp1, &seq1, 1);
+  initseq (&seq2);
+  getseq (fp2, &seq2, 2);
+
+  if (autoformat)
+    {
+      autocount_1 = seq1.count ? seq1.lines[0]->nfields : 0;
+      autocount_2 = seq2.count ? seq2.lines[0]->nfields : 0;
+    }
+
+  if (join_header_lines && (seq1.count || seq2.count))
+    {
+      struct line const *hline1 = seq1.count ? seq1.lines[0] : &uni_blank;
+      struct line const *hline2 = seq2.count ? seq2.lines[0] : &uni_blank;
+      prjoin (hline1, hline2);
+      prevline[0] = NULL;
+      prevline[1] = NULL;
+      if (seq1.count)
+        advance_seq (fp1, &seq1, true, 1);
+      if (seq2.count)
+        advance_seq (fp2, &seq2, true, 2);
+    }
+
+  while (seq1.count && seq2.count)
+    {
+      diff = keycmp (seq1.lines[0], seq2.lines[0],
+                     join_field_1, join_field_2);
+      if (diff < 0)
+        {
+          if (print_unpairables_1)
+            prjoin (seq1.lines[0], &uni_blank);
+          advance_seq (fp1, &seq1, true, 1);
+          seen_unpairable = true;
+          continue;
+        }
+      if (diff > 0)
+        {
+          if (print_unpairables_2)
+            prjoin (&uni_blank, seq2.lines[0]);
+          advance_seq (fp2, &seq2, true, 2);
+          seen_unpairable = true;
+          continue;
+        }
+
+      /* Keep reading lines from file1 as long as they continue to
+         match the current line from file2.  */
+      eof1 = false;
+      do
+        if (!advance_seq (fp1, &seq1, false, 1))
+          {
+            eof1 = true;
+            ++seq1.count;
+            break;
+          }
+      while (!keycmp (seq1.lines[seq1.count - 1], seq2.lines[0],
+                      join_field_1, join_field_2));
+
+      /* Keep reading lines from file2 as long as they continue to
+         match the current line from file1.  */
+      eof2 = false;
+      do
+        if (!advance_seq (fp2, &seq2, false, 2))
+          {
+            eof2 = true;
+            ++seq2.count;
+            break;
+          }
+      while (!keycmp (seq1.lines[0], seq2.lines[seq2.count - 1],
+                      join_field_1, join_field_2));
+
+      if (print_pairables)
+        {
+          for (size_t i = 0; i < seq1.count - 1; ++i)
+            {
+              size_t j;
+              for (j = 0; j < seq2.count - 1; ++j)
+                prjoin (seq1.lines[i], seq2.lines[j]);
+            }
+        }
+
+      if (!eof1)
+        {
+          SWAPLINES (seq1.lines[0], seq1.lines[seq1.count - 1]);
+          seq1.count = 1;
+        }
+      else
+        seq1.count = 0;
+
+      if (!eof2)
+        {
+          SWAPLINES (seq2.lines[0], seq2.lines[seq2.count - 1]);
+          seq2.count = 1;
+        }
+      else
+        seq2.count = 0;
+    }
+
+  /* If the user did not specify --nocheck-order, then we read the
+     tail ends of both inputs to verify that they are in order.  We
+     skip the rest of the tail once we have issued a warning for that
+     file, unless we actually need to print the unpairable lines.  */
+  struct line *line = NULL;
+  bool checktail = false;
+
+  if (check_input_order != CHECK_ORDER_DISABLED
+      && !(issued_disorder_warning[0] && issued_disorder_warning[1]))
+    checktail = true;
+
+  if ((print_unpairables_1 || checktail) && seq1.count)
+    {
+      if (print_unpairables_1)
+        prjoin (seq1.lines[0], &uni_blank);
+      if (seq2.count)
+        seen_unpairable = true;
+      while (get_line (fp1, &line, 1))
+        {
+          if (print_unpairables_1)
+            prjoin (line, &uni_blank);
+          if (issued_disorder_warning[0] && !print_unpairables_1)
+            break;
+        }
+    }
+
+  if ((print_unpairables_2 || checktail) && seq2.count)
+    {
+      if (print_unpairables_2)
+        prjoin (&uni_blank, seq2.lines[0]);
+      if (seq1.count)
+        seen_unpairable = true;
+      while (get_line (fp2, &line, 2))
+        {
+          if (print_unpairables_2)
+            prjoin (&uni_blank, line);
+          if (issued_disorder_warning[1] && !print_unpairables_2)
+            break;
+        }
+    }
+
+  freeline (line);
+  free (line);
+
+  delseq (&seq1);
+  delseq (&seq2);
+}
+
+/* Add a field spec for field FIELD of file FILE to 'outlist'.  */
+
+static void
+add_field (int file, size_t field)
+{
+  struct outlist *o;
+
+  assert (file == 0 || file == 1 || file == 2);
+  assert (file != 0 || field == 0);
+
+  o = xmalloc (sizeof *o);
+  o->file = file;
+  o->field = field;
+  o->next = NULL;
+
+  /* Add to the end of the list so the fields are in the right order.  */
+  outlist_end->next = o;
+  outlist_end = o;
+}
+
+/* Convert a string of decimal digits, STR (the 1-based join field number),
+   to an integral value.  Upon successful conversion, return one less
+   (the zero-based field number).  Silently convert too-large values
+   to SIZE_MAX - 1.  Otherwise, if a value cannot be converted, give a
+   diagnostic and exit.  */
+
+static size_t
+string_to_join_field (char const *str)
+{
+  size_t result;
+  uintmax_t val;
+
+  strtol_error s_err = xstrtoumax (str, NULL, 10, &val, "");
+  if (s_err == LONGINT_OVERFLOW || (s_err == LONGINT_OK && SIZE_MAX < val))
+    val = SIZE_MAX;
+  else if (s_err != LONGINT_OK || val == 0)
+    die (EXIT_FAILURE, 0, _("invalid field number: %s"), quote (str));
+
+  result = val - 1;
+
+  return result;
+}
+
+/* Convert a single field specifier string, S, to a *FILE_INDEX, *FIELD_INDEX
+   pair.  In S, the field index string is 1-based; *FIELD_INDEX is zero-based.
+   If S is valid, return true.  Otherwise, give a diagnostic and exit.  */
+
+static void
+decode_field_spec (char const *s, int *file_index, size_t *field_index)
+{
+  /* The first character must be 0, 1, or 2.  */
+  switch (s[0])
+    {
+    case '0':
+      if (s[1])
+        {
+          /* '0' must be all alone -- no '.FIELD'.  */
+          die (EXIT_FAILURE, 0, _("invalid field specifier: %s"), quote (s));
+        }
+      *file_index = 0;
+      *field_index = 0;
+      break;
+
+    case '1':
+    case '2':
+      if (s[1] != '.')
+        die (EXIT_FAILURE, 0, _("invalid field specifier: %s"), quote (s));
+      *file_index = s[0] - '0';
+      *field_index = string_to_join_field (s + 2);
+      break;
+
+    default:
+      die (EXIT_FAILURE, 0,
+           _("invalid file number in field spec: %s"), quote (s));
+
+      /* Tell gcc -W -Wall that we can't get beyond this point.
+         This avoids a warning (otherwise legit) that the caller's copies
+         of *file_index and *field_index might be used uninitialized.  */
+      abort ();
+
+      break;
+    }
+}
+
+/* Add the comma or blank separated field spec(s) in STR to 'outlist'.  */
+
+static void
+add_field_list (char *str)
+{
+  char *p = str;
+
+  do
+    {
+      int file_index;
+      size_t field_index;
+      char const *spec_item = p;
+
+      p = strpbrk (p, ", \t");
+      if (p)
+        *p++ = '\0';
+      decode_field_spec (spec_item, &file_index, &field_index);
+      add_field (file_index, field_index);
+    }
+  while (p);
+}
+
+/* Set the join field *VAR to VAL, but report an error if *VAR is set
+   more than once to incompatible values.  */
+
+static void
+set_join_field (size_t *var, size_t val)
+{
+  if (*var != SIZE_MAX && *var != val)
+    {
+      unsigned long int var1 = *var + 1;
+      unsigned long int val1 = val + 1;
+      die (EXIT_FAILURE, 0,
+           _("incompatible join fields %lu, %lu"), var1, val1);
+    }
+  *var = val;
+}
+
+/* Status of command-line arguments.  */
+
+enum operand_status
+  {
+    /* This argument must be an operand, i.e., one of the files to be
+       joined.  */
+    MUST_BE_OPERAND,
+
+    /* This might be the argument of the preceding -j1 or -j2 option,
+       or it might be an operand.  */
+    MIGHT_BE_J1_ARG,
+    MIGHT_BE_J2_ARG,
+
+    /* This might be the argument of the preceding -o option, or it might be
+       an operand.  */
+    MIGHT_BE_O_ARG
+  };
+
+/* Add NAME to the array of input file NAMES with operand statuses
+   OPERAND_STATUS; currently there are NFILES names in the list.  */
+
+static void
+add_file_name (char *name, char *names[2],
+               int operand_status[2], int joption_count[2], int *nfiles,
+               int *prev_optc_status, int *optc_status)
+{
+  int n = *nfiles;
+
+  if (n == 2)
+    {
+      bool op0 = (operand_status[0] == MUST_BE_OPERAND);
+      char *arg = names[op0];
+      switch (operand_status[op0])
+        {
+        case MUST_BE_OPERAND:
+          error (0, 0, _("extra operand %s"), quoteaf (name));
+          usage (EXIT_FAILURE);
+
+        case MIGHT_BE_J1_ARG:
+          joption_count[0]--;
+          set_join_field (&join_field_1, string_to_join_field (arg));
+          break;
+
+        case MIGHT_BE_J2_ARG:
+          joption_count[1]--;
+          set_join_field (&join_field_2, string_to_join_field (arg));
+          break;
+
+        case MIGHT_BE_O_ARG:
+          add_field_list (arg);
+          break;
+        }
+      if (!op0)
+        {
+          operand_status[0] = operand_status[1];
+          names[0] = names[1];
+        }
+      n = 1;
+    }
+
+  operand_status[n] = *prev_optc_status;
+  names[n] = name;
+  *nfiles = n + 1;
+  if (*prev_optc_status == MIGHT_BE_O_ARG)
+    *optc_status = MIGHT_BE_O_ARG;
+}
+
+int
+main (int argc, char **argv)
+{
+  int optc_status;
+  int prev_optc_status = MUST_BE_OPERAND;
+  int operand_status[2];
+  int joption_count[2] = { 0, 0 };
+  FILE *fp1, *fp2;
+  int optc;
+  int nfiles = 0;
+  int i;
+
+  initialize_main (&argc, &argv);
+  set_program_name (argv[0]);
+  setlocale (LC_ALL, "");
+  bindtextdomain (PACKAGE, LOCALEDIR);
+  textdomain (PACKAGE);
+  hard_LC_COLLATE = hard_locale (LC_COLLATE);
+
+  atexit (close_stdout);
+  atexit (free_spareline);
+
+  print_pairables = true;
+  seen_unpairable = false;
+  issued_disorder_warning[0] = issued_disorder_warning[1] = false;
+  check_input_order = CHECK_ORDER_DEFAULT;
+
+  while ((optc = getopt_long (argc, argv, "-a:e:i1:2:j:o:t:v:z",
+                              longopts, NULL))
+         != -1)
+    {
+      optc_status = MUST_BE_OPERAND;
+
+      switch (optc)
+        {
+        case 'v':
+            print_pairables = false;
+            FALLTHROUGH;
+
+        case 'a':
+          {
+            unsigned long int val;
+            if (xstrtoul (optarg, NULL, 10, &val, "") != LONGINT_OK
+                || (val != 1 && val != 2))
+              die (EXIT_FAILURE, 0,
+                   _("invalid field number: %s"), quote (optarg));
+            if (val == 1)
+              print_unpairables_1 = true;
+            else
+              print_unpairables_2 = true;
+          }
+          break;
+
+        case 'e':
+          if (empty_filler && ! STREQ (empty_filler, optarg))
+            die (EXIT_FAILURE, 0,
+                 _("conflicting empty-field replacement strings"));
+          empty_filler = optarg;
+          break;
+
+        case 'i':
+          ignore_case = true;
+          break;
+
+        case '1':
+          set_join_field (&join_field_1, string_to_join_field (optarg));
+          break;
+
+        case '2':
+          set_join_field (&join_field_2, string_to_join_field (optarg));
+          break;
+
+        case 'j':
+          if ((optarg[0] == '1' || optarg[0] == '2') && !optarg[1]
+              && optarg == argv[optind - 1] + 2)
+            {
+              /* The argument was either "-j1" or "-j2".  */
+              bool is_j2 = (optarg[0] == '2');
+              joption_count[is_j2]++;
+              optc_status = MIGHT_BE_J1_ARG + is_j2;
+            }
+          else
+            {
+              set_join_field (&join_field_1, string_to_join_field (optarg));
+              set_join_field (&join_field_2, join_field_1);
+            }
+          break;
+
+        case 'o':
+          if (STREQ (optarg, "auto"))
+            autoformat = true;
+          else
+            {
+              add_field_list (optarg);
+              optc_status = MIGHT_BE_O_ARG;
+            }
+          break;
+
+        case 't':
+          {
+            unsigned char newtab = optarg[0];
+            if (! newtab)
+              newtab = '\n'; /* '' => process the whole line.  */
+            else if (optarg[1])
+              {
+                if (STREQ (optarg, "\\0"))
+                  newtab = '\0';
+                else
+                  die (EXIT_FAILURE, 0, _("multi-character tab %s"),
+                       quote (optarg));
+              }
+            if (0 <= tab && tab != newtab)
+              die (EXIT_FAILURE, 0, _("incompatible tabs"));
+            tab = newtab;
+          }
+          break;
+
+        case 'z':
+          eolchar = 0;
+          break;
+
+        case NOCHECK_ORDER_OPTION:
+          check_input_order = CHECK_ORDER_DISABLED;
+          break;
+
+        case CHECK_ORDER_OPTION:
+          check_input_order = CHECK_ORDER_ENABLED;
+          break;
+
+        case 1:		/* Non-option argument.  */
+          add_file_name (optarg, g_names, operand_status, joption_count,
+                         &nfiles, &prev_optc_status, &optc_status);
+          break;
+
+        case HEADER_LINE_OPTION:
+          join_header_lines = true;
+          break;
+
+        case_GETOPT_HELP_CHAR;
+
+        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+        default:
+          usage (EXIT_FAILURE);
+        }
+
+      prev_optc_status = optc_status;
+    }
+
+  /* Process any operands after "--".  */
+  prev_optc_status = MUST_BE_OPERAND;
+  while (optind < argc)
+    add_file_name (argv[optind++], g_names, operand_status, joption_count,
+                   &nfiles, &prev_optc_status, &optc_status);
+
+  if (nfiles != 2)
+    {
+      if (nfiles == 0)
+        error (0, 0, _("missing operand"));
+      else
+        error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
+      usage (EXIT_FAILURE);
+    }
+
+  /* If "-j1" was specified and it turns out not to have had an argument,
+     treat it as "-j 1".  Likewise for -j2.  */
+  for (i = 0; i < 2; i++)
+    if (joption_count[i] != 0)
+      {
+        set_join_field (&join_field_1, i);
+        set_join_field (&join_field_2, i);
+      }
+
+  if (join_field_1 == SIZE_MAX)
+    join_field_1 = 0;
+  if (join_field_2 == SIZE_MAX)
+    join_field_2 = 0;
+
+  fp1 = STREQ (g_names[0], "-") ? stdin : fopen (g_names[0], "r");
+  if (!fp1)
+    die (EXIT_FAILURE, errno, "%s", quotef (g_names[0]));
+  fp2 = STREQ (g_names[1], "-") ? stdin : fopen (g_names[1], "r");
+  if (!fp2)
+    die (EXIT_FAILURE, errno, "%s", quotef (g_names[1]));
+  if (fp1 == fp2)
+    die (EXIT_FAILURE, errno, _("both files cannot be standard input"));
+  join (fp1, fp2);
+
+  if (fclose (fp1) != 0)
+    die (EXIT_FAILURE, errno, "%s", quotef (g_names[0]));
+  if (fclose (fp2) != 0)
+    die (EXIT_FAILURE, errno, "%s", quotef (g_names[1]));
+
+  if (issued_disorder_warning[0] || issued_disorder_warning[1])
+    die (EXIT_FAILURE, 0, _("input is not in sorted order"));
+  else
+    return EXIT_SUCCESS;
+}