Initial revision

1 files changed, 221 insertions, 0 deletions

diff --git a/src/comm.c b/src/comm.c
new file mode 100644
index 000000000..4362b6475
--- /dev/null
+++ b/src/comm.c
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+/* comm -- compare two sorted files line by line.
+   Copyright (C) 1986, 1990, 1991 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* Written by Richard Stallman and David MacKenzie. */
+
+#include <stdio.h>
+#include <getopt.h>
+#include <sys/types.h>
+#include "system.h"
+#include "linebuffer.h"
+
+#define min(x, y) ((x) < (y) ? (x) : (y))
+
+/* If nonzero, print lines that are found only in file 1. */
+int only_file_1;
+
+/* If nonzero, print lines that are found only in file 2. */
+int only_file_2;
+
+/* If nonzero, print lines that are found in both files. */
+int both;
+
+/* The name this program was run with. */
+char *program_name;
+
+int compare_files ();
+void error ();
+void writeline ();
+void usage ();
+
+void
+main (argc, argv)
+     int argc;
+     char *argv[];
+{
+  int c;
+
+  program_name = argv[0];
+
+  only_file_1 = 1;
+  only_file_2 = 1;
+  both = 1;
+
+  while ((c = getopt (argc, argv, "123")) != EOF)
+    switch (c)
+      {
+      case '1':
+	only_file_1 = 0;
+	break;
+
+      case '2':
+	only_file_2 = 0;
+	break;
+
+      case '3':
+	both = 0;
+	break;
+
+      default:
+	usage ();
+      }
+
+  if (optind + 2 != argc)
+    usage ();
+
+  exit (compare_files (argv + optind));
+}
+
+/* Compare INFILES[0] and INFILES[1].
+   If either is "-", use the standard input for that file.
+   Assume that each input file is sorted;
+   merge them and output the result.
+   Return 0 if successful, 1 if any errors occur. */
+
+int
+compare_files (infiles)
+     char **infiles;
+{
+  /* For each file, we have one linebuffer in lb1.  */
+  struct linebuffer lb1[2];
+
+  /* thisline[i] points to the linebuffer holding the next available line
+     in file i, or is NULL if there are no lines left in that file.  */
+  struct linebuffer *thisline[2];
+
+  /* streams[i] holds the input stream for file i.  */
+  FILE *streams[2];
+
+  int i, ret = 0;
+
+  /* Initialize the storage. */
+  for (i = 0; i < 2; i++)
+    {
+      initbuffer (&lb1[i]);
+      thisline[i] = &lb1[i];
+      streams[i] = strcmp (infiles[i], "-")
+	? fopen (infiles[i], "r") : stdin;
+      if (!streams[i])
+	{
+	  error (0, errno, "%s", infiles[i]);
+	  return 1;
+	}
+
+      thisline[i] = readline (thisline[i], streams[i]);
+    }
+
+  while (thisline[0] || thisline[1])
+    {
+      int order;
+
+      /* Compare the next available lines of the two files.  */
+
+      if (!thisline[0])
+	order = 1;
+      else if (!thisline[1])
+	order = -1;
+      else
+	{
+	  /* Cannot use bcmp -- it only returns a boolean value. */
+	  order = memcmp (thisline[0]->buffer, thisline[1]->buffer,
+			  min (thisline[0]->length, thisline[1]->length));
+	  if (order == 0)
+	    order = thisline[0]->length - thisline[1]->length;
+	}
+
+      /* Output the line that is lesser. */
+      if (order == 0)
+	writeline (thisline[1], stdout, 3);
+      else if (order > 0)
+	writeline (thisline[1], stdout, 2);
+      else
+	writeline (thisline[0], stdout, 1);
+
+      /* Step the file the line came from.
+	 If the files match, step both files.  */
+      if (order >= 0)
+	thisline[1] = readline (thisline[1], streams[1]);
+      if (order <= 0)
+	thisline[0] = readline (thisline[0], streams[0]);
+    }
+
+  /* Free all storage and close all input streams. */
+  for (i = 0; i < 2; i++)
+    {
+      free (lb1[i].buffer);
+      if (ferror (streams[i]) || fclose (streams[i]) == EOF)
+	{
+	  error (0, errno, "%s", infiles[i]);
+	  ret = 1;
+	}
+    }
+  if (ferror (stdout) || fclose (stdout) == EOF)
+    {
+      error (0, errno, "write error");
+      ret = 1;
+    }
+  return ret;
+}
+
+/* Output the line in linebuffer LINE to stream STREAM
+   provided the switches say it should be output.
+   CLASS is 1 for a line found only in file 1,
+   2 for a line only in file 2, 3 for a line in both. */
+
+void
+writeline (line, stream, class)
+     struct linebuffer *line;
+     FILE *stream;
+     int class;
+{
+  switch (class)
+    {
+    case 1:
+      if (!only_file_1)
+	return;
+      break;
+
+    case 2:
+      if (!only_file_2)
+	return;
+      /* Skip the tab stop for case 1, if we are printing case 1.  */
+      if (only_file_1)
+	putc ('\t', stream);
+      break;
+
+    case 3:
+      if (!both)
+	return;
+      /* Skip the tab stop for case 1, if we are printing case 1.  */
+      if (only_file_1)
+	putc ('\t', stream);
+      /* Skip the tab stop for case 2, if we are printing case 2.  */
+      if (only_file_2)
+	putc ('\t', stream);
+      break;
+    }
+
+  fwrite (line->buffer, sizeof (char), line->length, stream);
+  putc ('\n', stream);
+}
+
+void
+usage ()
+{
+  fprintf (stderr, "Usage: %s [-123] file1 file2\n", program_name);
+  exit (1);
+}