diff.c

制作2.6内核的CLFS时 使用的diffutils-2.8.7.tar.gz包

	  specify_value (&starting_file, optarg, "-S");
	  break;

	case 't':
	  expand_tabs = true;
	  break;

	case 'T':
	  initial_tab = true;
	  break;

	case 'u':
	  specify_style (OUTPUT_UNIFIED);
	  if (context < 3)
	    context = 3;
	  break;

	case 'v':
	  version_etc (stdout, "diff", PACKAGE_NAME, PACKAGE_VERSION,
		       "Paul Eggert", "Mike Haertel", "David Hayes",
		       "Richard Stallman", "Len Tower", (char *) 0);
	  check_stdout ();
	  return EXIT_SUCCESS;

	case 'w':
	  ignore_white_space = IGNORE_ALL_SPACE;
	  break;

	case 'x':
	  add_exclude (excluded, optarg, exclude_options ());
	  break;

	case 'X':
	  if (add_exclude_file (add_exclude, excluded, optarg,
				exclude_options (), '\n'))
	    pfatal_with_name (optarg);
	  break;

	case 'y':
	  specify_style (OUTPUT_SDIFF);
	  break;

	case 'W':
	  numval = strtoumax (optarg, &numend, 10);
	  if (! (0 < numval && numval <= SIZE_MAX) || *numend)
	    try_help ("invalid width `%s'", optarg);
	  if (width != numval)
	    {
	      if (width)
		fatal ("conflicting width options");
	      width = numval;
	    }
	  break;

	case BINARY_OPTION:
#if HAVE_SETMODE_DOS
	  binary = true;
	  set_binary_mode (STDOUT_FILENO, true);
#endif
	  break;

	case FROM_FILE_OPTION:
	  specify_value (&from_file, optarg, "--from-file");
	  break;

	case HELP_OPTION:
	  usage ();
	  check_stdout ();
	  return EXIT_SUCCESS;

	case HORIZON_LINES_OPTION:
	  numval = strtoumax (optarg, &numend, 10);
	  if (*numend)
	    try_help ("invalid horizon length `%s'", optarg);
	  horizon_lines = MAX (horizon_lines, MIN (numval, LIN_MAX));
	  break;

	case IGNORE_FILE_NAME_CASE_OPTION:
	  ignore_file_name_case = true;
	  break;

	case INHIBIT_HUNK_MERGE_OPTION:
	  /* This option is obsolete, but accept it for backward
             compatibility.  */
	  break;

	case LEFT_COLUMN_OPTION:
	  left_column = true;
	  break;

	case LINE_FORMAT_OPTION:
	  specify_style (OUTPUT_IFDEF);
	  for (i = 0; i < sizeof line_format / sizeof *line_format; i++)
	    specify_value (&line_format[i], optarg, "--line-format");
	  break;

	case NO_IGNORE_FILE_NAME_CASE_OPTION:
	  ignore_file_name_case = false;
	  break;

	case NORMAL_OPTION:
	  specify_style (OUTPUT_NORMAL);
	  break;

	case SDIFF_MERGE_ASSIST_OPTION:
	  specify_style (OUTPUT_SDIFF);
	  sdiff_merge_assist = true;
	  break;

	case STRIP_TRAILING_CR_OPTION:
	  strip_trailing_cr = true;
	  break;

	case SUPPRESS_COMMON_LINES_OPTION:
	  suppress_common_lines = true;
	  break;

	case TABSIZE_OPTION:
	  numval = strtoumax (optarg, &numend, 10);
	  if (! (0 < numval && numval <= SIZE_MAX) || *numend)
	    try_help ("invalid tabsize `%s'", optarg);
	  if (tabsize != numval)
	    {
	      if (tabsize)
		fatal ("conflicting tabsize options");
	      tabsize = numval;
	    }
	  break;

	case TO_FILE_OPTION:
	  specify_value (&to_file, optarg, "--to-file");
	  break;

	case UNCHANGED_LINE_FORMAT_OPTION:
	case OLD_LINE_FORMAT_OPTION:
	case NEW_LINE_FORMAT_OPTION:
	  specify_style (OUTPUT_IFDEF);
	  c -= UNCHANGED_LINE_FORMAT_OPTION;
	  specify_value (&line_format[c], optarg, line_format_option[c]);
	  break;

	case UNCHANGED_GROUP_FORMAT_OPTION:
	case OLD_GROUP_FORMAT_OPTION:
	case NEW_GROUP_FORMAT_OPTION:
	case CHANGED_GROUP_FORMAT_OPTION:
	  specify_style (OUTPUT_IFDEF);
	  c -= UNCHANGED_GROUP_FORMAT_OPTION;
	  specify_value (&group_format[c], optarg, group_format_option[c]);
	  break;

	default:
	  try_help (0, 0);
	}
      prev = c;
    }

  if (output_style == OUTPUT_UNSPECIFIED)
    {
      if (show_c_function)
	{
	  specify_style (OUTPUT_CONTEXT);
	  if (ocontext < 0)
	    context = 3;
	}
      else
	specify_style (OUTPUT_NORMAL);
    }

  if (output_style != OUTPUT_CONTEXT || hard_locale (LC_TIME))
    {
#ifdef ST_MTIM_NSEC
      time_format = "%Y-%m-%d %H:%M:%S.%N %z";
#else
      time_format = "%Y-%m-%d %H:%M:%S %z";
#endif
    }
  else
    {
      /* See POSIX 1003.1-2001 for this format.  */
      time_format = "%a %b %e %T %Y";
    }

  if (0 <= ocontext)
    {
      bool modern_usage = 200112 <= posix2_version ();

      if ((output_style == OUTPUT_CONTEXT
	   || output_style == OUTPUT_UNIFIED)
	  && (context < ocontext
	      || (ocontext < context && ! explicit_context)))
	{
	  if (modern_usage)
	    {
	      error (0, 0,
		     _("`-%ld' option is obsolete; use `-%c %ld'"),
		     (long int) ocontext,
		     output_style == OUTPUT_CONTEXT ? 'C' : 'U',
		     (long int) ocontext);
	      try_help (0, 0);
	    }
	  context = ocontext;
	}
      else
	{
	  if (modern_usage)
	    {
	      error (0, 0, _("`-%ld' option is obsolete; omit it"),
		     (long int) ocontext);
	      try_help (0, 0);
	    }
	}
    }

  if (! tabsize)
    tabsize = 8;
  if (! width)
    width = 130;

  {
    /* Maximize first the half line width, and then the gutter width,
       according to the following constraints:

	1.  Two half lines plus a gutter must fit in a line.
	2.  If the half line width is nonzero:
	    a.  The gutter width is at least GUTTER_WIDTH_MINIMUM.
	    b.  If tabs are not expanded to spaces,
		a half line plus a gutter is an integral number of tabs,
		so that tabs in the right column line up.  */

    intmax_t t = expand_tabs ? 1 : tabsize;
    intmax_t w = width;
    intmax_t off = (w + t + GUTTER_WIDTH_MINIMUM) / (2 * t)  *  t;
    sdiff_half_width = MAX (0, MIN (off - GUTTER_WIDTH_MINIMUM, w - off)),
    sdiff_column2_offset = sdiff_half_width ? off : w;
  }

  /* Make the horizon at least as large as the context, so that
     shift_boundaries has more freedom to shift the first and last hunks.  */
  if (horizon_lines < context)
    horizon_lines = context;

  summarize_regexp_list (&function_regexp_list);
  summarize_regexp_list (&ignore_regexp_list);

  if (output_style == OUTPUT_IFDEF)
    {
      for (i = 0; i < sizeof line_format / sizeof *line_format; i++)
	if (!line_format[i])
	  line_format[i] = "%l\n";
      if (!group_format[OLD])
	group_format[OLD]
	  = group_format[CHANGED] ? group_format[CHANGED] : "%<";
      if (!group_format[NEW])
	group_format[NEW]
	  = group_format[CHANGED] ? group_format[CHANGED] : "%>";
      if (!group_format[UNCHANGED])
	group_format[UNCHANGED] = "%=";
      if (!group_format[CHANGED])
	group_format[CHANGED] = concat (group_format[OLD],
					group_format[NEW], "");
    }

  no_diff_means_no_output =
    (output_style == OUTPUT_IFDEF ?
      (!*group_format[UNCHANGED]
       || (strcmp (group_format[UNCHANGED], "%=") == 0
	   && !*line_format[UNCHANGED]))
     : (output_style != OUTPUT_SDIFF) | suppress_common_lines);

  files_can_be_treated_as_binary =
    (brief & binary
     & ~ (ignore_blank_lines | ignore_case | strip_trailing_cr
	  | (ignore_regexp_list.regexps || ignore_white_space)));

  switch_string = option_list (argv + 1, optind - 1);

  if (from_file)
    {
      if (to_file)
	fatal ("--from-file and --to-file both specified");
      else
	for (; optind < argc; optind++)
	  {
	    int status = compare_files ((struct comparison *) 0,
					from_file, argv[optind]);
	    if (exit_status < status)
	      exit_status = status;
	  }
    }
  else
    {
      if (to_file)
	for (; optind < argc; optind++)
	  {
	    int status = compare_files ((struct comparison *) 0,
					argv[optind], to_file);
	    if (exit_status < status)
	      exit_status = status;
	  }
      else
	{
	  if (argc - optind != 2)
	    {
	      if (argc - optind < 2)
		try_help ("missing operand after `%s'", argv[argc - 1]);
	      else
		try_help ("extra operand `%s'", argv[optind + 2]);
	    }

	  exit_status = compare_files ((struct comparison *) 0,
				       argv[optind], argv[optind + 1]);
	}
    }

  /* Print any messages that were saved up for last.  */
  print_message_queue ();

  check_stdout ();
  exit (exit_status);
  return exit_status;
}

/* Append to REGLIST the regexp PATTERN.  */

static void
add_regexp (struct regexp_list *reglist, char const *pattern)
{
  size_t patlen = strlen (pattern);
  char const *m = re_compile_pattern (pattern, patlen, reglist->buf);

  if (m != 0)
    error (0, 0, "%s: %s", pattern, m);
  else
    {
      char *regexps = reglist->regexps;
      size_t len = reglist->len;
      bool multiple_regexps = reglist->multiple_regexps = regexps != 0;
      size_t newlen = reglist->len = len + 2 * multiple_regexps + patlen;
      size_t size = reglist->size;

      if (size <= newlen)
	{
	  if (!size)
	    size = 1;

	  do size *= 2;
	  while (size <= newlen);

	  reglist->size = size;
	  reglist->regexps = regexps = xrealloc (regexps, size);
	}
      if (multiple_regexps)
	{
	  regexps[len++] = '\\';
	  regexps[len++] = '|';
	}
      memcpy (regexps + len, pattern, patlen + 1);
    }
}

/* Ensure that REGLIST represents the disjunction of its regexps.
   This is done here, rather than earlier, to avoid O(N^2) behavior.  */

static void
summarize_regexp_list (struct regexp_list *reglist)
{
  if (reglist->regexps)
    {
      /* At least one regexp was specified.  Allocate a fastmap for it.  */
      reglist->buf->fastmap = xmalloc (1 << CHAR_BIT);
      if (reglist->multiple_regexps)
	{
	  /* Compile the disjunction of the regexps.
	     (If just one regexp was specified, it is already compiled.)  */
	  char const *m = re_compile_pattern (reglist->regexps, reglist->len,
					      reglist->buf);
	  if (m != 0)
	    error (EXIT_TROUBLE, 0, "%s: %s", reglist->regexps, m);
	}
    }
}

static void
try_help (char const *reason_msgid, char const *operand)
{
  if (reason_msgid)
    error (0, 0, _(reason_msgid), operand);
  error (EXIT_TROUBLE, 0, _("Try `%s --help' for more information."),
	 program_name);
  abort ();
}

static void
check_stdout (void)
{
  if (ferror (stdout))
    fatal ("write failed");
  else if (fclose (stdout) != 0)
    pfatal_with_name (_("standard output"));
}

static char const * const option_help_msgid[] = {
  N_("Compare files line by line."),
  "",
  N_("-i  --ignore-case  Ignore case differences in file contents."),
  N_("--ignore-file-name-case  Ignore case when comparing file names."),
  N_("--no-ignore-file-name-case  Consider case when comparing file names."),
  N_("-E  --ignore-tab-expansion  Ignore changes due to tab expansion."),
  N_("-b  --ignore-space-change  Ignore changes in the amount of white space."),
  N_("-w  --ignore-all-space  Ignore all white space."),
  N_("-B  --ignore-blank-lines  Ignore changes whose lines are all blank."),
  N_("-I RE  --ignore-matching-lines=RE  Ignore changes whose lines all match RE."),
  N_("--strip-trailing-cr  Strip trailing carriage return on input."),
#if HAVE_SETMODE_DOS
  N_("--binary  Read and write data in binary mode."),
#endif
  N_("-a  --text  Treat all files as text."),
  "",
  N_("-c  -C NUM  --context[=NUM]  Output NUM (default 3) lines of copied context.\n\
-u  -U NUM  --unified[=NUM]  Output NUM (default 3) lines of unified context.\n\
  --label LABEL  Use LABEL instead of file name.\n\
  -p  --show-c-function  Show which C function each change is in.\n\
  -F RE  --show-function-line=RE  Show the most recent line matching RE."),
  N_("-q  --brief  Output only whether files differ."),
  N_("-e  --ed  Output an ed script."),
  N_("--normal  Output a normal diff."),
  N_("-n  --rcs  Output an RCS format diff."),
  N_("-y  --side-by-side  Output in two columns.\n\
  -W NUM  --width=NUM  Output at most NUM (default 130) print columns.\n\
  --left-column  Output only the left column of common lines.\n\
  --suppress-common-lines  Do not output common lines."),
  N_("-D NAME  --ifdef=NAME  Output merged file to show `#ifdef NAME' diffs."),
  N_("--GTYPE-group-format=GFMT  Similar, but format GTYPE input groups with GFMT."),
  N_("--line-format=LFMT  Similar, but format all input lines with LFMT."),
  N_("--LTYPE-line-format=LFMT  Similar, but format LTYPE input lines with LFMT."),
  N_("  LTYPE is `old', `new', or `unchanged'.  GTYPE is LTYPE or `changed'."),
  N_("  GFMT may contain:\n\
    %<  lines from FILE1\n\
    %>  lines from FILE2\n\
    %=  lines common to FILE1 and FILE2\n\
    %[-][WIDTH][.[PREC]]{doxX}LETTER  printf-style spec for LETTER\n\
      LETTERs are as follows for new group, lower case for old group:\n\
        F  first line number\n\
        L  last line number\n\
        N  number of lines = L-F+1\n\
        E  F-1\n\
        M  L+1"),
  N_("  LFMT may contain:\n\
    %L  contents of line\n\
    %l  contents of line, excluding any trailing newline\n\
    %[-][WIDTH][.[PREC]]{doxX}n  printf-style spec for input line number"),
  N_("  Either GFMT or LFMT may contain:\n\