util.c

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

		  if (c1 == ' ' && c2 != '\n'
		      && s2 + 1 < t2
		      && isspace ((unsigned char) t2[-2]))
		    {
		      --t2;
		      continue;
		    }
		}

	      break;

	    case IGNORE_TAB_EXPANSION:
	      if ((c1 == ' ' && c2 == '\t')
		  || (c1 == '\t' && c2 == ' '))
		{
		  size_t column2 = column;
		  for (;; c1 = *t1++)
		    {
		      if (c1 == ' ')
			column++;
		      else if (c1 == '\t')
			column += tabsize - column % tabsize;
		      else
			break;
		    }
		  for (;; c2 = *t2++)
		    {
		      if (c2 == ' ')
			column2++;
		      else if (c2 == '\t')
			column2 += tabsize - column2 % tabsize;
		      else
			break;
		    }
		  if (column != column2)
		    return true;
		}
	      break;

	    case IGNORE_NO_WHITE_SPACE:
	      break;
	    }

	  /* Lowercase all letters if -i is specified.  */

	  if (ignore_case)
	    {
	      c1 = tolower (c1);
	      c2 = tolower (c2);
	    }

	  if (c1 != c2)
	    break;
	}
      if (c1 == '\n')
	return false;

      column += c1 == '\t' ? tabsize - column % tabsize : 1;
    }

  return true;
}

/* Find the consecutive changes at the start of the script START.
   Return the last link before the first gap.  */

struct change *
find_change (struct change *start)
{
  return start;
}

struct change *
find_reverse_change (struct change *start)
{
  return start;
}

/* Divide SCRIPT into pieces by calling HUNKFUN and
   print each piece with PRINTFUN.
   Both functions take one arg, an edit script.

   HUNKFUN is called with the tail of the script
   and returns the last link that belongs together with the start
   of the tail.

   PRINTFUN takes a subscript which belongs together (with a null
   link at the end) and prints it.  */

void
print_script (struct change *script,
	      struct change * (*hunkfun) (struct change *),
	      void (*printfun) (struct change *))
{
  struct change *next = script;

  while (next)
    {
      struct change *this, *end;

      /* Find a set of changes that belong together.  */
      this = next;
      end = (*hunkfun) (next);

      /* Disconnect them from the rest of the changes,
	 making them a hunk, and remember the rest for next iteration.  */
      next = end->link;
      end->link = 0;
#ifdef DEBUG
      debug_script (this);
#endif

      /* Print this hunk.  */
      (*printfun) (this);

      /* Reconnect the script so it will all be freed properly.  */
      end->link = next;
    }
}

/* Print the text of a single line LINE,
   flagging it with the characters in LINE_FLAG (which say whether
   the line is inserted, deleted, changed, etc.).  */

void
print_1_line (char const *line_flag, char const *const *line)
{
  char const *base = line[0], *limit = line[1]; /* Help the compiler.  */
  FILE *out = outfile; /* Help the compiler some more.  */
  char const *flag_format = 0;

  /* If -T was specified, use a Tab between the line-flag and the text.
     Otherwise use a Space (as Unix diff does).
     Print neither space nor tab if line-flags are empty.  */

  if (line_flag && *line_flag)
    {
      flag_format = initial_tab ? "%s\t" : "%s ";
      fprintf (out, flag_format, line_flag);
    }

  output_1_line (base, limit, flag_format, line_flag);

  if ((!line_flag || line_flag[0]) && limit[-1] != '\n')
    fprintf (out, "\n\\ %s\n", _("No newline at end of file"));
}

/* Output a line from BASE up to LIMIT.
   With -t, expand white space characters to spaces, and if FLAG_FORMAT
   is nonzero, output it with argument LINE_FLAG after every
   internal carriage return, so that tab stops continue to line up.  */

void
output_1_line (char const *base, char const *limit, char const *flag_format,
	       char const *line_flag)
{
  if (!expand_tabs)
    fwrite (base, sizeof (char), limit - base, outfile);
  else
    {
      register FILE *out = outfile;
      register unsigned char c;
      register char const *t = base;
      register size_t column = 0;
      size_t tab_size = tabsize;

      while (t < limit)
	switch ((c = *t++))
	  {
	  case '\t':
	    {
	      size_t spaces = tab_size - column % tab_size;
	      column += spaces;
	      do
		putc (' ', out);
	      while (--spaces);
	    }
	    break;

	  case '\r':
	    putc (c, out);
	    if (flag_format && t < limit && *t != '\n')
	      fprintf (out, flag_format, line_flag);
	    column = 0;
	    break;

	  case '\b':
	    if (column == 0)
	      continue;
	    column--;
	    putc (c, out);
	    break;

	  default:
	    column += isprint (c) != 0;
	    putc (c, out);
	    break;
	  }
    }
}

char const change_letter[] = { 0, 'd', 'a', 'c' };

/* Translate an internal line number (an index into diff's table of lines)
   into an actual line number in the input file.
   The internal line number is I.  FILE points to the data on the file.

   Internal line numbers count from 0 starting after the prefix.
   Actual line numbers count from 1 within the entire file.  */

lin
translate_line_number (struct file_data const *file, lin i)
{
  return i + file->prefix_lines + 1;
}

/* Translate a line number range.  This is always done for printing,
   so for convenience translate to long int rather than lin, so that the
   caller can use printf with "%ld" without casting.  */

void
translate_range (struct file_data const *file,
		 lin a, lin b,
		 long int *aptr, long int *bptr)
{
  *aptr = translate_line_number (file, a - 1) + 1;
  *bptr = translate_line_number (file, b + 1) - 1;
}

/* Print a pair of line numbers with SEPCHAR, translated for file FILE.
   If the two numbers are identical, print just one number.

   Args A and B are internal line numbers.
   We print the translated (real) line numbers.  */

void
print_number_range (char sepchar, struct file_data *file, lin a, lin b)
{
  long int trans_a, trans_b;
  translate_range (file, a, b, &trans_a, &trans_b);

  /* Note: we can have B < A in the case of a range of no lines.
     In this case, we should print the line number before the range,
     which is B.  */
  if (trans_b > trans_a)
    fprintf (outfile, "%ld%c%ld", trans_a, sepchar, trans_b);
  else
    fprintf (outfile, "%ld", trans_b);
}

/* Look at a hunk of edit script and report the range of lines in each file
   that it applies to.  HUNK is the start of the hunk, which is a chain
   of `struct change'.  The first and last line numbers of file 0 are stored in
   *FIRST0 and *LAST0, and likewise for file 1 in *FIRST1 and *LAST1.
   Note that these are internal line numbers that count from 0.

   If no lines from file 0 are deleted, then FIRST0 is LAST0+1.

   Return UNCHANGED if only ignorable lines are inserted or deleted,
   OLD if lines of file 0 are deleted,
   NEW if lines of file 1 are inserted,
   and CHANGED if both kinds of changes are found. */

enum changes
analyze_hunk (struct change *hunk,
	      lin *first0, lin *last0,
	      lin *first1, lin *last1)
{
  struct change *next;
  lin l0, l1;
  lin show_from, show_to;
  lin i;
  bool trivial = ignore_blank_lines || ignore_regexp.fastmap;
  size_t trivial_length = ignore_blank_lines - 1;
    /* If 0, ignore zero-length lines;
       if SIZE_MAX, do not ignore lines just because of their length.  */
  bool skip_leading_white_space =
    (ignore_blank_lines && IGNORE_SPACE_CHANGE <= ignore_white_space);

  char const * const *linbuf0 = files[0].linbuf;  /* Help the compiler.  */
  char const * const *linbuf1 = files[1].linbuf;

  show_from = show_to = 0;

  *first0 = hunk->line0;
  *first1 = hunk->line1;

  next = hunk;
  do
    {
      l0 = next->line0 + next->deleted - 1;
      l1 = next->line1 + next->inserted - 1;
      show_from += next->deleted;
      show_to += next->inserted;

      for (i = next->line0; i <= l0 && trivial; i++)
	{
	  char const *line = linbuf0[i];
	  char const *newline = linbuf0[i + 1] - 1;
	  size_t len = newline - line;
	  char const *p = line;
	  if (skip_leading_white_space)
	    while (isspace ((unsigned char) *p) && *p != '\n')
	      p++;
	  if (newline - p != trivial_length
	      && (! ignore_regexp.fastmap
		  || re_search (&ignore_regexp, line, len, 0, len, 0) < 0))
	    trivial = 0;
	}

      for (i = next->line1; i <= l1 && trivial; i++)
	{
	  char const *line = linbuf1[i];
	  char const *newline = linbuf1[i + 1] - 1;
	  size_t len = newline - line;
	  char const *p = line;
	  if (skip_leading_white_space)
	    while (isspace ((unsigned char) *p) && *p != '\n')
	      p++;
	  if (newline - p != trivial_length
	      && (! ignore_regexp.fastmap
		  || re_search (&ignore_regexp, line, len, 0, len, 0) < 0))
	    trivial = 0;
	}
    }
  while ((next = next->link) != 0);

  *last0 = l0;
  *last1 = l1;

  /* If all inserted or deleted lines are ignorable,
     tell the caller to ignore this hunk.  */

  if (trivial)
    return UNCHANGED;

  return (show_from ? OLD : UNCHANGED) | (show_to ? NEW : UNCHANGED);
}

/* Concatenate three strings, returning a newly malloc'd string.  */

char *
concat (char const *s1, char const *s2, char const *s3)
{
  char *new = xmalloc (strlen (s1) + strlen (s2) + strlen (s3) + 1);
  sprintf (new, "%s%s%s", s1, s2, s3);
  return new;
}

/* Yield a new block of SIZE bytes, initialized to zero.  */

void *
zalloc (size_t size)
{
  void *p = xmalloc (size);
  memset (p, 0, size);
  return p;
}

/* Yield the newly malloc'd pathname
   of the file in DIR whose filename is FILE.  */

char *
dir_file_pathname (char const *dir, char const *file)
{
  char const *base = base_name (dir);
  bool omit_slash = !*base || base[strlen (base) - 1] == '/';
  return concat (dir, "/" + omit_slash, file);
}

void
debug_script (struct change *sp)
{
  fflush (stdout);

  for (; sp; sp = sp->link)
    {
      long int line0 = sp->line0;
      long int line1 = sp->line1;
      long int deleted = sp->deleted;
      long int inserted = sp->inserted;
      fprintf (stderr, "%3ld %3ld delete %ld insert %ld\n",
	       line0, line1, deleted, inserted);
    }

  fflush (stderr);
}