FreeBSD/Linux Kernel Cross Reference
sys/scripts/cleanpatch

     #!/usr/bin/perl -w
     #
     # Clean a patch file -- or directory of patch files -- of stealth whitespace.
     # WARNING: this can be a highly destructive operation.  Use with caution.
     #
     
     use bytes;
     use File::Basename;
     
    # Default options
    $max_width = 79;
    
    # Clean up space-tab sequences, either by removing spaces or
    # replacing them with tabs.
    sub clean_space_tabs($)
    {
        no bytes;                   # Tab alignment depends on characters
    
        my($li) = @_;
        my($lo) = '';
        my $pos = 0;
        my $nsp = 0;
        my($i, $c);
    
        for ($i = 0; $i < length($li); $i++) {
            $c = substr($li, $i, 1);
            if ($c eq "\t") {
                my $npos = ($pos+$nsp+8) & ~7;
                my $ntab = ($npos >> 3) - ($pos >> 3);
                $lo .= "\t" x $ntab;
                $pos = $npos;
                $nsp = 0;
            } elsif ($c eq "\n" || $c eq "\r") {
                $lo .= " " x $nsp;
                $pos += $nsp;
                $nsp = 0;
                $lo .= $c;
                $pos = 0;
            } elsif ($c eq " ") {
                $nsp++;
            } else {
                $lo .= " " x $nsp;
                $pos += $nsp;
                $nsp = 0;
                $lo .= $c;
                $pos++;
            }
        }
        $lo .= " " x $nsp;
        return $lo;
    }
    
    # Compute the visual width of a string
    sub strwidth($) {
        no bytes;                   # Tab alignment depends on characters
    
        my($li) = @_;
        my($c, $i);
        my $pos = 0;
        my $mlen = 0;
    
        for ($i = 0; $i < length($li); $i++) {
            $c = substr($li,$i,1);
            if ($c eq "\t") {
                $pos = ($pos+8) & ~7;
            } elsif ($c eq "\n") {
                $mlen = $pos if ($pos > $mlen);
                $pos = 0;
            } else {
                $pos++;
            }
        }
    
        $mlen = $pos if ($pos > $mlen);
        return $mlen;
    }
    
    $name = basename($0);
    
    @files = ();
    
    while (defined($a = shift(@ARGV))) {
        if ($a =~ /^-/) {
            if ($a eq '-width' || $a eq '-w') {
                $max_width = shift(@ARGV)+0;
            } else {
                print STDERR "Usage: $name [-width #] files...\n";
                exit 1;
            }
        } else {
            push(@files, $a);
        }
    }
    
    foreach $f ( @files ) {
        print STDERR "$name: $f\n";
    
        if (! -f $f) {
            print STDERR "$f: not a file\n";
           next;
       }
   
       if (!open(FILE, '+<', $f)) {
           print STDERR "$name: Cannot open file: $f: $!\n";
           next;
       }
   
       binmode FILE;
   
       # First, verify that it is not a binary file; consider any file
       # with a zero byte to be a binary file.  Is there any better, or
       # additional, heuristic that should be applied?
       $is_binary = 0;
   
       while (read(FILE, $data, 65536) > 0) {
           if ($data =~ /\0/) {
               $is_binary = 1;
               last;
           }
       }
   
       if ($is_binary) {
           print STDERR "$name: $f: binary file\n";
           next;
       }
   
       seek(FILE, 0, 0);
   
       $in_bytes = 0;
       $out_bytes = 0;
       $lineno = 0;
   
       @lines  = ();
   
       $in_hunk = 0;
       $err = 0;
   
       while ( defined($line = <FILE>) ) {
           $lineno++;
           $in_bytes += length($line);
   
           if (!$in_hunk) {
               if ($line =~
                   /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@/) {
                   $minus_lines = $2;
                   $plus_lines = $4;
                   if ($minus_lines || $plus_lines) {
                       $in_hunk = 1;
                       @hunk_lines = ($line);
                   }
               } else {
                   push(@lines, $line);
                   $out_bytes += length($line);
               }
           } else {
               # We're in a hunk
   
               if ($line =~ /^\+/) {
                   $plus_lines--;
   
                   $text = substr($line, 1);
                   $text =~ s/[ \t\r]*$//;         # Remove trailing spaces
                   $text = clean_space_tabs($text);
   
                   $l_width = strwidth($text);
                   if ($max_width && $l_width > $max_width) {
                       print STDERR
                           "$f:$lineno: adds line exceeds $max_width ",
                           "characters ($l_width)\n";
                   }
   
                   push(@hunk_lines, '+'.$text);
               } elsif ($line =~ /^\-/) {
                   $minus_lines--;
                   push(@hunk_lines, $line);
               } elsif ($line =~ /^ /) {
                   $plus_lines--;
                   $minus_lines--;
                   push(@hunk_lines, $line);
               } else {
                   print STDERR "$name: $f: malformed patch\n";
                   $err = 1;
                   last;
               }
   
               if ($plus_lines < 0 || $minus_lines < 0) {
                   print STDERR "$name: $f: malformed patch\n";
                   $err = 1;
                   last;
               } elsif ($plus_lines == 0 && $minus_lines == 0) {
                   # End of a hunk.  Process this hunk.
                   my $i;
                   my $l;
                   my @h = ();
                   my $adj = 0;
                   my $done = 0;
   
                   for ($i = scalar(@hunk_lines)-1; $i > 0; $i--) {
                       $l = $hunk_lines[$i];
                       if (!$done && $l eq "+\n") {
                           $adj++; # Skip this line
                       } elsif ($l =~ /^[ +]/) {
                           $done = 1;
                           unshift(@h, $l);
                       } else {
                           unshift(@h, $l);
                       }
                   }
   
                   $l = $hunk_lines[0];  # Hunk header
                   undef @hunk_lines;    # Free memory
   
                   if ($adj) {
                       die unless
                           ($l =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@(.*)$/);
                       my $mstart = $1;
                       my $mlin = $2;
                       my $pstart = $3;
                       my $plin = $4;
                       my $tail = $5; # doesn't include the final newline
   
                       $l = sprintf("@@ -%d,%d +%d,%d @@%s\n",
                                    $mstart, $mlin, $pstart, $plin-$adj,
                                    $tail);
                   }
                   unshift(@h, $l);
   
                   # Transfer to the output array
                   foreach $l (@h) {
                       $out_bytes += length($l);
                       push(@lines, $l);
                   }
   
                   $in_hunk = 0;
               }
           }
       }
   
       if ($in_hunk) {
           print STDERR "$name: $f: malformed patch\n";
           $err = 1;
       }
   
       if (!$err) {
           if ($in_bytes != $out_bytes) {
               # Only write to the file if changed
               seek(FILE, 0, 0);
               print FILE @lines;
   
               if ( !defined($where = tell(FILE)) ||
                    !truncate(FILE, $where) ) {
                   die "$name: Failed to truncate modified file: $f: $!\n";
               }
           }
       }
   
       close(FILE);
   }

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