cleanpatch: a script to clean up stealth whitespace added by a patch

[uclinux-h8/linux.git] / scripts / cleanpatch

diff --git a/scripts/cleanpatch b/scripts/cleanpatch
new file mode 100755 (executable)
index 0000000..a53f987
--- /dev/null
+++ b/scripts/cleanpatch
@@ -0,0 +1,206 @@
+#!/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;
+
+#
+# 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 $lo;
+}
+
+$name = basename($0);
+
+foreach $f ( @ARGV ) {
+    print STDERR "$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;
+
+    @lines  = ();
+
+    $in_hunk = 0;
+    $err = 0;
+
+    while ( defined($line = <FILE>) ) {
+       $in_bytes += length($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);
+
+               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);
+}