From 41781058476180e060339e9065eeee18365d6c38 Mon Sep 17 00:00:00 2001
From: Ward Wouts <ward@wouts.nl>
Date: Tue, 31 Jul 2001 11:50:31 +0000
Subject: [PATCH] regels wisselen kan nu ook

---
 mvwrap/mvwrap | 127 ++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 103 insertions(+), 24 deletions(-)

diff --git a/mvwrap/mvwrap b/mvwrap/mvwrap
index 3de8061..fe693ae 100755
--- a/mvwrap/mvwrap
+++ b/mvwrap/mvwrap
@@ -1,8 +1,9 @@
 #!/usr/bin/perl -w
 
 #
-# Scriptje om een editor op de inhoud van directories los te laten.
-# Makkelijker dan 6000 keer move met de hand doen.
+# Script to let an editor loose on a directory listing
+# Much easier than doing 6000 moves by hand
+# I think it's relatively safe now
 # (C) 2001 Ward Wouts
 #
 
@@ -19,9 +20,10 @@ while ( defined ($filename = readdir(DIRHANDLE)) ) {
 	push @dir, "$filename\n";
 }
 closedir(DIRHANDLE);
-@source= sort @dir;
+@source = sort @dir;
 if ($DEBUG) { print @source; }
 
+
 # make tempfiles and install handler to remove them
 do { $target_name = tmpnam() }
 	until $target = IO::File->new($target_name, O_RDWR|O_CREAT|O_EXCL);
@@ -30,41 +32,62 @@ END { unlink($target_name) or die "Couldn't unlink $target_name: $!" }
 foreach (@source) {
 	print $target $_;
 }
-
 close ($target);
 
-$editor = defined $ENV{EDITOR}  ? $ENV{EDITOR} : "vi";
-@editor = ("$editor", "$target_name");
-system(@editor) == 0
-	or die "System @editor failed: $?";
+&edit($target_name);
 
-open $target, $target_name;
-while (<$target>) {
-	push @target, $_;
-}
+open $target, $target_name or die "Couldn't open tempfile: $target_name: $!";
+@target = <$target>;
 close ($target);
+
 if ($DEBUG) { print @target; }
 
 unless ( scalar(@source) == scalar(@target) ) {
 	die "Aborting. Source and target list don't have the same number of lines.\n";
 }
 
-if (&check_unique(@target)) {
+if ( &check_unique(@target) ) {
 	die "Aborting. You're trying to move multiple files to the same name.\n";
 }
 
-$i=0;
-while ( $i < scalar(@source) ) {
-	$source=$source[$i];
-	chomp($source);
-	$target=$target[$i];
-	chomp($target);
-	unless ( $source eq $target ) {
-		if ($DEBUG) { print "mv $source $target\n"; }
-		move("$source", "$target")
-			or die "move failed: $!";
+# if it's unsafe to move files directly, move the unsafe ones to a
+# temporary file first
+if (@unsafe = &check_safety(\@source, \@target)) {
+	&safety_belt(\@unsafe, \@source);
+}
+
+# final move
+&move_files(\@source, \@target);
+
+# call EDITOR or vi with filename
+sub edit {
+	my $filename = shift;
+	$editor = defined $ENV{EDITOR}  ? $ENV{EDITOR} : "vi";
+	@editor = ("$editor", "$filename");
+	system(@editor) == 0
+		or die "System @editor failed: $?";
+}
+
+# moves files from the names in one array to the names in another array
+# must be called like:
+# move_files(\@source, \@target)
+sub move_files {
+	my ($from, $to) = @_;
+	my($i, $source, $target);
+	$i=0;
+	while ( $i < scalar(@$from) ) {
+		$source=$from->[$i];
+		chomp($source);
+		$target=$to->[$i];
+		chomp($target);
+		unless ( $source eq $target ) {
+			if ($DEBUG) { print "mv $source $target\n"; }
+			move("$source", "$target")
+				or die "move failed: $!";
+		}
+		$i++;
 	}
-	$i++;
+	return 1;
 }
 
 # returns 0 if all entries in @target_list are unique. 1 if not.
@@ -78,3 +101,59 @@ sub check_unique (@target_list){
 	}
 	return 0;
 }
+
+# compares one array of file names to another, making sure files
+# can be moved safely without overwriting each other
+# must be called like:
+# check_safety(\@source, \@target)
+# returns an array of unsafe line numbers
+sub check_safety {
+	my ($from, $to) = @_;
+	my($i, $j, $source, $target, @danger);
+	$i=0;
+	while ( $i < scalar(@$from) ) {
+		$source=$from->[$i];
+		chomp($source);
+		$j=0;
+		while ( $j < scalar(@$to) ) {
+			$target=$to->[$j];
+			chomp($target);
+			if (($source eq $target) && ($i != $j)) {
+				push @danger, $i;
+			}
+			$j++;
+		}
+	$i++;
+	}
+	return @danger;
+}
+
+# generate random filename, which does not exist
+sub rand_file {
+	my (@chars, $filename, $exists);
+	@chars=( "A" .. "Z", "a" .. "z", 0 .. 9);
+	$exists = 1;
+	while ($exists) {
+		$filename = join("", @chars[ map { rand @chars } ( 1 .. 8 ) ]);
+		$exists = -e $filename;
+	}
+	
+	return $filename;
+}
+
+# moves files to a random filename and updates
+# the source array
+# must be called like:
+# safety_belt(\@unsafe, \@source)
+sub safety_belt {
+	my ($unsafe, $source) = @_;
+	my($filenr, $filename, $rand);
+	foreach $filenr (@$unsafe) {
+		$filename = $source->[$filenr];
+		chomp $filename;
+		$rand = &rand_file;
+		move("$filename", "$rand")
+				or die "move failed: $!";
+		$source->[$filenr] = "$rand\n";
+	}
+}