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| -rw-r--r-- | shuffle.rb | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/shuffle.rb b/shuffle.rb new file mode 100644 index 0000000..d92a3cd --- /dev/null +++ b/shuffle.rb @@ -0,0 +1,35 @@ +# +# shuffle.rb +# + +module Puppet::Parser::Functions + newfunction(:shuffle, :type => :rvalue, :doc => <<-EOS + EOS + ) do |arguments| + + raise(Puppet::ParseError, "shuffle(): Wrong number of arguments " + + "given (#{arguments.size} for 1)") if arguments.size < 1 + + array = arguments[0] + + if not array.is_a?(Array) + raise(Puppet::ParseError, 'shuffle(): Requires an array to work with') + end + + return [] if array.size == 0 + return array if array.size <= 1 + + list = array.clone + elements = list.size + + # Simple implementation of Fisher–Yates in-place shuffle ... + elements.times do |i| + j = rand(elements - i) + i + list[j], list[i] = list[i], list[j] + end + + return list + end +end + +# vim: set ts=2 sw=2 et : |