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-rw-r--r--lib/puppet/parser/functions/shuffle.rb46
1 files changed, 46 insertions, 0 deletions
diff --git a/lib/puppet/parser/functions/shuffle.rb b/lib/puppet/parser/functions/shuffle.rb
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+++ b/lib/puppet/parser/functions/shuffle.rb
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+#
+# shuffle.rb
+#
+
+module Puppet::Parser::Functions
+ newfunction(:shuffle, :type => :rvalue, :doc => <<-EOS
+Randomizes the order of a string or array elements.
+ EOS
+ ) do |arguments|
+
+ raise(Puppet::ParseError, "shuffle(): Wrong number of arguments " +
+ "given (#{arguments.size} for 1)") if arguments.size < 1
+
+ value = arguments[0]
+ klass = value.class
+
+ unless [Array, String].include?(klass)
+ raise(Puppet::ParseError, 'shuffle(): Requires either ' +
+ 'array or string to work with')
+ end
+
+ result = value.clone
+
+ string = value.is_a?(String) ? true : false
+
+ # Check whether it makes sense to shuffle ...
+ return result if result.size <= 1
+
+ # We turn any string value into an array to be able to shuffle ...
+ result = string ? result.split('') : result
+
+ elements = result.size
+
+ # Simple implementation of Fisher–Yates in-place shuffle ...
+ elements.times do |i|
+ j = rand(elements - i) + i
+ result[j], result[i] = result[i], result[j]
+ end
+
+ result = string ? result.join : result
+
+ return result
+ end
+end
+
+# vim: set ts=2 sw=2 et :