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path: root/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/planar/List.lua
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-rw-r--r--Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/planar/List.lua49
1 files changed, 49 insertions, 0 deletions
diff --git a/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/planar/List.lua b/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/planar/List.lua
new file mode 100644
index 00000000000..564216a8c37
--- /dev/null
+++ b/Master/texmf-dist/tex/generic/pgf/graphdrawing/lua/pgf/gd/planar/List.lua
@@ -0,0 +1,49 @@
+local List = {}
+
+List.__index = List
+
+function List.new()
+ local t = {first = 0, last = -1}
+ setmetatable(t, List)
+ return t
+end
+
+function List:pushleft(value)
+ local first = self.first - 1
+ self.first = first
+ self[first] = value
+end
+
+function List:pushright(value)
+ local last = self.last + 1
+ self.last = last
+ self[last] = value
+end
+
+function List:popleft()
+ local first = self.first
+ if first > self.last then error("List is empty") end
+ local value = self[first]
+ self[first] = nil
+ self.first = first + 1
+ return value
+end
+
+function List:popright()
+ local last = self.last
+ if self.first > last then error("List is empty") end
+ local value = self[last]
+ self[last] = nil
+ self.last = last - 1
+ return value
+end
+
+function List:size()
+ return self.last - self.first + 1
+end
+
+function List:empty()
+ return self.last < self.first
+end
+
+return List