84 lines
2.2 KiB
Lua
84 lines
2.2 KiB
Lua
---------------------------------------------------------------------------
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-- @author Uli Schlachter
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-- @copyright 2010 Uli Schlachter
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-- @release @AWESOME_VERSION@
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---------------------------------------------------------------------------
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local setmetatable = setmetatable
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local ipairs = ipairs
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local table = table
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local error = error
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module("gears.sort")
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local function less_than_comp(a, b)
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return a < b
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end
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-- Sort a table. This interface should be identical to table.sort().
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-- The difference to table.sort() is that this sort is stable.
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-- @param list The table to sort (we do an in-place sort!).
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-- @param comp Comparator used for the sorting
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function sort(list, comp)
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local comp = comp or less_than_comp
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-- A table could contain non-integer keys which we have to ignore.
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local num = 0
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for k, v in ipairs(list) do
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num = num + 1
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end
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if num <= 1 then
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-- Nothing to do
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return
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end
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-- Sort until everything is sorted :)
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local sorted = false
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local n = num
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while not sorted do
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sorted = true
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for i = 1, n - 1 do
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-- Two equal elements won't be swapped -> we are stable
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if comp(list[i+1], list[i]) then
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local tmp = list[i]
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list[i] = list[i+1]
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list[i+1] = tmp
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sorted = false
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end
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end
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-- The last element is now guaranteed to be in the right spot
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n = n - 1
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end
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end
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function test()
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local function test_one(t)
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local len = #t
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sort(t)
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if len ~= #t then
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error("Table lost entries during sort!")
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end
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if len > 1 then
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local cur = table.remove(t, 1)
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len = len - 1
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while len > 0 do
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local next = table.remove(t, 1)
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if cur > next then
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error("Table not sorted!")
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end
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cur = next
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len = len -1
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end
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end
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end
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test_one({1, 2, 3, 4, 5, 6})
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test_one({6, 5, 4, 3, 2, 1})
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return true
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end
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setmetatable(_M, { __call = function (_, ...) return sort(...) end })
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-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80
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