58 lines
1.3 KiB
Lua
58 lines
1.3 KiB
Lua
local scroller = {}
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local calc_count_fn = function(sorting_strategy)
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if sorting_strategy == 'ascending' then
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return function(a, b) return math.min(a, b) end
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else
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return function(a, b, row)
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if a == b or not row then
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return math.max(a, b)
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else
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local x = a - b
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if row < x then
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return math.max(a, b) - 1, true
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elseif row == a then
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return x, true
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else
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return math.max(a, b)
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end
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end
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end
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end
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end
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scroller.create = function(strategy, sorting_strategy)
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local calc_count = calc_count_fn(sorting_strategy)
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if strategy == 'cycle' then
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return function(max_results, num_results, row)
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local count, b = calc_count(max_results, num_results, row)
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if b then return count end
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if row >= count then
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return 0
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elseif row < 0 then
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return count - 1
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end
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return row
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end
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elseif strategy == 'limit' or strategy == nil then
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return function(max_results, num_results, row)
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local count = calc_count(max_results, num_results)
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if row >= count then
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return count - 1
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elseif row < 0 then
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return 0
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end
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return row
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end
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else
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error("Unsupported strategy: " .. strategy)
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end
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end
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return scroller
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