78 lines
2 KiB
Elixir
78 lines
2 KiB
Elixir
defmodule RangeUtil do
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@spec from_start(integer(), integer()) :: Range.t()
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def from_start(start, len) do
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if len == 0 do
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..
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else
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start..(start + len - 1)
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end
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end
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def transpose(value, source, dest) do
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offset = value - (source |> Enum.at(0))
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(dest |> Enum.at(0)) + offset
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end
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@spec contains?(Range.t(), Range.t()) :: boolean
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def contains?(r1, r2) do
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r2.first >= r1.first and r2.last <= r1.last
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end
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@spec difference(Range.t(), Range.t()) :: [Range.t()]
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def difference(r1, r2) do
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cond do
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Range.disjoint?(r1, r2) ->
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[r1]
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RangeUtil.contains?(r2, r1) ->
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[]
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RangeUtil.contains?(r1, r2) ->
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s1_len = r2.first - r1.first
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s2_len = r1.last - r2.last
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[
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RangeUtil.from_start(r1.first, s1_len),
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RangeUtil.from_start(r2.last + 1, s2_len)
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]
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|> Enum.reject(fn r -> r == .. end)
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r2.first <= r1.first and r2.last <= r1.last ->
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s1_len = r1.last - r2.last
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[RangeUtil.from_start(r2.last + 1, s1_len)]
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r2.first >= r1.first and r2.last >= r1.last ->
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s1_len = r2.first - r1.first
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[RangeUtil.from_start(r1.first, s1_len)]
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end
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end
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@spec intersection(Range.t(), Range.t()) :: Range.t()
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def intersection(r1, r2) do
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cond do
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Range.disjoint?(r1, r2) -> ..
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RangeUtil.contains?(r2, r1) -> r1
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RangeUtil.contains?(r1, r2) -> r2
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r2.first <= r1.first and r2.last <= r1.last -> Range.new(r1.first, r2.last)
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r2.first >= r1.first and r2.last >= r1.last -> Range.new(r2.first, r1.last)
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end
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end
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@spec split_at(range :: Range.t(), value :: integer(), bound :: :lb | :ub) :: [Range.t()]
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def split_at(range, value, bound) do
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if value <= range.first or value >= range.last do
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[range]
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else
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ls = min(range.first, value - 1)
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le = min(range.last, value - 1)
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rs = max(range.first, value + 1)
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re = max(range.last, value + 1)
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if bound == :lb do
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[ls..value, rs..re]
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else
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[ls..le, value..re]
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end
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end
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end
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end
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