mirror of
https://github.com/vrld/hump.git
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95 lines
2.7 KiB
Lua
95 lines
2.7 KiB
Lua
--[[
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Copyright (c) 2010-2012 Matthias Richter
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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Except as contained in this notice, the name(s) of the above copyright holders
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shall not be used in advertising or otherwise to promote the sale, use or
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other dealings in this Software without prior written authorization.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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]]--
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local ringbuffer = {}
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ringbuffer.__index = ringbuffer
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local function new(...)
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local rb = {}
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rb.items = {...}
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rb.current = 1
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return setmetatable(rb, ringbuffer)
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end
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function ringbuffer:insert(item, ...)
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if not item then return end
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-- insert rest before self so order is restored, e.g.:
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-- {1,<2>,3}:insert(4,5) -> {1,<2>,3}:insert(5) -> {1,<2>,5,3} -> {1,<2>,4,5,3}
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self:insert(...)
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table.insert(self.items, self.current+1, item)
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end
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function ringbuffer:append(item, ...)
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if not item then return end
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self.items[#self.items+1] = item
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return self:append(...)
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end
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function ringbuffer:removeAt(k)
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-- wrap position
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local pos = (self.current + k) % #self.items
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while pos < 1 do pos = pos + #self.items end
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-- remove item
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local item = table.remove(self.items, pos)
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-- possibly adjust current pointer
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if pos < self.current then self.current = self.current - 1 end
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if self.current > #self.items then self.current = 1 end
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-- return item
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return item
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end
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function ringbuffer:remove()
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return table.remove(self.items, self.current)
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end
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function ringbuffer:get()
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return self.items[self.current]
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end
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function ringbuffer:size()
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return #self.items
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end
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function ringbuffer:next()
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self.current = (self.current % #self.items) + 1
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return self:get()
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end
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function ringbuffer:prev()
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self.current = self.current - 1
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if self.current < 1 then
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self.current = #self.items
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end
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return self:get()
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end
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-- the module
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return setmetatable({new = new},
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{__call = function(_, ...) return new(...) end})
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