Helper module which allows the rotation of square and non square arrays.

--================================================================================== -- Copyright (C) 2017 by Robert Machmer = -- = -- Permission is hereby granted, free of charge, to any person obtaining a copy = -- of this software and associated documentation files (the "Software"), to deal = -- in the Software without restriction, including without limitation the rights = -- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell = -- copies of the Software, and to permit persons to whom the Software is = -- furnished to do so, subject to the following conditions: = -- = -- The above copyright notice and this permission notice shall be included in = -- all copies or substantial portions of the Software. = -- = -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR = -- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, = -- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE = -- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER = -- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, = -- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN = -- THE SOFTWARE. = --==================================================================================

local ArrayRotation= { _VERSION = "1.0.0", _DESCRIPTION = "Rotation of arrays in 90° increments." , _URL = 'https://gist.github.com/rm-code/4118d4a97d8cde16952199d94b84ead0', }

---

-- Private Functions

---

---

-- Rotates a two dimensional array by 90°. -- @tparam table arr The array to rotate. -- @treturn table The rotated array.

local function rotate90( arr ) local rotatedArray = {} for x = 1, #arr do for y = 1, #arr[x] do local r, c = #arr-(x-1), y rotatedArray[c] = rotatedArray[c] or {} rotatedArray[c][r] = arr[x][y] end end return rotatedArray end

---

-- Rotates a two dimensional array by 180°. -- @tparam table arr The array to rotate. -- @treturn table The rotated array.

local function rotate180( arr ) local rotatedArray = {} for x = 1, #arr do for y = 1, #arr[x] do local r, c = #arr-(x-1), #arr[x]-(y-1) rotatedArray[r] = rotatedArray[r] or {} rotatedArray[r][c] = arr[x][y] end end return rotatedArray end

---

-- Rotates a two dimensional array by 270°. -- @tparam table arr The array to rotate. -- @treturn table The rotated array.

local function rotate270( arr ) local rotatedArray = {} for x = 1, #arr do for y = 1, #arr[x] do local r, c = x, #arr[x]-(y-1) rotatedArray[c] = rotatedArray[c] or {} rotatedArray[c][r] = arr[x][y] end end return rotatedArray end

---

-- Public Functions

---

---

-- Rotates a two dimensional array. -- @tparam table arr The array to rotate. -- @tparam number steps The amount of rotation to apply (0=0°, 1=90°, 2=180°, 3=270°) -- @treturn table The rotated array.

function ArrayRotation.rotate( arr, steps ) if steps == 0 then return arr elseif steps == 1 then return rotate90( arr ) elseif steps == 2 then return rotate180( arr ) elseif steps == 3 then return rotate270( arr ) end end

return ArrayRotation