Software / code / prosody
Changeset
5857:8613888d0f9e
util.array: Improve array:reverse() and make it work as both method and non-mutating function
| author | Kim Alvefur <zash@zash.se> |
|---|---|
| date | Sun, 06 Oct 2013 23:18:54 +0200 |
| parents | 5856:e3e593eb81d1 |
| children | 5858:89b16a160cbc 5859:e327f2d4e09f |
| files | util/array.lua |
| diffstat | 1 files changed, 20 insertions(+), 9 deletions(-) [+] |
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line diff
--- a/util/array.lua Sun Oct 06 23:17:05 2013 +0200 +++ b/util/array.lua Sun Oct 06 23:18:54 2013 +0200 @@ -11,6 +11,7 @@ local setmetatable = setmetatable; local math_random = math.random; +local math_floor = math.floor; local pairs, ipairs = pairs, ipairs; local tostring = tostring; @@ -84,6 +85,25 @@ return outa; end +function array_base.reverse(outa, ina) + local len = #ina; + if ina == outa then + local middle = math_floor(len/2); + len = len + 1; + local o; -- opposite + for i = 1, middle do + o = len - i; + outa[i], outa[o] = outa[o], outa[i]; + end + else + local off = len + 1; + for i = 1, len do + outa[i] = ina[off - i]; + end + end + return outa; +end + --- These methods only mutate the array function array_methods:shuffle(outa, ina) local len = #self; @@ -94,15 +114,6 @@ return self; end -function array_methods:reverse() - local len = #self-1; - for i=len,1,-1 do - self:push(self[i]); - self:pop(i); - end - return self; -end - function array_methods:append(array) local len,len2 = #self, #array; for i=1,len2 do
